Rush-Larsen time-stepping methods of high order for stiff problems in cardiac electrophysiology

To address the issues of stability and accuracy for reaction-diffusion equations, the development of high order and stable time-stepping methods is necessary. This is particularly true in the context of cardiac electrophysiology, where reaction-diffusion equations are coupled with stiff ODE systems. Many research have been led in that way in the past 15 years concerning implicit-explicit methods and exponential integrators. In 2009, Perego and Veneziani proposed an innovative time-stepping method of order 2. In this paper we present the extension of this method to the orders 3 and 4 and introduce the Rush-Larsen schemes of order k (shortly denoted RL\_k). The RL\_k schemes are explicit multistep exponential integrators. They display a simple general formulation and an easy implementation. The RL\_k schemes are shown to be stable under perturbation and convergent of order k. Their Dahlquist stability analysis is performed. They have a very large stability domain provided that the stabilizer associated with the method captures well enough the stiff modes of the problem. The RL\_k method is numerically studied as applied to the membrane equation in cardiac electrophysiology. The RL k schemes are shown to be stable under perturbation and convergent oforder k. Their Dahlquist stability analysis is performed. They have a very large stability domain provided that the stabilizer associated with the method captures well enough the stiff modes of the problem. The RL k method is numerically studied as applied to the membrane equation in cardiac electrophysiology

Potentialities for payment mechanisms for environmental services in the Congo Basin forests : The case of biodiversity conservation

The present study investigates the potential for direct payment for biodiversity conservation implementation in the Congo Basin. A survey realized in 31 protected areas in the Congo Basin showed that some initiatives, starting with raising awareness, are used to raise local participation in conservation, but there are very few conservation agreements with local people. Attempt to biodiversity conservation in/around PAs is done through three main approaches. Indirect incentive approaches are the most used (63%) in front of direct incentives for sustainable biodiversity use (30%). Direct incentives for biodiversity conservation (7%) are quite new and are still not bound by conservation contracts. Five initiatives are being implemented including rewards for denunciating poachers (in 2 PAs), conservation of marine turtles in Campo Ma¿an TUO, compensation of farmers for damages caused by wildlife in their farmland and paying a local community to set aside an area as no man¿s land for carbon sequestration evaluation. Three other initiatives are still in their planning phase. They are conservation concession projects proposed by conservation organizations (WWF, CI and BCI) to governments of Cameroon, CAR and DRC. Use-restriction on some elements of the biodiversity like wildlife is likely to be the best PES scheme in the Congo Basin compared to area-based schemes, since people heavily depend on land for their livelihood. The success of the conservation contracts will depend on securing property rights, a careful evaluation of opportunity costs considering ways and customs of local people, a clear definition of indicators (people efforts and results), a democratic and equitable use of compensation funds and an establishment of a strong institutional framework and monitoring authority for contract enforcement. All this may involve high transaction costs to improve efficiency of payments. Conservation contracts in the Congo Basin may not be such a cheap way to achieve biodiversity conservation as thought by many conservationists. A part from biodiversity market, possible mechanisms to finance them can be Trust fund for PA management and the future REDD mechanism. Finally, government efforts in clarification of customary rights will be required. However, the efficiency of conservation contracts to achieve biodiversity conservation is widely recognized and there is a great interest of conservationists for direct payments for biodiversity conservation in the Congo Basin. (Résumé d'auteur

A computer code for forward calculation and inversion of the H/V spectral ratio under the diffuse field assumption

During a quarter of a century, the main characteristics of the horizontal-to-vertical spectral ratio of ambient noise HVSRN have been extensively used for site effect assessment. In spite of the uncertainties about the optimum theoretical model to describe these observations, several schemes for inversion of the full HVSRN curve for near surface surveying have been developed over the last decade. In this work, a computer code for forward calculation of H/V spectra based on the diffuse field assumption (DFA) is presented and tested.It takes advantage of the recently stated connection between the HVSRN and the elastodynamic Green's function which arises from the ambient noise interferometry theory. The algorithm allows for (1) a natural calculation of the Green's functions imaginary parts by using suitable contour integrals in the complex wavenumber plane, and (2) separate calculation of the contributions of Rayleigh, Love, P-SV and SH waves as well. The stability of the algorithm at high frequencies is preserved by means of an adaptation of the Wang's orthonormalization method to the calculation of dispersion curves, surface-waves medium responses and contributions of body waves. This code has been combined with a variety of inversion methods to make up a powerful tool for passive seismic surveying.Comment: Published in Computers & Geosciences 97, 67-7

Contribution to the Taking into Account of Environmental Factors of Vulnerability of Reinforced Concrete Buildings in the City of Douala-Cameroon

The environment of the city of Douala (humid, porous, sandy-clay soil), plays a determining role on the vulnerability of reinforced concrete constructions, by effects of corrosion of degradations, and destructions of the structures (buildings). Relative Y, the method tree of the causes and the tests pH-metric, granulometric and permeameters , allowed us to seek, to check and to analyze certain environmental factors impacting on the constructions, weakening the concrete and pari cochet , the resistance and the durability of the buildings. To this end, the pH tests of groundwater, springs and industrial discharges, containing chloride ions (Cl-), sulphates and carbon dioxides from heavy rainfall and flooding, attack by an electrochemical mechanism the reinforcement and framework of the constructions. Thus, the results obtained from the tests, demonstrate how the dangerous acids present in water, penetrate into the reinforced concrete to destroy it. The resulting chemical reaction of hydration absorbs the water and swells the concrete to reach the steel, weakening it and destroying the protective film (passivation). The action of water on concrete is declined by absorption, hydrolysis, dissolution, solvation and crystallization. Also, the corrosion rate of materials remaining strongly inherent to the high humidity and PH level ? 6, directly influencing the electrical resistivity conductivity and diffusion of oxygen and carbon dioxide in concrete. As such, the relative humidity (RH) or high water content in concrete and the environment of the site receiving the construction project, produces permeability decreasing effects in the presence of oxygen. These effects contribute to stimulate and increase the corrosion process. Because, water, soil and industrial pollutants, affect the works Given, that it is demonstrated that a quasi-permanent moisture content ? 55% in a porous material such as concrete, leads to the loss of 20 to 30% of its cohesion. Hence, the various forms of degradation and loss of loads suffered by the constructions. To this end, the binder content, mineral additives and the water/cement ratio (W/C), are to be considered for the evaluation, resistance and durability of the constructions. Also, most of the methods used to determine the permeability of porous materials are based on Darcy's law. This is because, in its basic form, the fluid flows through a disc-shaped sample under a pressure gradient. Consequently, in addition to the requirement of carrying out geotechnical studies of materials and soil in accordance with the standards of construction and urban planning, pH metric tests are necessary for the effective consideration of environmental factors to achieve the resilience and durability of reinforced concrete structures. It will be in particular: ( i ) to identify and analyze the impacts of water and soil on reinforced concrete constructions; (ii) to verify and analyze the compliance of the said constructions with the geotechnical and urban planning standards (realization of geotechnical studies and the use of adequate quality materials and qualified manpower); (iii) to contribute to the considerable reduction of the vulnerability of the works to the attacks of the sulphates , for a better safety and durability of the constructions

Design and implementation of an experimental thermoelectric system from wood waste

This study was carried out at Dino & Fils SA, a wood processing unit in Soa-Cameroon. The aim was to recover energy from wood waste in order to contribute to greater energy flexibility in wood processing units. Specifically, the aim was to assess the quantity of wood waste available on the site and estimate its energy potential, to design and test a system for producing electrical energy from this waste, and to estimate the contribution of this thermoelectric system to meeting the company's energy needs and the associated costs. Wood waste was characterized by taking measurements at each station on the production line, supplemented by monthly production reports and scientific data. For the month of March 2024, the plant produced 3 284 m³ of wood waste or 64% of the gross wood volume. This is equivalent to 2 766 tons for an electrical energy potential of 571 MWh; the company's monthly electricity consumption is estimated at 121 MWh. The experimental thermoelectric system set up, using the TEC1-12715 Peltier module, produced electricity with a total power of 841 W and a Seebeck coefficient of 0.04 V°C⁻¹ by burning 5 kg of sawdust for 85 minutes. On a real scale and under optimum conditions, this system would be an effective and viable solution for covering not only all the energy needs of Dino & Fils SA but also those of surrounding households and offices at a competitive cost of 48 FCFA/kWh

Design and implementation of an experimental thermoelectric system from wood waste

This study was carried out at Dino & Fils SA, a wood processing unit in Soa-Cameroon. The aim was to recover energy from wood waste in order to contribute to greater energy flexibility in wood processing units. Specifically, the aim was to assess the quantity of wood waste available on the site and estimate its energy potential, to design and test a system for producing electrical energy from this waste, and to estimate the contribution of this thermoelectric system to meeting the company's energy needs and the associated costs. Wood waste was characterized by taking measurements at each station on the production line, supplemented by monthly production reports and scientific data. For the month of March 2024, the plant produced 3 284 m³ of wood waste or 64% of the gross wood volume. This is equivalent to 2 766 tons for an electrical energy potential of 571 MWh; the company's monthly electricity consumption is estimated at 121 MWh. The experimental thermoelectric system set up, using the TEC1-12715 Peltier module, produced electricity with a total power of 841 W and a Seebeck coefficient of 0.04 V°C⁻¹ by burning 5 kg of sawdust for 85 minutes. On a real scale and under optimum conditions, this system would be an effective and viable solution for covering not only all the energy needs of Dino & Fils SA but also those of surrounding households and offices at a competitive cost of 48 FCFA/kWh

Design and Implementation of an Experimental Thermoelectric System From Wood Waste

This study was carried out at Dino & Fils SA, a wood processing unit in Soa-Cameroon. The aim was to recover energy from wood waste in order to contribute to greater energy flexibility in wood processing units. Specifically, the aim was to assess the quantity of wood waste available on the site and estimate its energy potential, to design and test a system for producing electrical energy from these waste and to estimate the contribution of this thermoelectric system to meeting the company's energy needs and the associated costs. Wood waste were characterized by taking measurements at each station on the production line, supplemented by monthly production reports and scientific data. For the month of March 2024, the plant produced 3 284 m³ of wood waste, or 64% of the gross wood volume. This is equivalent to 2 766 tons for an electrical energy potential of 571 MWh; the company's monthly electricity consumption is estimated at 121 MWh. The experimental thermoelectric system set up, using the TEC1-12715 Peltier module, produced electricity with a total power of 841 W and a Seebeck coefficient of 0.04 V°C⁻¹ by burning 5 kg of sawdust for 85 minutes. On a real scale and under optimum conditions, this system would be an effective and viable solution for covering not only all the energy needs of Dino & Fils SA but also those of surrounding households and offices at a competitive cost of 48 FCFA/kWh

Dynamics of charge movement in ∞-Al2O3:C,Mg using thermoluminescence phototransferred and optically stimulated luminescence

vital:57237The dosimetric features of ∞-Al2O3:C,Mg have been investigated for unannealed and annealed samples. The unannealed sample is referred to as sample A whereas the samples annealed at 700, 900 and 1200°C for 15 minutes each are referred to as samples B, C and D respectively. A glow curve of unannealed ∞-Al2O3:C,Mg measured at 1°C/s after irradiation to 2.0 Gy consists of peaks at 43, 73, 164, 195, 246, 284, 336 and 374°C respectively. For sample B (annealed at 700°C), a glow curve measured at 1°C/s after irradiation to 3.0 Gy has peaks at 46, 76, 100, 170, 199, 290, 330 and 375°C whereas the glow curve of sample C (annealed at 900°C) recorded under the same conditions consists of peaks at 49, 80, 100, 174, 206, 235, 290, 335 and 375°C respectively. Sample D (annealed at 1200°C) is the most sensitive of the four samples. A glow curve of sample D measured at 1°C/s after irradiation to 0.2 Gy has peaks at 52, 82, 102, 174, 234, 288 and 384°C respectively. The peaks are labelled I-VIII in order of appearance. The 100°C peak, labelled IIa, is induced by annealing at or above 700°C. The dose response of these peaks was studied for doses within 0.1-8.2 Gy. The reported peaks follow first-order kinetics irrespective of annealing temperature. Peaks I-III of each sample are reproduced under phototransfer for preheating up to 400°C. For the unannealed sample, the reproduced peaks are labelled A1-A3 whereas for the annealed samples, they are labelled B1-B3, C1-C3 and D1-D3 respectively. The annealing-induced peak at 100°C is reproduced as B2a, C2a and D2a for samples B, C and D respectively. A PTTL peak labelled C2b or D2b is also observed near 140°C in samples C and D. In addition to these PTTL peaks, a PTTL peak corresponding to peak IV is also found for sample D and for the unannealed sample. As the corresponding conventional peaks, the PTTL peaks of each sample follow first-order kinetics. Peak I and its corresponding PTTL peak for each sample are unstable and fade to a minimal level after 300 s of storage time. On the other hand, peak II of each sample and its corresponding PTTL peak could still be observed with delay up to 5000 s. Peak III of the unannealed sample remains stable with storage time up to 48 hours. Irrespective of annealing, the trap corresponding to peak III is the most sensitive to optical stimulation. Time-dependent profiles of PTTL from unannealed and annealed ∞-Al2O3:C,Mg were also studied. The mathematical analysis of the PTTL time-response profiles is based on experimental results. The role of various electron traps in PTTL was determined by using pulse annealing and by monitoring the dependence of peak intensity on duration of illumination for peaks not removed by preheating. The presence and role of deep traps were further demonstrated with thermally assisted optically stimulated luminescence. For the unannealed sample, the activation energy for thermal assistance is 0.033 ± 0.001 eV and the activation energy for thermal i quenching is 1.043 ± 0.001 eV. For sample C, the activation energy for thermal assistance is 0.044 ± 0.003 eV whereas that for thermal quenching is 1.110 ± 0.006 eV. The values for the activation energy for thermal assistance are lower than those reported in literature. Only the values for the activation energy for thermal quenching are somewhat comparable to values reported elsewhere.Thesis (PhD) -- Faculty of Science, Physics and Electronics, 202

L'effet des caractéristiques du territoire et du paysage sur les décisions d'achat du prosecco : une expérience de choix

The Ministerial Decree of 17 July 2009 amended the specification of the production of Prosecco. Between the main innovations of the decree, there is the introduction of the Denomination of Controlled and Guaranteed Origin (DOCG) for the historic production area of Prosecco, which is located between the towns of Conegliano and Valdobbiadene. The extension of the DOC area production is the second one, and now encompass the provinces of Belluno, Padua, Treviso, Venice and Vicenza in the Veneto and those Gorizia, Pordenone, Trieste and Udine in the region of Friuli Venezia Giulia. The new disciplinary was created in order to protect the production of Prosecco against counterfeits which are becoming more common on the market. The goal of our research is to develop a study to determine if and how extent the characteristics of the territory and the landscape can become tools for the valuation of the typicality of wine production, with particular reference to the production of Prosecco. The recent expansion of the area production of Prosecco DOC has set new challenges for wine producers that operate in the area that was previously the DOC of Conegliano Valdobbiadene Prosecco, became a DOCG area. The idea we have is to check if the market is able to recognize the characteristics of the wines produced in the DOCG and if they will keep the golden place they had already acquired on the market. In this regard, we have identified some typical elements of DOCG, and we tried to see using Discrete Choice Experiment whether they can be used as marketing tools or in other words, if these characteristics can allow companies of the hilly area oh this region to acquire the market power. In this context, a special questionnaire was built to conduct interviews, and these allowed us to collect informations related to the consumption of wine in general and those of Prosecco in particular. Socio-economics informations where also collected in order to better characterise the sample of respondents. Using a sample of 556 interviews, research allowed us to understand how some intrinsic attributes (using of local grapes biotypes) and extrinsic (landscape protection, traceability, belonging to the DOCG production area), are be able to influence the purchase consumers behaviour. In particular, producers of the hilly area should use grapes from local biotypes, ensure accurate traceability, and promote the conservation of traditional vineyard landscapes in order to increase the propensity to buy Prosecco DOCG wines. In addition, it is necessary that the Consortium for the Protection of Prosecco DOCG should implement targeted marketing strategies to promote the meaning of Acronym DOCG, and those that will try to highlight the differences between the Prosecco DOC and DOCG