Synthesis and Characterization of Local Bio-Sourced Geopolymer Binder: Application to Compressed Earth Blocs

The construction industry continues to rely on conventional materials like cement,which often can come with a high cost and significant environmental impact,particularly in terms of greenhouse gas emissions.To tackle the challenges of sustainable development,there is growing interest in using local available materials with low environmental impact.This study primarily focuses on synthesizing and characterizing a geopolymer binder made from local materials found in Benin to stabilize CEB(compressed earth brick).The synthesis involves combining amorphous aluminosilicate powder with a highly concentrated alkaline solution.Local calcined kaolinite clay(metakaolin)and corn cob ash obtained after calcination at 600°C were used with a 12 M sodium hydroxide(NaOH)solution.Different mixtures of geopolymer were formulated substituting metakaolin by corn cob ash at rates of 0%,5%,10%,and 15%of the dry weight of the mixture.Thereafter physical and mechanical characterization tests were conducted on each formulation.Results showed that geopolymer binders containing 85%metakaolin and 15%corn cob ash exhibited the best physical and mechanical performance(e.g.12.08 MPa for compression strength).Subsequently,this geopolymer formulation was used to stabilize CEB.Characterization revealed that CEBs stabilized with 10%geopolymer exhibit good mechanical properties(6.93 MPa),comparable to those of CEBs stabilized with 10%cement(7.40 MPa),justifying their use as load-bearing walls in construction.

Effect of Supplementary Irrigation on the Yield of Sorghum (Sorghum bicolor L. Moench) in the Context of Climate Change in the Dry Savannahs of Togo

Under the current context of climate change, supplementary irrigation may be needed for crop production resilience. We determined the effects of supplementary irrigation on sorghum grain yield in the dry Savannah region of Togo. A two-year trial was conducted in a controlled environment at AREJ, an agro-ecological center in Cinkassé. The plant material was sorghum variety Sorvato 28. The experimental design was a Completely Randomized Block with three replications and three treatments as follows: T0 control plot (rainfed conditions);T1 (supplementary irrigation from flowering to grain filling stage) and T2 (supplementary irrigation from planting to grain filling stage). Two irrigation techniques (furrow and Californian system) were used under each watering treatment. The results showed that irrigation technique significantly affected panicle length with no effect on 1000 grains mass. Panicle length and grain yields varied from 15.59 to 25.71 cm and 0.0 to 2.06 t∙h−1, respectively, with the highest values (25.66 cm and 2.06 t∙h−1, respectively) under the T2 treatment with the California system-based supplementary irrigation. The comparison of results obtained on treatment T0 and T2, shows that supplementary irrigation increased the yields by at least 68.62%. Supplementary irrigation during sowing and growing season (T2) improved sorghum yields in the dry savannahs of Togo, with a better performance of the California irrigation system.

Development and Characterization of Particle Boards Based on Sorghum Husk

This study tackles current environmental challenges by developing innovative and eco-friendly particle boards utilizing sorghum husk, combined with recycled expanded polystyrene (EPS). This dual eco-responsible approach valorizes sorghum husk, often deemed agricultural waste, and repurposes EPS, a plastic waste, thus contributing to CO2 emission reduction and effective waste management. The manufacturing process involves dissolving recycled polystyrene within a solvent to create a binder, which is then mixed with sorghum husk and cold-pressed into composite boards. The study explores the impact of two particle sizes (fine and coarse) and two different concentrations of the recycled EPS binder. Results demonstrate significant variations in the boards’ mechanical properties, displaying a range of Modulus of Rupture (MOR) from 0.84 MPa to 3.85 MPa, and Modulus of Elasticity (MOE) spanning from 658.13 MPa to 1313.25 MPa, influenced by the binder concentration and particle size. These characteristics suggest that the boards can be effectively used in various construction applications, including interior decoration, false ceilings, and potentially for furniture and door manufacturing when combined with appropriate coatings. This study not only exemplifies the valorization of plastic and agricultural wastes but also offers a practical, localized solution to global climate change challenges by promoting sustainable construction materials.

Performance Evaluation of Novel Eco-Materials Composed of Millet Husks, Rice Husks, and Polystyrene

Managing agricultural waste and expanded polystyrene (EPS) poses significant environmental and economic challenges. This study aims to create composites from millet husks, rice husks, and recycled EPS, using a manufacturing method that involves dissolving the polystyrene in a solvent followed by cold pressing. Various particle sizes and two binder dosages were investigated to assess their influence on the physico-mechanical properties of the composites. The mechanical properties obtained range from 2.54 to 4.47 MPa for the Modulus of Rupture (MOR) and from 686 to 1400 MPa for the Modulus of Elasticity in Bending (MOE). The results indicate that these composites have potential for applications in the construction sector, particularly for wood structures and interior decoration. Moreover, surface treatments could enhance their durability and mechanical properties. This research contributes to the valorization of agricultural and plastic waste as eco-friendly and economical construction materials.

Effects of Prandtl and Jacob Numbers and Dimensionless Thermal Conductivity on Velocity Profiles in Media (Porous and Liquid)

In this present study, we analyzed the effects of Prandtl and Jacob numbers and dimensionless thermal conductivity on the velocity profiles in media (porous and liquid). The transfers in the porous medium and the liquid film are described respectively by the improved Wooding model and the classical boundary layer equations. The mesh of the digital domain is considered uniform in the transverse and longitudinal directions. The advection and diffusion terms are discretized with a back-centered and centered scheme respectively. The coupled systems of algebraic equations thus obtained are solved numerically using an iterative line-by-line relaxation method of the Gauss-Seidel type. The results show that the parameters relating to the thermal problem (the dimensionless thermal conductivity, the Prandtl (Pr) and Jacob (Ja) numbers) have no influence on the dimensionless speed, although the thermal and hydrodynamic problems are coupled. Via the heat balance equation. The results obtained show that the parameters relating to the thermal problem have no influence on the dimensionless speed, although the thermal and hydrodynamic problems are coupled via the heat balance equation. So, at first approximation with the chosen constants, we can solve the hydrodynamic problem independently of the thermal problem.

Study of Rice Husks and Expanded Polystyrene Composites for Construction Applications

In the current context of environmental challenges, this study focuses on developing innovative and eco-friendly composites using rice husk and recycled expanded polystyrene. This dual-responsibility approach valorizes a by-product like rice husk, often considered waste, and reuses polystyrene, a plastic waste, thereby contributing to CO2 emission reduction and effective waste management. The manufacturing process involves dissolving recycled polystyrene into a solvent to create a binder, which is then mixed with rice husk and cold-compacted into composite materials. The study examines the impact of two particle sizes (fine and coarse) and different proportions of recycled polystyrene binder. The results show significant variations in the mechanical characteristics of the composites, with Modulus of Rupture (MOR) values varying from 2.41 to 3.47 MPa, Modulus of Elasticity (MOE) ranging from 223.41 to 1497.2 MPa, and Stiffness Coefficient (K) from 5.04 to 33.96 N/mm. These characteristics demonstrate that these composites are appropriate for various construction applications, including interior decoration, panel claddings, and potentially for furniture and door manufacturing when combined with appropriate coatings. This study not only highlights the recycling of agricultural and plastic waste but also provides a localized approach to addressing global climate change challenges through the adoption of sustainable building materials.

Acetic acid-and furfural-based adaptive evolution of Saccharomyces cerevisiae strains for improving stress tolerance and lignocellulosic ethanol production

Acetic acid and furfural are known as prevalent inhibitors deriving from pretreatment during lignocellulosic ethanol production.They negatively impact cell growth,glucose uptake and ethanol biosynthesis of Saccharomyces cerevisiae strains.Development of industrial S.cerevisiae strains with high tolerance towards these inhibitors is thus critical for efficient lignocellulosic ethanol production.In this study,the acetic acid or furfural tolerance of different S.cerevisiae strains could be significantly enhanced after adaptive evolution via serial cultivation for 40 generations under stress conditions.The acetic acid-based adaptive strain SPSC01-TA9 produced 30.5 g·L^(-1)ethanol with a yield of 0.46 g·g^(-1)in the presence of 9 g·L^(-1)acetic acid,while the acetic acid/furfural-based adaptive strain SPSC01-TAF94 produced more ethanol of 36.2 g·L^(-1)with increased yield up to 0.49 g·g^(-1)in the presence of both 9 g·L^(-1)acetic acid and 4 g·L^(-1)furfural.Significant improvements were also observed during non-detoxified corn stover hydrolysate culture by SPSC01-TAF94,which achieved ethanol production and yield of 29.1 g·L^(-1)and 0.49 g·g^(-1),respectively,the growth and fermentation efficiency of acetic acid/furfural-based adaptive strain in hydrolysate was 95%higher than those of wildtype strains,indicating the acetic acid-and furfural-based adaptive evolution strategy could be an effective approach for improving lignocellulosic ethanol production.The adapted strains developed in this study with enhanced tolerance against acetic acid and furfural could be potentially contribute to economically feasible and sustainable lignocellulosic biorefinery.

Hydrochemistry of Groundwater in the Rice Cultivation Area of Maga: Analysis of the Mineralization Process

The use of groundwater for drinking water supply to the population is increasingly practiced in the rice cultivation area of Maga. However, there is a lack of knowledge about the hydrochemical characteristics of this water due to a lack of quality control. This study aims to contribute to the understanding of mineralization processes in order to establish the hydrochemical profile of the water in the area. The methodological approach consisted of collecting fifteen water samples from wells and boreholes during six campaigns for physicochemical analysis, and studying them through methods of interpreting hydrochemical data. The analysis results show that these waters are moderately mineralized. The water facies are mainly of the bicarbonate sodium and potassium type, as well as the bicarbonate calcium and magnesium type. Calculation of saturation indices demonstrates that evaporite minerals show lower degrees of saturation than carbonate minerals, with gypsum, anhydrite, and halite being in a highly undersaturated state. The mineralization of groundwater originates from the dissolution of surrounding rocks on the one hand, and anthropogenic activities involving exchanges between alkalis (Na+ and K+) in the aquifer and alkaline earth (Ca2+ and Mg2+), resulting in the fixation of alkaline earth and the dissolution of alkalis.

Decline and dieback of cork oak(Quercus suber L.)forests in the Mediterranean basin:a case study of Kroumirie,Northwest Tunisia

Assessing the vulnerability of forest ecosystems in the climate change context is a challenging task as the mechanisms that determine this vulnerability cannot be directly observed.Based on the ecological interrelationships between forests and climate,the present review focused on providing current information about vulnerability assessments of cork oak(Quercus suber L.)forests in the Mediterranean basin,especially,in the Kroumirie region(northwest Tunisia),currently under historic extreme drought conditions.From comparing recent findings in this region,we synthesized data on cork oak decline and mortality collected during the historic drought years 1988–1995 period.Climate change impacts cork forest decline,with special interest shown in elevated temperatures and drought;cork oak forest regeneration,and the adaptation of the Kroumirie forest to climate change,are reviewed herein.The studied region has been influenced largely by frequent prolonged drought periods,especially from 1988 to 1995.Droughts were found to consistently have a more detrimental impact on the growth and mortality rates of cork oak populations.Cork oak mortality was recorded for up to 63,622 trees.In the future,more research studies and observational data will be needed,which could represent an important key to understand ecosystem processes,and to facilitate the development of better models that project climate change impacts and vulnerability.The study is useful for researchers and forestry decision makers to develop the appropriate strategies to restore and protect ecosystems,and to help anticipate potential future droughts and climate change.

Fluoride in Tunisian Drinking Tap Water

This paper presents a fluoride health risk characterization approach to identify the hyper-sensitive population of adverse effect like tooth decay, dental fluorosis and skeletal fluorosis. In this context, a sampling campaign has been done over 100 Tunisian water consumption points (tap). Laboratory analysis results show that the quality of drinking water is affected by high fluoride concentration level exceeding 2 mg·L-1. Over these samples, 7% of them present non-compliant with the Tunisian national standard (NT09.14) and the international guidelines (World Health Organization recommendations, WHO). The overtake cases are located essentially in southern Tunisian areas, i.e. Medenine, Gabes, Gafsa and Tataouine. One can highlight that groundwater, in these southern Tunisian areas, are naturally rich of fluoride. This is because of the aquifers geological and fossil nature. However, commonly northern and central Tunisian areas are characterized by low fluoride concentration level below 0.1 mg·L-1. These undertaken cases don’t meet the water quality requirement defined by WHO.

Development of a Data Acquisition System to Optimizing the Agricultural Tractor Performance

A novel data acquisition system was successfully integrated on-board the Massey Ferguson 3,000 series agricultural tractors for measuring tractor-implement performance. A commercial load cell was incorporated into the existing system for the needed tractor-implement performance, measurements. This system is capable of measuring, displaying and recording, in real-time, the tractor＇s theoretical travel speed, the actual travel speed, the engine speed, the fuel consumption rate, and the drawbar pull. Static calibration tests on various associated sensors for the required measurements show excellent linearity with correlation coefficients that are close to 1. The developed system was extensively and successfully field demonstrated for tractor-implement performance with offset disc harrows on dry, undisturbed loamy soils. Under these conditions, a ratio of tractor power to implement width is suggested. The data also show the existence of a linear relationship between fuel consumption per hectare and specific draught, for the 4 to 9 kN m^-1 range, which suggests the possibility of extending the American Society of Agricultural and Biological Engineers model of draught prediction to forecast fuel consumption. The configuration of the tractor-harrow combination, based on the measurement of the draught required under operational conditions, provides the manufacturers with a reliable indication of the recommended power required for each harrow model. With this type of information farmers can make decisions regarding selection of a suitable tractor-implement combination for their farms. As a consequence, there is improved tractor-harrow productivity and field efficiency.

Enhancement of Au–Ag–Te contents in tellurium-bearing ore minerals via bioleaching

The purpose of this study was to enhance the content of valuable metals, such as Au, Ag, and Te, in tellurium-bearing minerals via bioleaching. The ore samples composed of invisible Au and Au paragenesis minerals(such as pyrite, chalcopyrite, sphalerite and galena) in combination with tellurium-bearing minerals(hessite, sylvanite and Tellurobismuthite) were studied. Indigenous microbes from mine drainage were isolated and identified as Acidithiobacillus ferrooxidans, which were used in bioleaching after adaption to copper. The effect of the microbial adaption on the bioleaching performance was then compared with the results produced by the non-adaptive process. The microbial adaption enhanced the Au–Ag–Te contents in biological leaching of tellurium-bearing ore minerals. This suggests that bioleaching with adapted microbes can be used both as a pretreatment and in the main recovery processes of valuable metals.

Salinity Risk and Management in Tunisian Semi Arid Area

In semi arid and arid countries, the increase in production needs sometimes using brackish/saline water for irrigation. In Kairouan and Mahdia （Centre of Tunisia）, most of the irrigated areas are by pumping ground water from wells and in many cases, water has more than 4 g of salt per liter. To improve farmers＇ income through using efficiently brackish/saline and rare water, applied research programme was carried out. The methodology adopted was based on selection of six farmers＇ parcels. Behind water quality and quantity, soil salinity and crop response, the crop cost was studied： initial and final characterization and frequently controlled. Three different water regimes were observed induced three salinity regimes： an exclusively irrigated regime in summer based on using saline water producing continuous accumulation of salts, an irrigated-rained regime in autumn/spring based on alternated saline and fresh water inducing cyclic accumulation and leaching of salts and a rained regime in winter based on fresh water with continuous leaching of salts. At the short term, soil salinity increased under irrigation until equilibrium with the irrigation water quality and decreased by rain which produced an important salts leaching in a very short time. Many tons of salts were added to the initial stock in summer season and most of them are leached to the subsoil under irrigation and by rain in the winter. Salinization affected the deep layer and on the long term, salinization of the aquifer might occur. An important crop yield decrease for the summer crop was obtained but the socio-economic aspect appeared as an important factor conditioning the use of saline water.

Integrating multiple electromagnetic data to map spatiotemporal variability of soil salinity in Kairouan region, Central Tunisia

Soil salinization is a major problem affecting soils and threatening agricultural sustainability in arid and semi-arid regions,which makes it necessary to establish an efficient strategy to manage soil salinity and confront economic challenges that arise from it.Saline soil recovery involving drainage of shallow saline groundwater and the removal of soil salts by natural rainfall or by irrigation are good strategies for the reclamation of salty soil.To develop suitable management strategies for salty soil reclamation,it is essential to improve soil salinity assessment pro cess/mechanism and to adopt new approaches and techniques.T his study mapped a recovered area of 7200 m2 to assess and verify variations in soil salinity in space and time in K airouan region in Central Tunisia,taking into account the thickness of soil materials.Two electromagnetic conductivity meters(EM38 and EM31)were used to measure the electrical conductivity of saturated soil-paste extract(ECe)and apparent electrical conductivity(E Ca).Multiple linear regression was established between ECe and ECa,and it was revealed that ECa-EM38 is optimal for E Ce prediction in the surface soils.Salinity maps demonstrated that the spatial structure of soil salinity in the region of interest was relatively unchanged but varied temporally.Variation in salinity at the soil surface was greater than that at a depth.These findings can not only be used to track soil salinity variations and their significance in the field but also help to identify the spatial and temporal features of soil salinity,thus improving the efficiency of soil management.

High Lattice Match Growth of InAsSb Based Materials by Molecular Beam Epitaxy

High lattice match growth of InAsSb based materials on GaSb substrates is demonstrated. The present results indicate that a stable substrate temperature and the optimal flux ratios are of critical importance in achieving a homogeneous InAsSb based material composition throughout the growth period. The quality of these epilayers is assessed using a high-resolution x-ray diffraction and atomic force microscope. The mismatch between the GaSb substrate and InAsSb alloy achieves almost zero, and the rms surface roughness of InAsSb alloy achieves around 1.7A over an area of 28μm × 28μm. At the same time, the mismatches between GaSb and InAs/InAs0.73Sb0.27 superlattices （SLs） achieve approximately 100 arcsec （75 periods） and zero （300 periods）, with the surface rms roughnesses of InAs/InAs0.73Sb0.27 SLs around 1.8 A （75 periods） and 2.1A （300 periods） over an area of 20 μm×20 μm, respectively. After fabrication and characterization of the devices, the dynamic resistance of the n-barrier-n InAsSb photodetector near zero bias is of the order of 10^6Ω·cm^2. At 77K, the positive-intrinsic-negative photodetectors are demonstrated in InAsSb and InAs/InAsSb SL （75 periods） materials, exhibiting fifty-percent cutoff wavelengths of 3.8μm and 5.1μm, respectively.

Effects of Sky Conditions Measured by the Clearness Index on the Estimation of Solar Radiation Using a Digital Elevation Model

This study evaluated the effects of sky conditions (measured by the clearness index, KT) on the estimation of solar radiation and its components. Solar radiation was calculated by a digital elevation model derived from the Shuttle Radar Topography Mission (SRTM). The calculated radiation was parameterized and validated with measured solar radiation from two stations inside the urban perimeter of the city of Cuiabá, Brazil, during 2006 to 2008. The measured solar radiation varied seasonally, with the highest values in December-March and the lowest in June-September. Comparisons between calculated and measured values for two sites in Cuiabá demonstrate that the model is accurate for daily Rg estimates under clear sky conditions based on Root Mean Square Error, Mean Bias Error and Willmott’s index. However, under partially cloudy and cloudy sky conditions the model was not able to provide robust estimates. Spatially, the highest values of incident Rg occurred on strands with North, Northeast and Northwest orientations and were lowest on those oriented to the South, Southeast and Southwest.

Use of the SPAD-502 in Estimating Nitrogen Content in Leaves and Grape Yield in Grapevines in Soils with Different Texture

The SPAD reading may be used in estimating total nitrogen content (N) in leaves and even in estimating grape yield in grapevines. The objective of this study was to estimate total N content in leaves and grape yield using the SPAD-502 in grapevines submitted to nitrogen fertilization in soils with clayey and sandy texture. In 2008, two experiments were installed in the Southern region of Brazil. In experiment 1, Cabernet Sauvignon grapevines were planted in a soil with clayey texture and with application of 10, 20, 40 and 80 kg·N·ha-1·year-1. In experiment 2, Cabernet Sauvignon grapevines were planted in a soil with sandy texture and with the application of 0, 10, 15, 20, 40, 80 and 120 kg·N·ha-1·year-1. In the grapevines of the two experiments and during the period from 2008 to 2010, SPAD readings were made on leaves throughout the flowering period and at change in color of the berries using the portable chlorophyll meter Minolta-SPAD-502. The leaves were collected, dried, ground and submitted to analysis of the total N content. In addition, grape yield per hectare was evaluated. The SPAD-502 readings estimated the total N content in flowering and at change in color of the berries in the Cabernet Sauvignon grapevines grown on soils with clayey texture and sandy texture, especially in the first year of evaluation. However, the precision of the SPAD-502 readings is low, with there being no relationship between the SPAD-502 readings and grape yield.

大河系统洪水风险管理——德国的经验(论文摘编)(英文)

Problems with extreme floods have been aggravated in Germany mainly due to loss of flood retaining areas caused by river regulation measures in former centuries, and by intensified use of the former natural flood plains. The situation may have been worsened in the last decades by climate change.

Attenuation of coda waves in the SW of High-Atlas area, Morocco

We investigate attenuation scattering and loss properties in Souss basin(SW of High-Atlas) as a transition zone between the High and Anti Atlas ranges. This district consists in a thinned crustal patch with shallow seismicity and loose sedimentary trenches that perform an important contribution to augment seismic attenuation. So far, no coda waves approach in our knowledge have been used to draw satisfying outputs about the attenuation properties in the region. Therefore, this update suggests to correlate the lateral changes of seismic attenuation to different characteristics and asperities i.e. seismic activity,crustal age and thickness, heat flow, and ground deformation rate. To do so, we analysed coda waves derived from waveform data of more than 23 local earthquakes from seven broadband seismometers recorded during 2010 e2012 period. As a starter, we utilized the backscattering model which defines theseismic attenuation as inversely proportional to quality factor by the equation A ?1=. QQcestimates c were deducted at various central frequency bands 1.5, 3.0, 6.0, 9.0, 12.0 and 18.0 Hz according to different lapses times. The estimated average frequency dependence quality factor gives relation Qc? 120 f1;01,while the average Qcvalues vary from 149 at 1.5 Hz to 1895 at 18 Hz central frequencies. We observed an intimate dependence between quality factor and frequency ranges, which reflects the complexity of geological/geophysical pattern in the Souss basin and the presence of a variety of heterogeneities within the underlying crust.

Potential risk of soil irrigation with treated wastewater over 40 years:a field experiment under semi-arid conditions in northeastern Tunisia

In Tunisia,water scarcity is only adding pressure on water demand in agriculture.In the context of sustainable development goals,Tunisia has been reusing treated wastewater(TWW)as a renewable and inexpensive source for soil fertigation and groundwater(GW)recharge.However,major risks can be expected when the irrigation water is of poor quality.This study aims for evaluating the potential risk of TWW and GW irrigation on soil parameters.Accordingly,we evaluated the suitability of water quality through the analysis of major and minor cations and anions,metallic trace elements(MTEs),and the sodium hazard by using the sodium adsorption ratio(SAR)and the soluble sodium percentage(SSP).The risk of soil sodicity was further assessed by SAR and the exchangeable sodium percentage(ESP).The degree of soil pollution caused by MTEs accumulation was evaluated using geoaccumulation index(Igeo)and pollution load index(PLI).Soil maps were generated using inverse spline interpolation in ArcGIS software.The results show that both water samples(i.e.,TWW and GW)are suitable for soil irrigation in terms of salinity(electrical conductivity<7000μS/cm)and sodicity(SAR<10.00;SSP<60.00%).However,the contents of PO_(4)^(3-),Cu^(2+),and Cd^(2+)exceed the maximum threshold values set by the national and other standards.Concerning the soil samples,the average levels of SAR and ESP are within the standards(SAR<13.00;ESP<15.00%).On the other hand,PLI results reveal moderate pollution in the plot irrigated with TWW and no to moderate pollution in the plot irrigated with GW.Igeo results indicate that Cu^(2+)is the metallic trace element(MTE)with the highest risk of soil pollution in both plots(Igeo>5.00),followed by Ni^(2+)and Pb^(2+).Nevertheless,Cd^(2+)presents the lowest risk of soil pollution(Igeo<0.00).Statistical data indicates that Ca^(2+),Na+,Ni^(2+),and Pb^(2+)are highly distributed in both plots(coefficient of variation>50.0%).This study shows that the use of imagery tools,such as ArcGIS,can provide important information for evaluating the current status of soil fertility or pollution and for better managing soil irrigation with TWW.