Clay materials from Thicky in Thiès district (Senegal) are very abundant and could be used for the production of clay brick for the construction industry in Senegal and the surrounding countries. The geophysical,...Clay materials from Thicky in Thiès district (Senegal) are very abundant and could be used for the production of clay brick for the construction industry in Senegal and the surrounding countries. The geophysical, geotechnical, and thermal studies carried out did lead to a better comprehension of the potential of the area for clay production. It also allowed determining the physical and chemical characteristics of the clays for their use in order to make fired clay bricks. Different types of fired clay brick were produced with Thicky’s clays. The study of the physical, mechanical and thermal parameters of these raw materials and bricks has given very satisfactory results compared to the standards in use. It is noted a good ceramic behavior, and there is no deterioration observed after firing at 900°C until low residual moisture of about 3% (on a dry basis), a smooth texture with a beautiful appearance, a low loss on ignition, a low shrinkage value of less than 1% (dry), moderate water absorption and also good compressive strength. The study of thermal properties on a brick wall by the asymmetric lime plane method gives satisfactory effusivity and thermal conductivity values which are respectively equal to 746.48 J<span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>K<sup>-1</sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>m<sup>-2</sup><span style="white-space:nowrap;">·</span>s<sup>-1/2</sup> and 0.42 W<span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>m<sup>-1</sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>k<sup>-1</sup> with a thermal resistance of 0.0028 m<sup>2</sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>K<span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>W<sup>-1</sup>.展开更多
The use of low thermal conductivity materials plays an important role in the construction of energy-efficient buildings. Indeed, the improvement of the thermal properties of building walls reduces energy consumption. ...The use of low thermal conductivity materials plays an important role in the construction of energy-efficient buildings. Indeed, the improvement of the thermal properties of building walls reduces energy consumption. This study aims to determine the thermal and energy balances of a building enveloped with Typha australis on the one hand, and a building without Typha on the other hand (a building constructed with conventional materials) using the commercial software Visual TTH. The results of the heat loss calculations show that the Typha building is 62% more efficient than the conventional building. Also, the studies on air-conditioning needs resulted in energy savings of 1577.136 kWh per year for the Typha building, i.e. 1219 kg per year of CO<sub>2</sub> avoided in the air according to the SENELEC emission factor 0.773/MWh in Senegal.展开更多
Determining the optical properties of media remains an important part of scientific research. Knowledge of these optical properties, particularly absorption and diffusion coefficients, has direct applications in biome...Determining the optical properties of media remains an important part of scientific research. Knowledge of these optical properties, particularly absorption and diffusion coefficients, has direct applications in biomedical therapeutic diagnostics. The determination of these coefficients was previously reserved for optically dilute media. Recently, a technique called Structured Laser Illumination Planar Imaging (SLIPI) has been developed for measuring extinction coefficients in dense media. For such a medium and technique, no study has reported the determination of absorption and scattering coefficients. In this study, we have developed a simple calculation method based on the combination of Kubelka-Munk relations and extinction, both functions of the medium’s absorption and diffusion coefficients. The equations thus developed enable absorption and diffusion coefficients to be easily calculated from extinction coefficient measurements alone, using the SLIPI technique. The analysis method thus developed was applied to ten (10) milk solutions of different concentrations considered to be predominantly diffusive, and to ten (10) coffee solutions of different concentrations considered to be predominantly absorbent. The coefficient values obtained have been analysed and compared to the literature ones and they would be satisfactory.展开更多
The present work evaluated the properties of modified concrete using polyethylene terephthalate (PET) bottle waste as a partial replacement for coarse aggregate. Modified concrete samples were designed using a water/c...The present work evaluated the properties of modified concrete using polyethylene terephthalate (PET) bottle waste as a partial replacement for coarse aggregate. Modified concrete samples were designed using a water/cement (W/C) ratio of 0.50 and varying percentages of PET replacement (3%, 7%, 10%, and 15% by volume). Dreux Gorisse’s formulation approach was used to make the final products, and the mechanical properties of the samples were determined using Controlab presses. This modified concrete with PET chips has shown that with a 10% replacement of PET chips, the fresh density decreases by 3.56%, and the hardened state density decreases by 2.01%. The water absorption and thermal conductivity of the formulated concretes decreased. However, the results showed that the slump of these fresh concretes increased as the percentage of plastic aggregate replacement increased. Based on the results, incorporating PET aggregates into concrete contributes to good workability, and lightweight concrete structures, and provides some thermal comfort in concrete structures.展开更多
The communication system known as quorum sensing (QS) in gram-negative bacteria regulates biofilm formation and many other functions. The particularity of Pseudoalteromonas ulvae TC14 seems to be the absence of a LuxI...The communication system known as quorum sensing (QS) in gram-negative bacteria regulates biofilm formation and many other functions. The particularity of Pseudoalteromonas ulvae TC14 seems to be the absence of a LuxI inducer, and therefore the lack of production of small molecules of Acyl homoserine lactone (AHL). Previous studies had shown that it does not harbor the inducer of the regulatory molecule (AHL). Nevertheless, it is able to regulate these same functions (biofilm, violacein) via AHLs. This could mean the presence of specific receptors for these induction molecules, belonging to the LuxR family. The aim of this study was to test these hypotheses using molecular analysis. Genome sequencing of the P. ulvae TC14 strain was carried out by Molecular Research LP (MR DNA), using the Illumina Hiseq 2500 method. The results revealed the presence of 2,293,242 base pairs, i.e. 100% of the genomic volume. The number of coding gene sequences was 1983, and the Guanine + Cytosine (G+C) percentage of the base number was 41.55%, revealing stability in the sequenced genome. In order to verify the identity of the sequenced genome, a phylogenetic analysis based on RNA16S was carried out. This analysis resulted in 93% homology with the previously sequenced and characterized species Pseudoalteromonas tunicata, showing that it belongs to the genus Pseudoalteromonas. To these comparative results should be added those derived from genome analysis based on nucleotide percentage using the tools available at https://img.jgi.doe.gov/. The results showed that Pseudoalteromonas tunicata D2 has the highest percentage nucleotide identity (ANI) (75.7913%), followed by Pseudoalteromonas flavipulchra NCIMB2033 (72.2736%) and Pseudoalteromonas phenolica KCTC 12086 (71.6685%). Next, the search for the various genes involved in QS was carried out using sequence comparisons via the BLAST method. For LuxI, sequence templates from the genomes of Vibrio, Chromobacterium, Shewanella or even other Pseudoalteromonas species were screened against the TC14 genome. This yielded no conclusive results synonymous with the non-presence of LuxI in TC14 as assumed by previous research. The search for LuxR, on the other hand, gave rise to the presence of eight presumptive sequences. Molecular characterization of the presumptive LuxR sequences was carried out to assess their gene expression. This characterization showed expression of these LuxR homologous sequences in a range from o.11 to 5.33 picograms (pg). Even if these sequences were not analyzed in depth, the retro-transcription technique nevertheless showed a minimum of activity, which could enable us to distinguish them from inactive sequences. The next step was to compare the LuxRs found in TC14 with the so-called Solo LuxRs, which act autonomously. This study shows that P. ulvae TC14 is a bacterium with a particular LuxR-based communication system.展开更多
The present work investigated the effect of polyethylene terephthalate (PET) plastic waste on the physico-mechanical and thermal properties of cement-stabilized laterite bricks to see the durability of the modified br...The present work investigated the effect of polyethylene terephthalate (PET) plastic waste on the physico-mechanical and thermal properties of cement-stabilized laterite bricks to see the durability of the modified bricks (CSLB). Samples were formulated by mixing laterite, cement, and different percentages of PET (0%, 3%, 5%, and 7%) by volume. The bricks were produced using the M7MI Hydraform standard interlocking block and kept in the shade for a curing period of 28 days. The addition of 3% to 5% PET to the laterite stabilized with 10% cement results in a decrease in both dry and wet compressive strength, which is determined using the Controlab compression machine. However, the obtained results are in concordance with the standards. The thermal conductivity of CSLB, determined using the box method with the EI700 measurement cell, decreases as the PET content of the mixture increases. A decrease in bulk density from 1.67 to 1.58 g/cm<sup>3</sup> was observed.展开更多
Lateritic soils are found over large areas in tropical countries where their suitability for road engineering is a real concern, both compositionally and mechanically. Mineralogical and geochemical characterization, a...Lateritic soils are found over large areas in tropical countries where their suitability for road engineering is a real concern, both compositionally and mechanically. Mineralogical and geochemical characterization, and profile description were carried out on Pliocene gravel lateritic soils from the Thies region to assess their suitability for road construction. These soils were sampled in Lam-Lam, Mont Rolland, Pout, Ngoundiane and Sindia borrow pits in that region. Minerals that make up these studied materials are quartz, kaolinite, hematite and goethite, identified by X-Ray Diffraction and confirmed with Infrared spectroscopy. This mineralogy is characteristic of lateritic soils which are concretionary structure and are formed in well-drained tropical regions like that of Thies. According to the chemical results, these gravel lateritic soils are poor in organic matter, OM 2/(Al2O3 + Fe2O3) Diop ternary diagram for classifying lateritic soils. Therefore, Thies materials are ferruginous lateritic soils, Al2O3/Fe2O3 < 1, containing non-swelling clay (kaolinite) and rich in gravelly nodules, S/CEC < 50wt%. As a result, these soils are compositionally suitable for road construction. These appreciated mineralogical, geochemical and pedological properties can now help overcome compositional challenges well before determining the bearing capacity of lateritic materials. This mechanical strength, which largely depends on their composition, is decisive in defining the optimal conditions for using lateritic materials in road geotechnics.展开更多
Wine & Gourmet Asia 2007(亚洲美食佳酿展暨酒店及餐饮设备展)日前假澳门威尼斯人度假村酒店的会议及展览中心隆重举行。这是一个崭新的贸易、业界交流与厨艺示范平台,举世绝伦地展示了亚太区高级美酒、精致佳肴及酒店服务业的精粹...Wine & Gourmet Asia 2007(亚洲美食佳酿展暨酒店及餐饮设备展)日前假澳门威尼斯人度假村酒店的会议及展览中心隆重举行。这是一个崭新的贸易、业界交流与厨艺示范平台,举世绝伦地展示了亚太区高级美酒、精致佳肴及酒店服务业的精粹,是澳门有史以来最大型的餐饮贸易展。展开更多
文摘Clay materials from Thicky in Thiès district (Senegal) are very abundant and could be used for the production of clay brick for the construction industry in Senegal and the surrounding countries. The geophysical, geotechnical, and thermal studies carried out did lead to a better comprehension of the potential of the area for clay production. It also allowed determining the physical and chemical characteristics of the clays for their use in order to make fired clay bricks. Different types of fired clay brick were produced with Thicky’s clays. The study of the physical, mechanical and thermal parameters of these raw materials and bricks has given very satisfactory results compared to the standards in use. It is noted a good ceramic behavior, and there is no deterioration observed after firing at 900°C until low residual moisture of about 3% (on a dry basis), a smooth texture with a beautiful appearance, a low loss on ignition, a low shrinkage value of less than 1% (dry), moderate water absorption and also good compressive strength. The study of thermal properties on a brick wall by the asymmetric lime plane method gives satisfactory effusivity and thermal conductivity values which are respectively equal to 746.48 J<span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>K<sup>-1</sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>m<sup>-2</sup><span style="white-space:nowrap;">·</span>s<sup>-1/2</sup> and 0.42 W<span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>m<sup>-1</sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>k<sup>-1</sup> with a thermal resistance of 0.0028 m<sup>2</sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>K<span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>W<sup>-1</sup>.
文摘The use of low thermal conductivity materials plays an important role in the construction of energy-efficient buildings. Indeed, the improvement of the thermal properties of building walls reduces energy consumption. This study aims to determine the thermal and energy balances of a building enveloped with Typha australis on the one hand, and a building without Typha on the other hand (a building constructed with conventional materials) using the commercial software Visual TTH. The results of the heat loss calculations show that the Typha building is 62% more efficient than the conventional building. Also, the studies on air-conditioning needs resulted in energy savings of 1577.136 kWh per year for the Typha building, i.e. 1219 kg per year of CO<sub>2</sub> avoided in the air according to the SENELEC emission factor 0.773/MWh in Senegal.
文摘Determining the optical properties of media remains an important part of scientific research. Knowledge of these optical properties, particularly absorption and diffusion coefficients, has direct applications in biomedical therapeutic diagnostics. The determination of these coefficients was previously reserved for optically dilute media. Recently, a technique called Structured Laser Illumination Planar Imaging (SLIPI) has been developed for measuring extinction coefficients in dense media. For such a medium and technique, no study has reported the determination of absorption and scattering coefficients. In this study, we have developed a simple calculation method based on the combination of Kubelka-Munk relations and extinction, both functions of the medium’s absorption and diffusion coefficients. The equations thus developed enable absorption and diffusion coefficients to be easily calculated from extinction coefficient measurements alone, using the SLIPI technique. The analysis method thus developed was applied to ten (10) milk solutions of different concentrations considered to be predominantly diffusive, and to ten (10) coffee solutions of different concentrations considered to be predominantly absorbent. The coefficient values obtained have been analysed and compared to the literature ones and they would be satisfactory.
文摘The present work evaluated the properties of modified concrete using polyethylene terephthalate (PET) bottle waste as a partial replacement for coarse aggregate. Modified concrete samples were designed using a water/cement (W/C) ratio of 0.50 and varying percentages of PET replacement (3%, 7%, 10%, and 15% by volume). Dreux Gorisse’s formulation approach was used to make the final products, and the mechanical properties of the samples were determined using Controlab presses. This modified concrete with PET chips has shown that with a 10% replacement of PET chips, the fresh density decreases by 3.56%, and the hardened state density decreases by 2.01%. The water absorption and thermal conductivity of the formulated concretes decreased. However, the results showed that the slump of these fresh concretes increased as the percentage of plastic aggregate replacement increased. Based on the results, incorporating PET aggregates into concrete contributes to good workability, and lightweight concrete structures, and provides some thermal comfort in concrete structures.
文摘The communication system known as quorum sensing (QS) in gram-negative bacteria regulates biofilm formation and many other functions. The particularity of Pseudoalteromonas ulvae TC14 seems to be the absence of a LuxI inducer, and therefore the lack of production of small molecules of Acyl homoserine lactone (AHL). Previous studies had shown that it does not harbor the inducer of the regulatory molecule (AHL). Nevertheless, it is able to regulate these same functions (biofilm, violacein) via AHLs. This could mean the presence of specific receptors for these induction molecules, belonging to the LuxR family. The aim of this study was to test these hypotheses using molecular analysis. Genome sequencing of the P. ulvae TC14 strain was carried out by Molecular Research LP (MR DNA), using the Illumina Hiseq 2500 method. The results revealed the presence of 2,293,242 base pairs, i.e. 100% of the genomic volume. The number of coding gene sequences was 1983, and the Guanine + Cytosine (G+C) percentage of the base number was 41.55%, revealing stability in the sequenced genome. In order to verify the identity of the sequenced genome, a phylogenetic analysis based on RNA16S was carried out. This analysis resulted in 93% homology with the previously sequenced and characterized species Pseudoalteromonas tunicata, showing that it belongs to the genus Pseudoalteromonas. To these comparative results should be added those derived from genome analysis based on nucleotide percentage using the tools available at https://img.jgi.doe.gov/. The results showed that Pseudoalteromonas tunicata D2 has the highest percentage nucleotide identity (ANI) (75.7913%), followed by Pseudoalteromonas flavipulchra NCIMB2033 (72.2736%) and Pseudoalteromonas phenolica KCTC 12086 (71.6685%). Next, the search for the various genes involved in QS was carried out using sequence comparisons via the BLAST method. For LuxI, sequence templates from the genomes of Vibrio, Chromobacterium, Shewanella or even other Pseudoalteromonas species were screened against the TC14 genome. This yielded no conclusive results synonymous with the non-presence of LuxI in TC14 as assumed by previous research. The search for LuxR, on the other hand, gave rise to the presence of eight presumptive sequences. Molecular characterization of the presumptive LuxR sequences was carried out to assess their gene expression. This characterization showed expression of these LuxR homologous sequences in a range from o.11 to 5.33 picograms (pg). Even if these sequences were not analyzed in depth, the retro-transcription technique nevertheless showed a minimum of activity, which could enable us to distinguish them from inactive sequences. The next step was to compare the LuxRs found in TC14 with the so-called Solo LuxRs, which act autonomously. This study shows that P. ulvae TC14 is a bacterium with a particular LuxR-based communication system.
文摘The present work investigated the effect of polyethylene terephthalate (PET) plastic waste on the physico-mechanical and thermal properties of cement-stabilized laterite bricks to see the durability of the modified bricks (CSLB). Samples were formulated by mixing laterite, cement, and different percentages of PET (0%, 3%, 5%, and 7%) by volume. The bricks were produced using the M7MI Hydraform standard interlocking block and kept in the shade for a curing period of 28 days. The addition of 3% to 5% PET to the laterite stabilized with 10% cement results in a decrease in both dry and wet compressive strength, which is determined using the Controlab compression machine. However, the obtained results are in concordance with the standards. The thermal conductivity of CSLB, determined using the box method with the EI700 measurement cell, decreases as the PET content of the mixture increases. A decrease in bulk density from 1.67 to 1.58 g/cm<sup>3</sup> was observed.
文摘Lateritic soils are found over large areas in tropical countries where their suitability for road engineering is a real concern, both compositionally and mechanically. Mineralogical and geochemical characterization, and profile description were carried out on Pliocene gravel lateritic soils from the Thies region to assess their suitability for road construction. These soils were sampled in Lam-Lam, Mont Rolland, Pout, Ngoundiane and Sindia borrow pits in that region. Minerals that make up these studied materials are quartz, kaolinite, hematite and goethite, identified by X-Ray Diffraction and confirmed with Infrared spectroscopy. This mineralogy is characteristic of lateritic soils which are concretionary structure and are formed in well-drained tropical regions like that of Thies. According to the chemical results, these gravel lateritic soils are poor in organic matter, OM 2/(Al2O3 + Fe2O3) Diop ternary diagram for classifying lateritic soils. Therefore, Thies materials are ferruginous lateritic soils, Al2O3/Fe2O3 < 1, containing non-swelling clay (kaolinite) and rich in gravelly nodules, S/CEC < 50wt%. As a result, these soils are compositionally suitable for road construction. These appreciated mineralogical, geochemical and pedological properties can now help overcome compositional challenges well before determining the bearing capacity of lateritic materials. This mechanical strength, which largely depends on their composition, is decisive in defining the optimal conditions for using lateritic materials in road geotechnics.
