MAIN ENGINEERINGSPROPRETIES OF STABILISED EARTH BLOCK BRICKS FORMULATED WITH SOILS FROM NDJAMENA-CHAD

The most used bricks in house building in NDjamena, city of Chad which is situated in semi dry arid area with 600 millimeters of pluviometry per year and 50 °C as highest temperature, are raw clay bricks, terracotta bricks or bricks in ciment block. The raw clay bricks have strong sensibility in water and weak resistance to compression. The terracotta and cement block bricks have high thermal conductivity contrary to the adobe and their manufacturingcontribute to destroy the environment. The aim of this paper is to search Stabilised Earth Block (SEB) bricks whichare made with clay, sand and few percent of cement and respond to climatic, environmental and economic constraints. Therefore, some bricks are built in mixing differentspercents of sand and clay (M1 : 40% sand and 60% clay, M2 : 50% sand and 50% clay, M3 : 60% sand and 40% clay, M4 : 70% sand and 30% clay, M5 : 30% sand, 30% slime and 40% clay, and M6 : 40 % sand, 20% slime and 40% clay) for obtaining physical stabilizationand adding 8%, 10% or 15% of cementin each type of brick for the chemical stabilization. Theuse of moulding press machine grants already the mechanical stabilization to these bricks. Proctor test has allowedto retain M1, M3 and M4 for searching the best values of the rate absorption of water by capillarity , the resistance in compression and the thermal conductivity of these bricks. The results of tests show bricks M3 with 10% of cement have the good values 21,23 g.cm-².min-1/2 of rate absorption, 3,82 MPa of resistance in compression and 0,5W.m-1.°K-1 as thermal conductivity.

Impact of Gercus Formation Erosion and Rock Sliding on Duhok Dam Reservoir – Northern Iraq

The environmental impact was illustrated by rockslide and erosion on the Duhok Dam and its reservoir. The evaluation of the geotechnical characteristics of the Gercus Formation was conducted. The research plan was divided into three phases, field, laboratory, and office works. The fieldwork included studying all the geological phenomena of the region related to the environmental impact. The laboratory work focused on studying the geotechnical properties of the various rock samples taken from the Gercus Formation. Rocklab program was used to define the geotechnical properties of a rock mass. The results indicated the weak resistance of the Gercus Formation rocks to weathering and erosion processes, as well as their weak resistance to sliding. These results indicate a kind of risk for this formation on the stability of the dam, as well as its effect on the size of the reservoir storage, due to erosion and deposition of huge amounts of sediments in the dam reservoir.

Assessment of the Distribution and Safety of Tetragenococcus muriaticus for Potential Application in the Preparation of Chinese Grasshopper Sub Shrimp Paste

The bacterial profiles of 63 grasshopper sub shrimp paste samples collected from seven typical regions around the Bohai Sea were investigated by high-throughput sequencing. Tetragenococcus muriaticus was found to be the prevailing species present in all the samples, and the presence of T. muriaticus also weakly correlated with the histamine content in the samples. Six T. muriaticus strains with low biogenic amine (BA)-producing ability and deficient in histamine production were identified and subjected to safety assessment. All six strains displayed weak resistance to fifteen known antibiotics as based on the Enterococcus breakpoint values. None of the strains exhibited hemolytic activity or biofilm formation. All strains exhibited were able to grow on MRS agar containing 21% NaCl and expressed amine oxidase and strain-specific proteases and lipases. Most of the strains exhibited acid production at 18% NaCl. Moreover, three of the strains (designated as SG, TS, and QH) with histamine degradation ability were inoculated into separate shrimp paste samples to determine their effect on BA accumulation. The results indicated that the addition of T. muriaticus to shrimp pastes not only led to a significant reduction of BA content in the pastes but also improved the flavor of the pastes. Consequently, these strains may be used as potential candidates for controlling the content of histamine in fermented foods.

Non-disruptive method to decrease stresses in the web of the crane beam

Ensuring the required resource of the bearing capacity of the crane beams is one of the most urgent tasks from the point of view of the rational design. The approach proposed in this article is based on the principle of redistribution of the functions of the elements involved in the operation of the crane structure. Weak resistance to rotation of the top flange and the adjoining web zone is a critical disadvantage of a typical crane structure. Additional reinforce elements are proposed to eliminate the consequences of the influence of this disadvantage. At the same time, these reinforce elements practically do not perceive either the vertical or horizontal components of the crane load, preventing only the rotation of the top flange on the length between the beam stiffeners. Another feature is that no additional stress concentration zones are created either in the flange or in the web from welding or drilling holes. The article provides a comparative analysis of the stress-strain state of the crane beams based on the results of numerical calculations carried out with the use of ABAQUS software package. It is shown that the stresses in the upper zone of the beam web, reinforced by the proposed method, are up to 20% lower than in a conventional I-beam. However, despite the simplicity of the solution, the positive results of numerical analysis and the supposed manufacturability of the approach, it is undoubtedly necessary to conduct a series of full-scale experiments on already existing objects.

Maize (Zea mays L.) Response to Potassium Application and K+ Uptake in the Soil: A Review

Potassium (K) is among the essential macronutrients needed for plant growth and it’s also an extremely dynamic ion in both soil and plant systems. K+ moves intensely in a plant system but moderately in a soil system. The average soil deposits of K generally are plentiful, but their mainstreams are not readily available for crop uptake. Many researches have dealt with the response of crops to potassium application, but few literatures have tackled that of maize to available K and its uptake. This review seeks to discuss current progress concerning the relevance of K in maize crop production and its uptake; how this physiological action transforms into growth and yield. We have reviewed available studies on the content, roles of K in the soil-plant system and factors contributing to K uptake and transportation in plant. Also, the benefits of Potassium Solubilizing Microorganisms (KSMs) as an alternative or in combination with exchangeable K+ are reviewed. Furthermore, K deficiencies in maize causing constraint in physiological activities and rendering weak resistance to pests are also discussed. The current study indicates that intensive agricultural production has led to K nutrient limitation in organic or coarse-textured soil resulting in the reduction of available K reserves. However, an optimal application of K can prevent these fertilization imbalances, which will eventually increase soil fertility.

Resistance to Thiophanate-Methyl in Botrytis cinerea Isolates From Californian Vineyards and Pistachio and Pomegranate Orchards

In this study, a mycelial growth assay was used to evaluate the sensitivity to thiophanate-methyl of 144 Botrytis cinerea isolates (collection A) from Californian vineyards and pistachio and pomegranate orchards. Based on the effective concentration that inhibits 50% of growth (EC50) values for mycelial growth inhibition on fungicide-amended media, 3, 28, 10, and 58% of the isolates showed sensitivity (SS; EC50 < 1 µg/ml), low resistance (LR; 1 < EC50 < 10 µg/ml), weak resistance (WR; 10 < EC50 < 50 µg/ml), and high resistance (HR; EC50 > 100 µg/ml) toward thiophanate-methyl, respectively. The LR and HR phenotypes were observed in pistachio and pomegranate orchards, even though pomegranate was not sprayed with thiophanate-methyl. Sensitivity to thiophanate-methyl of a historical collection of 257 B. cinerea isolates (collection B) isolated from pistachio orchards in 1992, 2005, and 2006 was assessed on potato dextrose agar amended with thiophanate-methyl at the discriminatory concentration of 10 µg/ml. Average percentages of thiophanate-methyl–resistant isolates were 50, 72, and 64% in the orchards in 1992, 2005, and 2006, respectively. A study of fitness components of selected thiophanate-methyl–resistant (LR, WR, and HR) and –sensitive (SS) isolates from collection A did not reveal any significant difference between them with respect to mycelial growth on fungicide-free media and pathogenicity on cultivar Crimson Seedless berries. Comparison of β-tubulin sequences from resistant and sensitive phenotypes revealed that a glutamic acid at position 198 was changed to alanine in all HR isolates and three LR isolates. The occurrence of thiophanate-methyl resistance in B. cinerea populations should be considered when designing spray programs against blossom and shoot blight of pistachio and gray mold of grape.

Applications of nanomaterials in corrosion protection coatings and inhibitors

Various methodologies are practically used to control corrosion. Coatings are the most widely used to protect metals against corrosion. However, due to the weak resistance of polymer coating against the penetration of corrosive solution to the metal/coating interface, the long-term corrosion resistance of the polymer coating is reduced gradually. Recently, nanoparticles have been added to coatings to improve their chemical, mechanical and optical properties. Nanocoatings either have constituents in the nanoscale or are made out of layers that are under 100 nm. Nanocoatings are used effectively to lessen the impact of a corrosive environment due to its various preferences, such as surface hardness, adhesive quality, long haul and, additionally, high-temperature corrosion opposition, and to improve its tribological properties, and so forth. Moreover, nanocoatings can be utilized in more slender and smoother thickness, which permits adaptability in equipment design and lower upkeep and working expenses. This review covers applications related to the management of metal corrosion, including the use of nanomaterials to produce high-performance corrosion inhibitors and corrosion-resistant coatings.

The assessment of erosion in Aoulai watershed (central Rif mountains, Morocco) based on the PAP-RAC guidelines application

The land in the Aoulai watershed in the Rif mountain area of northern Morocco has been deteriorating continually due to several different forms of erosion. The Aoulai watershed is essentially characterized by the domination of weak resistance of the rocky formations and its sensitiveness to other major internal factors that result in a conspicuous impetus for both mass movements and water erosion.Water erosion is seen as the most damaging phenomenon for nature in northern Morocco because it acts as an obstacle to the natural balances and seems to have greater effect on the slopes, through the influence of both human and natural factors. To assess and examine the erosion phenomenon, we have chosen to conduct a qualitative assessment of water erosion in the Aoulai watershed using the PAP-RAC (Priority Actions Programme/Regional Activity Centre) Guidelines. This is the methodology that is most widely applied and implemented both for determining and identifying the areas at risk of erosion and for supporting projects to reduce the degradation that has become a major threat to hydraulic structures including dams, irrigation pipes and other infrastructure elements, which are damaged by the erosion phenomenon in the Central Rif mountains of northern Morocco.

Application of nanomaterials in ultra-high performance concrete: A review

In the recent decades, traditional concrete poses a great challenge to the modernization of the construction industry because of low tensile strength, poor toughness, and weak resistance to cracking. To overcome these problems, ultra-high performance concrete (UHPC) with superior mechanical properties and durability is developed for broad application prospect in the future engineering construction. However, UHPC is less eco-friendly because it consumes more cement compared with the traditional concrete. The manufacturing of cement produces large amounts of carbon dioxide and therefore leads to the greenhouse effect. Nanomaterials consist of microstructural features that range from 0.1 to 100 nm in size, which exhibit the novel properties different from their bulk counterparts, including filling effect, surface activity, and environmental sustainability. This paper reviews the effect of various nanomaterials used in UHPC to partially replace the cement or as an additive on the microstructures, mechanical properties, and other properties of UHPC. In addition, the limitations and shortcomings of the current research are analyzed and summarized, and development directions are provided for future research on the application of nanomaterials in UHPC.