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Reactive Powder Concrete (RPC) is recognized as one of the most innovative types of concrete, notable for its exceptional strength and durability. This type of concrete is composed of essential components such as cement, silica fume, quartz powder, silica sand, superplasticizer, and water. Due to its superior mechanical properties, RPC is widely utilized in specialized projects and structures that require outstanding strength and durability. However, the high cost of its components, particularly quartz powder, significantly increases the overall production cost, limiting its widespread application in larger, cost-sensitive projects. Quartz powder is scarce in the Azerbaijan region of Iran and is often sourced from mines in Hamedan and Isfahan. By replacing it with more locally available, affordable materials, final production costs can be reduced. To address this issue and optimize the use of available resources, the possibility of substituting quartz powder with local, cheaper, and more accessible materials has been explored. Micronized quartz powder is crystalline, though some of its finer particles have a minor pozzolanic effect. In contrast, diatomite powder, which contains both amorphous and crystalline particles with a high percentage of amorphous silica, exhibits significantly greater pozzolanic activity. These enhanced reactions contribute to the formation of a denser and stronger concrete matrix, improving its mechanical properties. The purpose of this study was to investigate the feasibility of replacing quartz powder with diatomite powder in different proportions—specifically 25%, 50%, 75%, and 100%. The goal was to evaluate how this substitution affects the concrete's strength while also reducing overall production costs. In this research, concrete samples were tested at various curing ages, including 7, 14, and 28 days. Mechanical tests such as compressive strength and tensile strength were conducted to assess the effects of the substitution on the concrete's performance. Additionally, parameters such as standard water absorption, water absorption during curing, density, and consistency were measured. To simulate real-world construction conditions and avoid the use of specialized equipment, the samples were cured in a water tank at 25°C. This curing method not only eliminated the need for expensive equipment like autoclaves but also made the concrete more applicable to typical site conditions, further lowering production costs. The test results were promising. The strength of the modified concrete mixtures improved significantly when diatomite powder replaced quartz powder. In samples where 100% of the quartz powder was substituted with diatomite, the compressive strength increased from 543 MPa to 806 MPa (approximately 49%), and the tensile strength increased from 543 MPa to 806 MPa (approximately 18%) at 28 days. In addition to the improvements in mechanical properties, the use of diatomite powder offers significant economic advantages. Diatomite is abundantly available in various regions, and its accessibility reduces both production and transportation costs. As a result, the overall production cost of the concrete is significantly lowered, which is especially beneficial for large-scale construction projects where cost efficiency is critical. In conclusion, replacing quartz powder with diatomite powder is a practical solution that brings both technical and economic benefits. The enhanced strength of the concrete, coupled with reduced production costs and the efficient utilization of local resources, makes this approach a practical and effective method for producing high-performance concrete.

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The overarching goal of this research is to use polymeric composites enriched with diatomic soil to improve petroleum-contaminated clayey soil. The effect of petroleum on the geotechnical properties of clayey soil was investigated in the laboratory in the first stage using uniaxial, direct shear, and permeability tests. The polymeric composite material was then created and mixed with the diatomic soil. The geotechnical properties of petroleum-contaminated clayey soil were studied using a polymeric composite material mixed with diatomic soil (PCD). Petroleum reduced the shear resistance, internal friction angle, and uniaxial resistance of the clay for contamination percentages ranging from 0% to 12%. Whereas 12 percent petroleum content causes the greatest changes in soil mechanical resistance. According to the results of the direct shear test, adding 5.5 percent PCD increases the shear resistance of the base material and contaminated base material to average values of 32 and 48 percent, respectively. Furthermore, the results of the petroleum permeability test show that adding 5.5 percent PCD reduces soil permeability. The results show that the improved clay by PCD can be used as a liner for the base of petroleum reservoirs.

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The main diatomic structure-forming species of the Zayandehrud Reservoir was investigated by collecting samples from the surface, five, seven and 10 m depths from January 2011 to October 2012 along four linear transects. Asterionella formosa Hassall, Cyclotella ocellata Pantocsek and Fragilaria crotonensis Kitton were revealed as the three structure-forming species among diatomic algae in the reservoir. The number of these diatomic cells increased from the reservoir banks to its central areas, but their abundance was non-uniformly distributed at the 10-meter water column at different sites, except for C. ocellata that showed a practically uniform distribution at the peak of its maximum growth. Overall, the frequency and cover of these structure-forming diatoms changed under the influence of different abiotic variables such as electrical conductivity (EC) and nitrate (NO₃-N).

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Insecticidal efficacy of three diatomaceous earth (DE) formulations, DEBBM, DEA and F2 was evaluated on three different wheat cultivars, Chamran, Verinak and Behrang, against Tribolium confusum Jacqueline du Val. DEs were applied at the rates of 100, 200 and 300 mg/kg. Bioassays were carried out on wheat at 27 ± 1 °Cand 55 ± 5% RH in continuous darkness. Mortality of adults was counted after 2, 7 and 14 days of exposure. Adults of T. confusum were the most susceptible to DEBBM in Behrang. So that DEBBM concentration of 100 mg/kg after 7 days of exposure caused 98% mortality which reached 100 after 14 days. Therefore, Behrang was the most tolerant cultivar to T. confusum infestations. Furthermore, DEBBM was more effective than the other two testedformulations.  

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Diatoms biosilica shell, frustule, is substitute biostructures to mesoporous silica particles, which possesses their wide surfaces, nano-diameter porosity, mechanical strength, and thermal stability, optical capabilities, and the ability to bind to biomolecules can be used in biosensing applications. In this study, diatom species called Chaetoceros muelleri, was used for the fabrication of the Fe₂O₃-Au-Biosilica magnetic package. After micro-algae cultivation, the synthesis of gold nanoparticles (AuNPs) on silica walls was carried out using the bio-synthesis method, which evaluations have demonstrated the continuous formation of spherical AuNPs on the walls and its surfaces. After this step, the magnetic iron oxide nanoparticles were attached to the silica surface of the diatom, this, in turn, leads to system guiding using a magnetic field. Surface modification of diatoms magnetic complex, by using the APTES, allowed the attachment of fluorescence Rhodamine and the Herceptin antibody (Trastuzumab) to the structure. As well as the attachment of the fabricated system to target cells (SKBR3) was confirmed by fluorescence microscopic analysis. The results of this study indicate the ability and specificity of the diatom silicone shell as a "multipurpose" package for diagnostic and therapeutic activities.

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The main material that causes aggregates to adhere to each other and forms a hard object called concrete is the cement paste. Cement paste consists of cement and water. Obviously, the higher the strength of the cement paste, the ultimate strength of the concrete made from the dough will be high. In this research, an additive material as powdered pumice of Bneh-Kohul mine near Bostan Abad and another additive as Mamaghan diatomite were added to the cement paste. Because these two materials have pozzolanic properties, they will exhibit their cementitious properties in close proximity to our cementitious materials and, as a result, are considered as cement materials. Symptoms related to the naming of different mixture ratios are clearly identified in both tables 4 and 5. In brief, the signs that contain the letter P include Pumice Powder and PD symptoms, including Pumice Powder and Diatomite Powder. The ratio of water to cement materials is considered to be 0.35 and 0.4. The results of the experiments have shown that, in terms of water absorption during treatment, all samples gradually absorb water and also show that hydration reactions of cement materials and the formation of crystals continue to occur regularly. In terms of water absorption of 28-day samples according to the ASTM standard, the results show that the porosity of our dough with different ratios of Pumice Powder  or combination of Pumice Powder and diatomite powder, and this porosity is increased by 0.35% To 0.4%. Water absorption during treatment indicates the progression of hydration reactions. While water absorption of concrete specimens at 28 days of age, according to ASTM C642-06, indicates the internal porosity of concrete, including occlusive bubbles and Capillary tubes. It should be noted that the water density of the gel was higher than that of the ordinary water and was about 1.1, and the density of the molecular water inside the crystals resulting from the hydration reactions was higher than that of the gel water. In terms of the compressive strength of doughs that only have pumice  powder additive, their 28-day compressive strength has a loss of resistance, and also for these samples at 90-day age, a slight drop of resistance is observed for the water-to-cement ratio of 0.35 However, for the 0.4% cement ratio, about 10% increased resistance. In the samples that were added to the pumice powder and diatomite powder as additive, the compressive strength changes were as follows: a) for the water-to-cement ratio of 0.35 at the age of 28 days and 90 days, an average increase of 6% Resistance is present and increases resistance for the optimum additive (25%).
b) For water-cement ratio 0.4% at 28 days for 20% additive of compound powder, compressive strength reduction is noticeable, but in the 90-day life it is 5% stronger and for 25% additive compound powder at the age of 28-day and 90-day, both increase in compressive strength of 9% and 16%, respectively. Therefore, adding of the combined of Bostan Abad Pumice Powder and Diatomite Powder is recommended.