Introduction: Consumption of sugar rises worldwide every year resulting in increasing dental health issues, such as dental caries. Dental caries arise from sugar metabolism, which is carried out by pathogenic bacteria living in a human's mouth, and insufficient dental hygiene. The WHO report from 2022 states that 2 billion adult people and 514 million children are stricken by caries of teeth. In dental caries treatment, contaminated tissue must be removed and the resulting cavity is usually filled with a composite material having a dimethacrylate matrix. Commercially available dimethacrylate monomers give dental materials proper physicochemical properties and support their mechanical properties. However, they do not provide antibacterial activity. This problem can be solved by the application of monomers with quaternary ammonium (QA) groups. The positively charged QA group interacts with the negatively charged surface of bacteria cells, which leads to bacteria death. Current research concerning monomers with QA groups shows that they are effective against bacteria, however, do not ensure optimum performance characteristics of composite dental materials.

Aim of the research: Achievement of a novel urethane-dimethacrylate monomer with two QA groups (QAUDMA) for possible application in dentistry.

Results: QAUDMA was synthesized from 2-(methacryloyloxy)ethyl-2-decylhydroxyethylmethylammonium bromide and commercial diisocyanate.

Aim of presentation: Presentation of the chemical structure of novel QAUDMA, and its synthesis route, supported with detailed 1H and 13C NMR and FTIR analyses.

The binomial distribution is the probability distribution of the number of successes for a sequence of n independent trials with success probability p. Efficiently generating binomial random variates is important in many modeling and simulation applications, such as in medicine, risk management, fraud and anomaly detection, among others. A variety of algorithms exist for generating binomial random variates. This paper concerns the algorithm chosen for rho mu, an open source Java library for efficient randomization. In rho mu, I implemented a hybrid of two existing binomial random variate algorithms. For most cases, rho mu's hybrid relies on the BTPE Algorithm (Binomial, Triangle, Parallelogram, Exponential), and falls back to the inverse transform for cases that BTPE cannot handle. BTPE uses rejection sampling, and BTPE's authors originally provided an analytical formula for the expected number of iterations in terms of n and p. That expression is complicated to interpret in practical contexts. I explore BTPE by instrumenting rho mu's implementation to empirically analyze its acceptance/rejection behavior to gain further insight into its runtime performance. Although the number of iterations depends upon n and p, my experiments show that the average number of iterations is always under 2, and that the average number of random uniform floats required to generate a single random binomial is under 4 (2 per iteration). Thus, when analyzing the runtime of a simulation algorithm that includes steps generating random binomials, one can consider such steps to have a constant runtime.

The aim of this study was to investigate some chemical and microbiological characteristics of the soil and the surface biofilm of both polypropylene microplastics and quartz sand. The exposure of sterile samples lasted for 30 days in the soil of a residential area. Some initial chemical and microbiological characteristics of the soil were studied, as well as microbiological characteristics of the biofilm on the surface of materials. This expands the understanding of biofilm formation processes on the surface of microplastics in soil and can be used in processes for removing harmful materials from soil.

A key factor in ensuring the stability and ductility of asphalt pavements is interlayer fatigue resistance. interlayer bonding characteristic is one of important factors that impacts the asphalt pavements service life. Poor bonding properties frequently result in de-bonding, slippage cracking, and pavement deformation. Interlayer slippage cracking commonly develops from a lack of interface bonding between an asphalt overlay and underlayer, which is typically due to the braking and turning of the vehicle. Emulsified asphalt, modified asphalt, and hot asphalt are just a few of the compounds that are utilized as tack coatings to fix the problem. In this paper, five distinct bonding types between interlayers are examined—a model with no tack coat, with SBS-modified hot asphalt, with SBS-modified asphalt emulsion, with an epoxy resin binder and with SK-90 hot asphalt. This study evaluates cyclic load, tension damage under the asphalt pavement, and shear fatigue at various load cycles to examine the shear fatigue. A model is created using the Abaqus software to anticipate fatigue life while taking into account the various tack coat materials listed above, and from there, the best bonding type for asphalt pavement is selected. After choosing the material, various take-coat thicknesses were used until the optimum size was decided upon for pavement design. The suggested model can withstand more cycles of the load, sustain less tension damage, and respond well to cyclic loading to prevent interlayer fatigue failure over the course of a pavement's design life.

Climate changes, especially global warming, are observed due to greenhouse gases released on an industrial scale. For this reason, progress is being made around the world to reduce CO2 emissions and transition to sustainable energy sources. One of the most matured methods of capturing CO2 from flue gases in industrial sectors is chemical absorption. This work analyzed the absorption process in capturing CO2 from the flue gases of a 1 Mt cement plant. The Aspen Plus modeling package was used to simulate the flue gas pre-treatment, absorption column, and regeneration unit. As a result of the modeling, optimal values of column sizes, heat duty, and solvent make-up that require the least capital and operational costs for capturing CO2 in the flue gases of this plant were determined. When a 40% MEA solution is used and the CO2 loading in the absorption-stripping process is 0.25 mol/mol, the reboiler heat duty is 4.06 MJ/kg CO2.

Daily maximum (T_max) and minimum air temperature (T_min) are sensitive to the soil moisture status and land surface parameterization. However, this topic has not been investigated in arid regions (e.g., Egypt). To address this issue, four 13-year experiments were conducted using a regional climate model (RegCM4). The first two considered the soil moisture status (bare soil versus global satellite soil moisture product; ESACCI). The other two considered the sensitivity to the two land surface schemes coupled to the RegCM4: Biosphere Atmosphere Transfer System (BATS) and version 4.5 of the community land model (CLM45). In all simulations, the RegCM4 was downscaled by the Era-Interim reanalysis with 25 km grid spacing. The simulated T_max and T_min were evaluated with respect to the Climate Research Unit (CRU) and station data.

Results showed that switching from bare soil to ESACCI has a considerable influence on the simulated T_max and T_min. Furthermore, the CLM45 outperforms the BATS with respect to the CRU. Concerning T_max, such behavior is obviously noted in the coasts of the Mediterranean and Red Sea. Overall of Egypt, the CLM45 has potential skills more than the BATS particularly in the inland regions. In comparison with the observed data, behavior of the BATS/CLM45 varies with the location and month. Despite of the noted biases, the RegCM4 can be recommended for future studies concerning the seasonal prediction or climate change of Egypt as long as it is configured with the CLM45 land surface model and initialized with the ESACCI satellite moisture product.

Particle characterization is critical in industries that are influenced by particle size distribution. Understanding particle behavior is critical for product quality control and manufacturing process optimization. Particle features, such as size and shape, significantly affect material performance and properties. This review paper examines the importance of particle characterization in many industries and focuses on particle size and shape measurement. The paper begins by delving into particle size and size distribution analysis, emphasizing the impact of particle size on material properties and the many methodologies used for particle size analysis. The paper then examines particle shape characterization and its impact on material characteristics. It gives an overview of particle characterization techniques and the criteria for selecting the best technique for a given sample. Particle characterization in ceramics, food, cosmetics, medicines, and metallurgy is also thoroughly investigated. Overall, this work emphasizes the importance of particle characterization in numerous industries and provides insights into particle size and shape measurement.

Fabricating conformal cooling channels (CCCs) has become easier and more cost-effective because to recent advances in additive manufacturing. CCCs give better cooling performance than regular (straight drilled) channels during the injection molding process. The main reason for this is that CCCs may follow the paths of the molded shape, but regular channels cannot. CCCs can be used to decrease thermal stresses and warpage while also decreasing cycle time and producing a more uniform temperature distribution. Traditional channels, on the other hand, have a more involved design technique than CCC. Computer-aided engineering (CAE) simulations are crucial for establishing an effective and cost-effective design. The goal of this paper is to compare two ANSYS modules for the purpose of verifying findings. For models with fine mesh, the two modules appear to provide equivalent results. As a result, the ANSYS module to use should be determined by the job's purpose as well as the complexity of the CAD geometry.

Analytical modelling of thin-film, multilayered piezoelectric microcantilevers is presented in this work. Piezoelectric microcantilevers are used in these chemical sensors. Different types of probe coatings are applied to these types of microcantilevers. A Position-Sensitive Sensor (PSS) system is used to identify chemical ingredients in the materials with high sensitivity, and external voltage is measured in mV. The maximum voltage generated for the sensor is 39 mV. This range of voltage is suitable for sensing electronic systems. An angle change of a microcantilever in a liquid or gas environment identifies a material's chemical ingredients. A microcantilever deflects, resulting in varying voltages to analyze materials. COMSOL software and equations are used for analytical simulations to determine optimal design parameters. COMSOL software model development and MEMS design are involved in analytical simulations. This paper examines the analytical model of the cantilever and discusses the fabrication process.

Providing accurate information of potential evapotranspiration (PET) is mandatory for arid regions (such as Egypt) for assessing the crop water requirements. Such precision is limited by the dynamical downscaling options and the physical settings used in regional climate models (like RegCM4). To address these issues, four simulations were run as part of the current study. The first two simulations take direct (DIR) and one-way nesting (NEST) into account, while the other two use two boundary layer techniques (HOLTSLAG; HOLT) and (University of Washington; UW). All simulations were driven by ERA-Interim reanalysis of 1.5 degrees. The simulated PET was evaluated with respect of high-resolution reanalysis gridded derived product of the ERA5-Land (hereafter ERA5).

The findings revealed that while there is no discernible difference between DIR and NEST in terms of the global incident solar radiation (RSDS). Also, NEST has a higher mean air temperature (TMP) than DIR. Additionally, UW has a lower TMP than HOLT, but switching between HOLT and UW did not impose a considerable impact on the simulated RSDS. Concerning PET, it is affected neither by switching between DIR and NEST or between HOLT and UW. Such results suggest that the RSDS is the main driver in controlling the PET variability followed by TMP. Therefore, using the DIR downscaling option and HOLT/UW boundary layer scheme throughout the 1980–2010, as recommended by the World Meteorological Organization, the RegCM4 model can be used to develop a regional PET map of Egypt.