IR spectra and dielectric properties of Cu–Ge ferrite

The mixed ferrite Cu_1+xGe_xFe_2−2xO₄; where x = 0.0, 0.05, 0.1, 0.15, 0.2, 0.25 and 0.3; was prepared from high purity oxides using the standard ceramic technique. The IR spectra were recorded on the range from 200 to 1000 cm⁻¹. The two primary bands corresponding to tetrahedral ν_A and octahedral ν_B were observed around 575 cm⁻¹ and 400 cm⁻¹, respectively. It was found the threshold frequency ν_th for the electronic transition increases with increasing the Ge content. The Debye's temperature θ_D was calculated and it was found dependent on the type of charge carriers. AC conductivity σ_ac with dielectric properties (dielectric constant ?′, dielectric loss ?″ and loss tangent tan δ) as a function of frequency (f = 10² → 10⁶ Hz) at room temperature have been measured. The dispersion of the dielectric properties was discussed in the light of Koop's phenomenological theory.     

Form pressure generated by fresh concrete: a review about practice in formwork design

In this paper, several current industrial practices in formwork design are presented focusing on the normative calculation of the form pressure. Most of the current Standards are devoting for the design of the formwork for the normal vibrated concrete. Currently, the Standards are being updated to include provisions for the newly adapted concrete, such as the flowable concrete and self-consolidating concrete. However, the experience with these methods is still limited. The available methods for calculating the formwork pressure for the flowable concrete and SCC are based on measuring the shear strength of concrete using different concepts, such as the setting time of concrete or the structural build-up at rest. More field work is necessary to validate and provide the confidence to the available methods for the formwork pressure calculation. With this information the regulations could be improved to ensure a more economic formwork design. The paper was discussed within the RILEM TC 233-FPC “Form pressure generated by fresh concrete”.     

Insight into the Structural,Magneto-electronic,and Mechanical Characteristic of Y2MnZ (Z = Al,Ga, In) via DFT Computation

Journal of Superconductivity and Novel Magnetism - The first-principle calculations of density functional theory were used to study the structural, electronic, magnetic, mechanic, and half-metallic...     

Multivariable control of the polymer molecular weight in emulsion polymerization processes

A multivariable control strategy is developed to control the polymer molecular weight in emulsion polymerization processes while maximizing the reaction rate by manipulating the jacket temperature and the monomer flowrate. In order to take into account the process nonlinearity, input-output linearizing control is considered. A cascade of two nonlinear observers is developed to estimate the heat of the reaction and the number of moles of radicals in the polymer particles. By introducing these estimations and the available measurements into the process model, the polymer molecular weight could be estimated online. The online estimation and control strategy was validated experimentally in seeded emulsion polymerization of styrene for which the model of the molecular weight is well known. It was also validated for the methyl methacrylate monomer where a simplified model was identified.     

Overcoming Obstacles to Targeting Muscarinic Receptor Signaling in Colorectal Cancer

Despite great advances in our understanding of the pathobiology of colorectal cancer and the genetic and environmental factors that mitigate its onset and progression, a paucity of effective treatments persists. The five-year survival for advanced, stage IV disease remains substantially less than 20%. This review examines a relatively untapped reservoir of potential therapies to target muscarinic receptor expression, activation, and signaling in colorectal cancer. Most colorectal cancers overexpress M₃ muscarinic receptors (M₃R), and both in vitro and in vivo studies have shown that activating these receptors stimulates cellular programs that result in colon cancer growth, survival, and spread. In vivo studies using mouse models of intestinal neoplasia have shown that using either genetic or pharmacological approaches to block M₃R expression and activation, respectively, attenuates the development and progression of colon cancer. Moreover, both in vitro and in vivo studies have shown that blocking the activity of matrix metalloproteinases (MMPs) that are induced selectively by M₃R activation, i.e., MMP1 and MMP7, also impedes colon cancer growth and progression. Nonetheless, the widespread expression of muscarinic receptors and MMPs and their importance for many cellular functions raises important concerns about off-target effects and the safety of employing similar strategies in humans. As we highlight in this review, highly selective approaches can overcome these obstacles and permit clinicians to exploit the reliance of colon cancer cells on muscarinic receptors and their downstream signal transduction pathways for therapeutic purposes.     

APS 9: an improved adaptive population-based simplex method for real-world engineering optimization problems

The adaptive population-based simplex (APS) algorithm is a recently-proposed optimization method for solving continuous optimization problems. In this paper, a new variant of APS, referred to as APS 9, is proposed to solve engineering optimization problems. APS 9 still follows the main structure of APS where three strategies (i.e., reflection, contraction and local search) can be used to improve the population of solutions. However, the three strategies have been significantly modified and the rules for applying them have been revised. A stagnation detection mechanism and duplicates removal step have been added. The proposed method is compared with the winners of the IEEE CEC 2005 and CEC 2011 competitions on the 22 CEC 2011 problems. The results show the superiority of APS 9 compared to the other two methods. Moreover, APS 9 has been compared with two recent optimization methods on the same test bed. The limitations of the CEC 2011 competition are also discussed and new rules that are more engineering-friendly are proposed.     

Fast synthesis of MgAl2O4‒W and MgAl2O4‒W‒W2B composite powders by self-propagating high-temperature synthesis reactions

MgAl₂O₄?W and MgAl₂O₄?W?W₂B composite powders were obtained rapidly in a single step by self-propagating high-temperature synthesis of WO₃?Mg?xAl₂O₃ and WO₃?B₂O₃?Mg?yAl₂O₃ systems. The addition of various Al₂O₃ contents (x and y-values) to the starting materials was considered as the main synthesis parameter. Thermodynamic calculations revealed that the adiabatic temperature of both systems was decreased with increasing Al₂O₃ content. The XRD results indicated that after acid leaching of the WO₃?Mg?xAl₂O₃ combustion products, W and MgAl₂O₄ were formed as the main phases and WO₂, MgWO₄ and Al₂O₃ as the minor constituents in the final composite. On the other hand, MgAl₂O₄?W composites were synthesized in the WO₃?B₂O₃?Mg?yAl₂O₃ system at y<1.4 mol. By increasing the y-value to 2.1 mol, W₂B was formed as a new product leading to production of MgAl₂O₄?W?W₂B composite. The formation of spinel was confirmed by the Fourier transformed infrared spectroscopy analysis. Microstructure observations represented the uniform distribution of MgAl₂O₄ blocks within the fine spherical W particles. The melting of Al₂O₃ was found as a vital step for rapid synthesis of MgAl₂O₃ by the SHS route. Finally, the possible formation mechanism of MgAl₂O₄ during the combustion synthesis was proposed.     

Antioxidant and antithrombotic effects of green mussels (Perna canaliculus) in rats

In the past decade, the use of marine mussels as seafood is being more popular. They considered being a rich source of various nutritional bioactive compounds that aroused the scientific community's interest. This study investigated the antioxidant and the antithrombotic consequences on Sprague-Dawley male rats after adding dried New Zealand mussel Perna canaliculus in their diet. The biochemical, hematological and histopathological changes were also observed. Forty rats were divided into four groups according to the amount of dried mussels in their diet, in addition to a control group that consumed a basal diet only. Group 1 consumed 25% dried mussels in its basal diet; Group 2 consumed 35% dried mussels in its basal diet, and Group 3 was consumed 45% dried mussels in its basal diet. The biochemical parameters showed improvements in liver function. Interestingly, the lipid profile decreased, especially the low-density lipoprotein cholesterol (LDL-C) levels which were reduced significantly in Group 3 (p < .01). These observations were accompanied by a decrease in iron levels significantly as the amount of dried mussels increased (p < .01). Furthermore, the noticed changes in the hematological profile prove that there is an increase in antithrombotic activity. Dried mussels had potent antioxidant effects in the liver as shown by increased lipid peroxide (p < .05), reduced glutathione (p < .05), and glutathione peroxidase (GSH-Px; p < .05). Additionally, antioxidant activity in the kidney was shown to increase through GSH-Px activity (p < .01). In conclusion, these results indicate that consuming dried mussels resulted in improved biochemical and antioxidants activities and could be used as an antithrombotic agent.     

Lateral solutions for optimizing holding costs in job shops

Queuing networks present as beneficial models for a category of problems emerging in modern manufacturing systems. As the optimal control problem for queuing networks in familiar to be difficult, an important topic of research during the last two decades has been the growth of difficult estimations, and the use of these estimations to control optimal controls. Flexible moderations are an important class of such estimations that have received much consideration in recent years. The central objective of this paper is to determine the utilization of flexible moderations in solving a diversity of scheduling problems. In this paper, we investigate the role of flexible moderations in solving classic job shop problems. For the job shop problem with the objective of minimizing makespan, we build a schedule that is guaranteed to be within a consistent of the optimal. In other words, we examine the job shop scheduling problem with the aim of minimizing holding costs. Recent results show that for this objective, the job shop problem does not have a polynomial time estimation plan; consequently, in terms of approximability, this is a harder objective than the makespan. Our main result is an algorithm, based on regular relaxation that presents lateral optimal schedules.     

Effect of deformation temperature on the mechanical behavior and deformation mechanisms of Al-Al2O3 metal matrix composites

Aluminum-alumina (Al-Al₂O₃) metal matrix composite (MMC) materials were fabricated using the powder metallurgy (PM) techniques of hot pressing followed by hot extrusion. Different reinforcement weight fractions were used, that is, 0, 2.5, 5, and 10 wt% Al₂O₃. The effect of deformation temperature was investigated through hot tensile deformation conducted at different temperatures. The microstructures of the tested specimens were also investigated to characterize the operative softening mechanisms. The yield and tensile strength of the Al-Al₂O₃ were found to improve as a function of reinforcement weight fraction. With the exception of Al-10wt%Al₂O₃, the MMC showed better strength and behavior at high temperatures than the unreinforced matrix. The uniform deformation range was found to decrease for the same reinforcement weight fraction, as a function of temperature. For the same deformation temperature, it increases as a function of reinforcement weight fraction. Both dynamic recovery and dynamic recrystallization were found to be operative in Al-Al₂O₃ MMC as a function of deformation temperature. Dynamic recovery is dominant in the lower temperature range, while dynamic recrystallization is more dominant at the higher range. The increase in reinforcement weight fraction was found to lead to early nucleation of recrystallization. No direct relationship was established as far as the number of grains nucleated due to each reinforcement particle.