Narrow Results

Proper modeling of the dynamic behavior of the soil significantly affects the accuracy of the soil–structure interaction analysis results. Using nonlinear constitutive models has the highest accuracy in modeling soil behavior under earthquake loading. However, it is not functional for practical engineering purposes because of the high cost and complexity. The equivalent linear method also has many limitations, such as filtering out the high-frequency components of the input excitation, underestimating surface ground motion over long periods, and considerable error in high soil strain levels. The current study aims to present an accurate, simple, and low-cost method to model the nonlinear behavior of clays. This method does not meet the limitations of the traditional methods and fully considers the effect of the influential parameters. The novel central composite design technique was adopted to evaluate the effect of influential variables on the nonlinear behavior of clay and formulate the proposed method. The introduced method is applicable to various building structures, power planets, etc. Numerical analyses performed on the proposed method and nonlinear modeling confirm the accuracy, efficiency, and generality of the proposed method.

The most important decision in cross-docking design is the number of unloading and loading doors. This paper focuses on the design issues of unloading and loading doors of symmetric-I-shaped (I-LTL) cross-docks pervasive in the Chinese auto-part supplying chain which is obviously a very complex system. First of all, this paper analyzes the operation process of I-LTL cross-docking in detail and completes the construction of discrete event simulation that conforms to I-LTL cross-docking operation on the basis of practical details in reality through ARENA platform. In the simulation analysis, this paper selects the physical flow of parts (supporting for arrival frequency and loading capacity of transport vehicles) and I-LTL cross-docking as the simulation experimental factors and applies multilevel factorial design to carry out a large-scale simulation experiment. The results suggest that the required number of receiving dock doors is determined by the arrival frequency of storage vehicles and loading capacity. Moreover, the effect of arrival frequency index is far greater than the loading capacity index. On the other hand, the required number of shipping dock doors primarily depends on the cross-docking consolidation rate and vehicle arrival frequency. Moreover, the index action of consolidation rate is greater than the effect of arriving frequency linearity.

In modern techniques and science one meets design problems for multi-factor experiments in a large experimental region where the underlying model is unknown. These problems needs space filling designs. The uniform experimental design seeks its design points to be uniformly scattered on the experimental domain and is one kind of space filling designs that can be used for computer experiments and also for industrial experiments when the underlying model is unknown. In this paper we shall introduce the theory and method of the uniform design and related data analysis and modelling methods. Applications of the uniform design to industry and other areas are discussed.

Low temperature bonding of two silicon wafers with significant high bond strength has been prepared successfully using sol-gel coating as intermediate layer. The effects of bonding temperature, solution aging time and spin speed on bonding quality have been investigated by a full 2³ factorial design. Under the 75% confidence level, the statistic result shows that only the interaction effect between bonding temperature and spin speed is significant. Design of experiments (DoE) is used to study the effects of key parameters on bond strength, and bonding mechanism are discussed. The possible reason for the observed high bond strength is the absence of absorbed water on the smooth coating surface, which results in the direct condensation reactions between OH groups to form strong Si-O-Si bonds even at low temperatures.

Efavirenz (EFV) suffers from poor aqueous solubility which results in low bioavailability of the drug. Nanocarrier-based drug delivery systems offer a suitable alternative for improving the physico-chemical properties of the drug and hence its efficacy. Nanosuspension (NS) of EFV was formulated by solvent-anti solvent precipitation method using PVP K-30 as stabilizer and sodium lauryl sulphate (SLS) as the wetting agent. Multi-level factorial design was applied to select the optimal formulation which was further characterized. The optimal batch exhibited mean particle size of 305nm and polydispersity index (PDI) of 0.345. Solid-state characterization studies of the NS conducted using scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction, and differential scanning calorimetry (DSC) revealed compatibility between the drug and the excipients and modest alteration in the crystallinity of the drug. There was progressive increase in the solubility of the drug when incorporated in NS from 17.39$\mu$g/ml to 256$\mu$g/ml. Further, drug release studies showed significantly better and controlled drug release pattern in comparison to the free drug due to the presence of nanosized particles in the formulation.

Discrepancy is a kind of important measure used in experimental design. Recently, a so-called discrete discrepancy has been applied to evaluate the uniformity of factorial designs. In this paper, we review some recent advances on application of the discrete discrepancy to several common experimental designs and summarize some important results.

Biologically important molecules have to be crystallized from solution before their atomic structures can be determined. Once their structures have been determined, reliable and fine structural details, which are crucial for structure-based drug design, can be obtained. Crystallization is an important but very poorly understood process. Our inability to produce good quality crystals is a severe limitation of protein crystallography. In this chapter we present rational guidelines which aim to alter our know-how on crystallization from “black magic” into quantitative and affordable science. We have coined a new word, crystallomic, which can be applied to a diverse range of molecules and may intensify research related to crystallogenesis.

Chitin and chitosan hold a great economic value as due to their versatile biological activities and chemical applications, mainly in medical. Recent advances in fermentation technologies suggest that the cultivation of selected fungi can provide an alternative source of chitin and chitosan. The amount of these polysaccharides depends of the fungi species and culture conditions. Filamentous fungi have been considered an attractive source of chitin and chitosan for industrial applications because their specific products can be manufactured under standardized conditions. This research describes an experimental study of the influence of the glucose, thiamine and asparagine concentration on chitin and chitosan production by R. arrhizus. The effect of these factors or the interaction effects between these will be observed by factorial design analysis. For chitin and chitosan production suspensions of 10⁸ sporangioles/mL of R. arrhizus was inoculated in Erlenmeyer flask containg Hesseltine and Anderson medium, varying glucose, thiamine and asparagine concentration. These parameters were varied symmetrically around the central point according to the 2³ factorial design (Glucose 20.0, 40.0 and 60.0 g/L; Tiamine 0.002, 0.005 and 0.008mg/L; Asparagine 1.0, 2.0 and 3.0g/L). An estimate of pure experimental error was calculated from four replicates run corresponding to a central point of the complete factorial. The response recorded were chitin and chitosan yield. The flasks were incubated at 28°C, 150 rpm, during 72 hours. The mycelia were harvested, washed and submitted to lyophilization process. The process of extraction of chitin and chitosan involved deproteination with sodium hydroxide solution, separation of alkali-insoluble fraction, extraction of chitosan by Acetic acid. The degree of deacetylation for chitin and chitosan were determined by infrared spectroscopy. The data were analyzed for significance by the Student’s t-test and chi-square test, using the Statistic program, version 6.0 of Statsoft Inc., USA. The best yield of biomass was obtained in experimental condition 6. (glucose 60.0g/L, Tiamine 0.008 mg/L and asparagine 1.0g/L). On the other hand the best yiels of polysaccharides were obtained in experimental condition 4 (60.0g/L glucose, 0.003mg/L thiamine and 3.0g/L asparatine) for chitosan (96 mg/g) and in experimental condition central point (40.0g/L glucose, 0.005mg/L tiamine and 2.0g/L asparagine) for chitin (202mg/g). There was no statistical difference, 95% significance, between the parameters studied for chitin and chitosan production. The obtained results suggested that the carbon and nitrogen source of the culture medium influence the chitin and chitosan production.