Experimental Investigation on the Behavior of Gravelly Sand Reinforced with Geogrid under Cyclic Loading

In view of the dynamic response of geogrid-reinforced gravel under high-speed train load, this paper explores the dynamic characteristics of geogrid-reinforced gravel under semi-sine wave cyclic loading. A number of large scale cyclic triaxial tests were performed on saturated gravelly soil reinforced with geogrid to study the influence of the number of reinforcement layers and loading frequencies on the dynamic responses of reinforced gravelly sand subgrade for high speed rail track. The variation of cumulative axial and volumetric strains, excess pore pressure and resilient modulus with number of loading cycles, loading frequency, and reinforcement arrangement are analyzed. The test results reveal that the cumulative axial strain decreases as the number of reinforcement layers increases, but increases with loading frequency. The resilience modulus increases with the number of reinforcement layers, but decreases as the loading frequency increases. The addition of geogrid can reduce the excess pore water pressure of the sample, but it can slightly enhance the rubber mold embedding effect of the sand sample. As the loading frequency increases, the rubber mold embedding effect gradually weakens.

An economic valuation of access to cultural institutions: museums, theatres, and cinemas

Cultural institutions are the main beneficiaries of public funds for culture. However, cultural policies suffer from ‘adhocism’ in the administration of institutions, which are often publicly owned and receive little recognition of the benefits that society gains from their use. The aim of this study is to provide the measurement of the use value of access to cultural institutions. Based on the observed individual attendances and their costs, a two-stage budgeting model is employed to estimate the change in consumer surplus related to the loss of access to cinemas, museums, and theatres in Warsaw, Poland. It is the first non-market valuation of cinemas in the existing literature. The inclusion of institutions’ entire markets helps to overcome the bias caused by the embedding effect and the availability of substitutes, which affects many single-site valuations. The estimated use values are compared with the subsidies received by the three groups of cultural institutions. Results reveal substantial benefits provided by cinemas, although cinemas are nearly excluded from the circulation of public support. The estimated use value is enough to justify subsidies for both highly subsidised sectors of museums and theatres. The estimation of use values serves as a starting point for the evaluation of the use of public resources.

Development and Optimization of Attapulgite Clay Based Microencapsulation for Lactic Acid Bacteria by Response Surface Methodology

Lactic acid bacteria (LAB), screened and purified from the fermented yogurt, were microencapsulated in sodium alginate (SA) and attapulgite composite microcapsules by external gelation to increase their viability and stability. Surface characterization by scanning electron microscope clearly evidenced a high number of the LAB embedded in SA/attapulgite composite microcapsules than SA counterparts due to a more cohesive structure, and biocompatible microenvironment. SA/attapulgite and CaCl2/attapulgite composites analysis revealed a better embedding effect of attapulgite blend with SA solvent compared with attapulgite mixed with CaCl2. Influence of three major factors including SA, calcium chloride, and attapulgite concentration on LAB embedding rate were optimized by “single factor strategy” as well as response surface methodology (RSM). Optimal conditions of these factors obtained by RSM were SA (1.03 %), Attapulgite (0.28 %), and CaCl2 concentration (1.17 %). The related embedding rate was predicted as 87.1369 %, and the actual measured value was 91.24 % by experiments using the optimal conditions. In conclusion, the results revealed that LAB microencapsulation in the SA and attapulgite composite might display noteworthy protection against the gastrointestinal environment.

Helical Buckling of Slender Beam Structures Surrounded by an Elastic Medium

ABSTRACTThe goal of this study was to investigate analytically the buckling phenomena of slender beam structures embedded in an elastic medium. In such cases, there is a possibility that spiral-shaped buckling modes can occur due to the restraining effect of the surrounding medium. As a result of analytical investigations, helical buckling occurs radically. Furthermore the pitch of the helix does not fluctuate as the radius of the helix increases. The interesting mechanical implications of the embedding effect are demonstrated by the theoretical approach established in this study.

Evaluation of Different Analysis Methods for the Encapsulation Efficiency of Amylose Inclusion Compound

Recently amylose has drawn much attention as a potential vehicle for the nanoencapsulation of different flavor molecules, and the encapsulation efficiency of the complex is an important index for the evaluation of its embedding effect. In this study, three different methods for assessing encapsulation efficiency of amylose-flavor complexes were compared. We chose heptanol and menthone as the flavor molecules, as both of them exhibit a typical odor. The complexes were prepared by the melting method, and their structures were characterized by XRD. In addition, the encapsulation efficiency was determined by thermal gravimetric analysis (TGA), potentiometric titration (PT), and headspace solid phase microextraction gas chromatography (HS-SPME-GC), respectively. The results showed that PT results were within the reported literature range while HS-SPME-GC seemed to overestimate the results and TGA results were the lowest. What is more, the operations of TGA and PT were relatively simple and the results were reproducible, while the HS-SPME-GC method displayed excellent high sensitivity. Therefore, PT method is the best method for assessing encapsulation efficiency of amylose-flavor complexes.

Embedding Effect on the Mechanical Stability of Pressurised Carbon Nanotubes

We elaborate on the cross-sectional deformation of carbon nanotubes embedded into a self-contracting host medium. The continuum elastic approach is used to formulate the mechanical energy of both the embedded nanotubes and the self-contracting outer medium with finite thickness. Our formula allows us to evaluate the critical radial pressure applied on the interface between the embedded nanotube and the outer contracting medium as well as the deformation mode that arises immediately above the critical pressure. An interesting mechanical implication of the embedding effect, that is, the power-law dependence of the critical pressure on the elastic modulus of the medium, is deduced by the theoretical approach established.