Experimental Study on Mechanical Properties of Self-Compacting Recycled Concrete

The application of self-compacting recycled concrete can solve the problem of environmental pollution caused by construction waste but its mechanical properties have not been unified and need further study.The strength of recycled concrete is unstable,and its performance still needs further study.The combination of fixed sand and stone volume method and free water cement ratio method is used to determine the mix ratio of self-compacting recycled concrete.24 sets of slump expansion tests and 24 sets of cube axial compression tests were carried out to study the effect of recycled aggregate replacement rate on the flow performance and axial compressive strength of self-compacting recycled concrete,and the performance conversion formula of self-compacting recycled concrete was given.The results show that with the increase of the regenerated coarse aggregate substitution rate,the fluidity and filling property of the self-compacting regenerated concrete mix decreased.The failure of self-compacting recycled concrete is mainly due to the failure of strength between old mortar and new mixture.As the substitution rate increases from 0 to 100%,the axial compressive strength decreases by 15.2%.

Research on the impact of pension income and expenditure patterns on the pension replacement rate of public institutions

Currently in China, to study the replacement rate of pension reform in public institutions and to find out the key problems, which is of practical significance for the reform of the pension insurance system. In this paper, the impact of pension income and expenditure patterns on the substitution rate is analyzed, and the factors that affect the level of substitution rate are analyzed, and the corresponding policy recommendations are put forward.

Substitution Marginal Rate and Its Usage in the Marginal Preference Calculation

The slope of indifference curve is known as a marginal rate of substitution （MRS）. MRS defining ratio always describes slope of indifferent curve, i.e. MRS matches the module of indifferent curves slope. Utility function U（Xl,X2） is used to calculate marginal rate of substitution （MRS）, because MRS gives the slope of appropriate indifference curve, it can be interpreted as a norm, in which costumer is ready to substitute good 1 by small amount of good 2. The word ＂marginal＂ in economic means ＂differential＂. Here we have partial differentiation, because in time of calculation of good l＇s marginal utility the amount of good 2 remains the same. We can calculate MRS in two ways using differential and function. In the first case consider change （akl,ak2） during which utility is unchanged. For the second method let the curve of indifference present by x2 （X1） function. The function shows how many of x2 is needed for each unit of xl to stay on this concrete curve of indifference. We obtain two equations for the term of MRS and budget constraint and two xl and x2 variables. To define the optimal choice of x1 and x2 as a function of the price and income, we need to solve those two equations. The problem of maximization can be solved by using differential.

Study on the alternative rate of rural residents＇ pension and the mechanism of financial allocation

According to the China Statistical Yearbook divided eight consumption expenditure, I set food, clothing, housing and household equipment and services as residents basic living expenses, of China＇ s rural pension replacement rate level of demand is calculated. The financial revenue scale autoregressive model predicted 2010-2020, the scale of fiscal revenue, with Pratt ＆ Whitney type total pension should be of basic pension and substitution rate level of demand for pension accounts for fiscal revenue proportion of the international experience of fiscal income of 5% were measured and evaluated. The current basic pension in the short term to improve the life of the rural elderly has an important role, but the long-term need to continue to increase, should optimize the structure of fiscal expenditure.

Strength and Microstructural Analysis of Geopolymer Prepared with Recycled Geopolymer Powder

The strength and microstructural analysis of recycled geopolymer are presented in this paper.Five kinds of geopolymers containing 0%,20%,50%,80%and 100%of recycled geopolymer powder were prepared using metakaolin as the source material.The alkali activator solution was a mixture of sodium silicate(Na_(2)SiO_(3))and 12 M sodium hydroxide(NaOH).The change laws of compressive and flexural strength of recycled geopolymer specimens were investigated.And the microscopic characteristics were carried out by SEM,XRD and FTIR to observe the internal morphology and analyze changes in components of recycled geopolymers at different substitution rates.The results show that,with the increase of substitution rate of recycled geopolymer powder,the mechanical properties of recycled geopolymers degenerate and the looser structure are formed.When the substitution rate is less than 50%,the recycled geopolymer specimen meets the use requirements of heavy traffic load class.And the specimen with 80%of substitution rate satisfies the requirements of plastering mortar.

An assessment of Charter airline benefits for Port Elizabeth and the Eastern Cape

Tourism is becoming a vital component for economic development in South Africa. The income generated by the tourism industry is about 6% of the GDP, which is significant but still falls short of the goal set by the White Paper on Tourism in 2000. In the light of South Africa hosting the 2010 Football World Cup, it is important to identify ways of sustainable tourism development that would continue to increase the benefits to the economy long after the event＇s over. The main objective of the research was to explore an idea for increasing the level of tourist income generated in the Port Elizabeth （Eastern Cape） area. The idea was researched by means of conducting a cost-benefit analysis of two tourist related projects. These projects would introduce Charter airline services between Europe and Port Elizabeth. A second objective was to identify constraints on the project or market failures which would prevent their implementation. The economic theory behind the operation of an airline showed that lease costs and aeroplane operating costs are the two most important factors determine Charter airline＇s profitability. In order to offset these costs, airlines must achieve high passenger load factors. Charter airlines have the advantage over scheduled airlines, in that they will only fly if a minimum level of people has pre-booked seats. Two aeroplanes were chosen for comparison purpose： an Airbus A 340-300 and a Boeing 767-300ER. The private benefits calculated were based on load factors between 80 and 95 percent for ticket prices of USD 667 and USD 773. In addition, to private costs and benefits, social benefits were also estimated in the form of additional secondary revenue generated. With the introduction of net social benefits, both projects become profitable. A 50 percent substitution of revenue generated by the Charter tourists reduces the profits for the both projects drastically. A project based on a Boeing 767-300ER is the most efficient project as it has the highest NPV and BCR values. A reduction in the lease cost of the Airbus 340-300 could make projects based on it more competitive. A few constraints on the establishment of a Charter airline operator based in Port Elizabeth are： the lack of adequate runway for the landing of the long-haul carriers and the need of a larger liberalisation of the aviation policy by eliminating protectionism. The cost benefit analysis undertaken in this research does not take into account social costs and benefits to the economy of establishing a Charter airline based in Port Elizabeth, such as an employment, infrastructure development and poverty alleviation. Nevertheless the analysis does suggest that there are strong private and social benefits warranting the establishment of an airline business between Europe and Port Elizabeth. The economic benefits of the tourism industry and its link to airline travel are outlined in section 3. It is shown that the growth of the airline industry is a major component and contributor to tourism growth.

How Do Variable Substitution Rates Influence Ka and Ks Calculations?

The ratio of nonsynonymous substitution rate （Ka） to synonymous substitution rate （Ks） is widely used as an indicator of selective pressure at sequence level among different species, and diverse mutation models have been incorporated into several computing methods. We have previously developed a new γ-MYN method by capturing a key dynamic evolution trait of DNA nucleotide sequences, in consideration of varying mutation rates across sites. We now report a further improvement of NG, LWL, MLWL, LPB, MLPB, and YN methods based on an introduction of gamma distribution to illustrate the variation of raw mutation rate over sites. The novelty comes in two ways： （1） we incorporate an optimal gamma distribution shape parameter a into γ-NG, γ-LWL, γ-MLWL, γ-LPB, γ-MLPB, and γ-YN methods; （2） we investigate how variable substitution rates affect the methods that adopt different models as well as the interplay among four evolutional features with respect to Ka/Ks computations. Our results suggest that variable substitution rates over sites under negative selection exhibit an opposite effect on estimates compared with those under positive selection. We believe that the sensitivity of our new methods has been improved than that of their original methods under diverse conditions and it is advantageous to introduce novel parameters for Ka/Ks computation.

Optimal Investment Strategy of Defined Contribution Pension Based on Bequest Motivation and Loss Aversion

Under the S-shaped utility of loss aversion,this paper considers the bequest motivation of pension plan participants,random salary income before retirement and the substitution rate between receiving pension benefits after retirement and wages before retirement,and studies the optimal investment strategy of defined contribution(DC)pension.Assuming that pension funds can invest in a financial market consisting of three assets(risk-free asset cash,rolling bonds and stocks),inflation is considered by discount.Under the S-shaped utility,the Lagrange method is used to find the terminal optimal surplus of pensions in retirement,so as to find the terminal optimal wealth,and then the martingale method is used to find the optimal wealth process and investment strategy.Finally,a sensitivity analysis is carried out on the the influence of bequest motivation and loss aversion on the optimal investment strategy of DC pension.

Evidence that Natural Selection is the Primary Cause of the Guanine-cytosine Content Variation in Rice Genes

Cereal genes are classified into two distinct classes according to the guanine-cytosine （GC） content at the third codon sites （GC3）. Natural selection and mutation bias have been proposed to affect the GC content. However, there has been controversy about the cause of GC variation. Here, we characterized the GC content of 1 092 paralogs and other single-copy genes in the duplicated chromosomal regions of the rice genome （ssp. indica） and classified the paralogs into GC3-rich and GC3-poor groups. By referring to out-group sequences from Arabidopsis and maize, we confirmed that the average synonymous substitution rate of the GC3-rich genes is significantly lower than that of the GC3-poor genes. Furthermore, we explored the other possible factors corresponding to the GC variation including the length of coding sequences, the number of exons in each gene, the number of genes in each family, the location of genes on chromosomes and the protein functions. Consequently, we propose that natural selection rather than mutation bias was the primary cause of the GC variation.