Modelling the shear-tension coupling of woven engineering fabrics

An approach to incorporate the coupling between the shear compliance and in-plane tension of woven engineering fabrics, in finite-element-based numerical simulations, is described. The method involves the use of multiple input curves that are selectively fed into a hypoelastic constitutive model that has been developed previously for engineering fabrics. The selection process is controlled by the current value of the in-plane strain along the two fibre directions using a simple algorithm. Model parameters are determined from actual experimental data, measured using the Biaxial Bias Extension test. An iterative process involving finite element simulations of the experimental test is used to normalise the test data for use in the code. Finally, the effectiveness of the method is evaluated and shown to provide qualitatively good predictions

Transact taxes in a price maker/taker market

We develop a price maker/taker model to study how a financial transaction tax affects markets. We find taxes widen quoted and effective spreads by more than twice the tax. Taxes increase volatility slightly (without intermediation) to significantly (with intermediation). High taxes may halve volumes and gains from trade while doubling search costs. Measures of market quality are more affected by taxes in markets with intermediaries. Investors and intermediaries competing for liquidity can triple search costs and increase quoted spreads while decreasing effective spreads. We also find revenue-optimal rates of 60-75 bp. Our results are particularly relevant to markets with high-frequency trading or thin depth

COMSOL’s New Thermoacoustics Interface and Computationally Efficient Alternative Formulations for FEM

Three efficient alternatives to the model in COMSOL’s thermoacoustics interface are presented. The higher efficiency of these models are explained from theory and are demonstrated by means of two examples

The Uncertain Legacy of Gilmer: Mandatory Arbitration of Federal Employment Discrimination Claims

The United States Supreme Court in Alexander v. Gardner-Denver Co. held that an employee could not be forced to arbitrate his discrimination claim against an employer pursuant to his union\u27s collective bargaining agreement. Subsequent cases viewed Gardner-Denver as prohibiting mandatory arbitration in employment discrimination claims, until the Supreme Court upheld an agreement to submit all statutory discrimination claims to arbitration in Gilmer v. Interstate/Johnson Lane Corp. Gilmer seems to have limited the prohibition of mandatory arbitration in Gardner-Denver to collective bargaining agreements. Subsequently, many lower courts interpret Gilmer as an approval of arbitration clauses in employment agreements, and as such, employers have increasingly included these compulsory arbitration clauses in employment contracts and applications. However, there is still varied treatment of mandatory arbitration clauses by courts. The note explores court decisions which treated subsequent congressional legislation as barring such agreements, additional safeguards imposed by some circuit courts regarding mandatory arbitration agreements, the principal arguments in favor of such agreements, and the countervailing arguments, most represented by the stance of the Equal Employment Opportunity Commission (EEOC). The note concludes by arguing that the United States Supreme Court should clarify the issue in favor of mandatory arbitration agreements, but require that arbitration proceedings from such agreements incorporate fundamental procedural protections for employees, as opposed to the present scheme in which arbitrators do so only on a voluntary basis

Retirement Responses to Early Social Security Benefit Reductions

This paper evaluates potential responses to reductions in early Social Security retirement benefits. Using the Health and Retirement Study (HRS) linked to administrative records, we find that Social Security coverage is quite uneven in the older population: one-quarter of respondents in their late 50's lacks coverage under the Disability Insurance program, and one-fifth lacks coverage for old-age benefits. Among those eligible for benefits, respondents who subsequently retired early appear quite similar initially to those who later filed for normal retirement benefits, but both groups were healthier and better educated than those who later filed for disability benefits. Next we investigate the potential impact of curtailing, and then eliminating, early Social Security benefits. A life-cycle model of retirement behavior provides estimated parameters used to simulate the effects of cutting early Social Security benefits on retirement pathways. We find that cutting early Social Security benefits would boost the probability of normal retirement by twice as much as it would the probability of disability retirement.

Social Security Replacement Rates for Alternative Earnings Benchmarks

Social Security reform proposals are often presented in terms of their differential impacts on hypothetical or ‘example’ workers. Our work explores how different benchmarks produce different replacement rate outcomes. We use the Health and Retirement Study (HRS) to evaluate how Social Security benefit replacement rates differ for actual versus hypothetical earner profiles, and we examine whether these findings are sensitive to alternative definitions of replacement rates. We find that workers with the median HRS profile would be estimated to receive benefits worth 55% of lifetime average earnings, versus 48% for the SSA medium scaled profile. Since US policymakers tend to prefer a replacement rate measure tied to workers’ own past earnings, using these metrics would yield higher replacement rates compared to commonly used scaled illustrative profiles. However, benchmarks that use population as opposed to individual earnings measures to compare individual worker benefits to pre-retirement consumption produce lower replacement rates for HRS versus hypothetical earners.

Pion double charge exchange on 4He

The doubly differential cross sections for the $^4$He$(\pi^+,\pi^-) 4p$ reaction were calculated using both a two-nucleon sequential single charge exchange model and an intranuclear cascade code. Final state interactions between the two final protons which were the initial neutrons were included in both methods. At incident pion energies of 240 and 270 MeV the low-energy peak observed experimentally in the energy spectrum of the final pions can be understood only if the contribution of pion production is included. The calculated cross sections are compared with data.Comment: 25 pages, 9 figure

Support of the collaborative inquiry learning process: influence of support on task and team regulation

Regulation of the learning process is an important condition for efficient and effective learning. In collaborative learning, students have to regulate their collaborative activities (team regulation) next to the regulation of their own learning process focused on the task at hand (task regulation). In this study, we investigate how support of collaborative inquiry learning can influence the use of regulative activities of students. Furthermore, we explore the possible relations between task regulation, team regulation and learning results. This study involves tenth-grade students who worked in pairs in a collaborative inquiry learning environment that was based on a computer simulation, Collisions, developed in the program SimQuest. Students of the same team worked on two different computers and communicated through chat. Chat logs of students from three different conditions are compared. Students in the first condition did not receive any support at all (Control condition). In the second condition, students received an instruction in effective communication, the RIDE rules (RIDE condition). In the third condition, students were, in addition to receiving the RIDE rules instruction, supported by the Collaborative Hypothesis Tool (CHT), which helped the students with formulating hypotheses together (CHT condition). The results show that students overall used more team regulation than task regulation. In the RIDE condition and the CHT condition, students regulated their team activities most often. Moreover, in the CHT condition the regulation of team activities was positively related to the learning results. We can conclude that different measures of support can enhance the use of team regulative activities, which in turn can lead to better learning results

Valuing and Pricing Retail Leases with Renewal and Overage Options

We consider retail leases with landlord overages options, with tenant renewal options, with both and with neither. We illustrate how the ratio of initial expected sales to the sales threshold can be manipulated to equate the value of the landlord overage options to that of the tenant renewal option at the same initial rent. As a result, not only are the values of the dual option overage plus renewal lease and no option leases are equal, but the cumulative distributions of potential IRRs on the two leases are nearly identical, suggesting that these leases are equally attractive to risk-adverse investors and thus that the same risky discount rate can be used in valuing the leases. The analysis is carried out in a risk-neutral framework, and sensitivity of the results to interest rate uncertainty, real sales volatility and growth, and the required risk premium on retail real estate is shown. The appropriate risky discount rate for the overage lease is calculated to be 75 to 160 basis points greater than that for the renewal lease.