172 research outputs found
Understanding time-inconsistent heterogeneous preferences in economics and finance:A practice theory approach
Sorry, Your Order Has a Substitution : The Effects of Substitution Policy in Online Grocery Retailing
Post-purchase out-of-stock (OOS) often happens in an online store context, where products appear to be available at the time a consumer makes an order and checks out, but then become OOS when the order is to be dispatched. To mitigate negative responses from consumers, online grocery retailers often provide consumers a substitution alternative to the OOS item. This paper investigates the effects of two substitution policies where we focus on different matching strategies of the substitution with the OOS item. In policy one, we measure the effect of matching on the dominant attribute (brand vs. flavour). In policy two, we test the effect of matching with a product from the consumers’ past purchase portfolio. We investigate these two substitution policies and their interaction in two categories that differ on the level of differentiation (i.e., the degree to which distinctions are objectively measurable – vertical differentiation/VD vs. not easy to evaluate – horizontal differentiation/HD). Our dependent variable is the probability to accept the substitute. The study employs a computer-simulated purchase experiment, using two product categories: margarine (VD) and cereals (HD). 2,113 UK consumers representative of general UK shopper profile participated. Findings show that in the margarine category where brand is the dominant attribute, the same brand substitution is more likely to be accepted than the same flavour substitution. In contrast, in the cereal category where flavour is more likely to be the dominant attribute, same flavour substitution is more likely to be accepted than same brand substitution. The results also show that, in both categories, matching the substitution product with a product from consumers’ past purchase portfolio is more likely to be accepted than offering a substitute that consumers have not bought before. We also found a significant interaction between the two policy types but for cereals only. The effects of two substitution policies are mediated by perceived fairness of the substitution. The paper discusses contributions and implication for future research
Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world
Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic.
Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality.
Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States.
Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis.
Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection
Thermal elastic-plastic stress analysis of symmetric aluminum metal-matrix composite laminated plates under uniformly distributed temperature
In this study, a thermal elastic-plastic stress analysis is carried out on simply supported symmetric cross-ply (0degrees/90degrees)(2) and angle-ply (5degrees/85degrees)(2), (15degrees/-15degrees)(2), (30degrees/-30degrees)(2), (45degrees/-45degrees)(2), (60degrees/60degrees)(2), (15degrees/60degrees)(2), (15degrees/75degrees)(2), (75degrees/-75degrees)(2) aluminum metal-matrix laminated plates under the uniform temperature distribution across the thickness of the plates. The Tsai-Hill criterion is used as a yield criterion. Differential equations are solved with a sufficiently large number of integration intervals of the temperature. The composite material is assumed to be strain hardening linearly. The magnitude of the residual stress components in the cross-ply laminated plate are higher than those in the angle-ply laminated plates. Plastic yielding occurs in all the laminated plates at the same temperature
Elastic-plastic stress analysis of a thermoplastic composite disc under linear temperature distribution
WOS: 000235778200004In the present study, an elastic-plastic stress analysis is carried out on a composite thermoplastic disc reinforced by steel fibers, curvilinearly. Radial and tangential stresses are obtained under a liner temperature distribution. The magnitude of the tangential stress component for elastic and elastic-plastic cases is higher than that of the radial stress component. The tangential stress component is compressive and tensile on the inner and outer surfaces, respectively and is the highest on the inner surface. The elastic-plastic solution is performed for the plastic region expanded around the inner surface by an analytical formulation and a numerical solution. The solution is also carried out by the finite element method (ANSYS solution). These two solutions give very similar results. The intensities of the residual stress component of the tangential stress and plastic flow are the highest at the inner surface
Elastic-plastic stress analysis of simply supported and clamped aluminum metal-matrix laminated plates with a hole
In this study, an elastic-plastic stress analysis is carried out on simply supported and clamped cross-ply and angle-ply aluminum metal-matrix composite laminated plates with a circular hole. Classical lamination theory with first-order shear deformation theory is used for small deformations. The expansion of the plastic region and residual stress components are obtained on the upper and lower surfaces of the plates by using the finite element method. They are loaded on the upper surface transversely. Loading is gradually increased from the yield point of the plate by 0.0001 MPa at each load step. Load step numbers are chosen as 400, 600 and 800. (C) 2001 Elsevier Science Ltd. All rights reserved
An elastic/plastic solution for a thermoplastic composite cantilever beam loading by bending moment
In this study, an elastic/plastic stress analysis is carried out for a thermoplastic composite cantilever beam loaded by a bending moment at the free end. The composite beam is reinforced by woven steel fibers, at 0, 15, 30 and 45 degrees orientation angles. An analytical solution is performed for satisfying both the governing differential equation in the plane stress case and boundary conditions for small plastic deformations. The solution is carried out under the assumption of the Bernoulli-Navier hypotheses. It is found that the intensity of the residual stress component of sigma (x) is a maximum at the upper and lower surfaces. The composite material is assumed to be as hardening linearly. The Tsai-Hill theory is used as a yield criterion. (C) 2000 Elsevier Science Ltd. All rights reserved
Elastic-plastic stress analysis of simply supported and clamped thermoplastic composite laminated plates loaded transversely
In this study, an elastic-plastic stress analysis is carried out on simply supported and clamped cross-ply and angle-ply steel fiber reinforced thermoplastic composite laminated plates under transverse loading. Classical lamination theory with first order shear deformation theory are used for small plastic deformations. The orientation angles are chosen as [0degrees/90degrees](2), [30degrees/-30degrees](2), [45degrees/-45degrees](2), [60degrees/-60degrees](2) for symmetric and antisymmetric cases. Loading is gradually increased in sequence of 100, 300 and 500. The expansion of the plastic region and the residual stress components are obtained by using the finite element technique
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