Monopoly Distortions in Durability and Multi-Dimensional Quality

I show that Swan’s (1970) independence result requires a multiplicative interaction between durability and all other quality attributes. Because there is no compelling argument for a multiplicativity in quality, monopolists tend to distort durability, even with constant marginal costs. Distortions in durability and other quality aspects are aligned exactly when the marginal cost of quality do not increase too much with durability

Theoretical backgrounds of durability analysis by normalized equivalent stress functionals

Generalized durability diagrams and their properties are considered for a material under a multiaxial loading given by an arbitrary function of time. Material strength and durability under such loading are described in terms of durability, safety factor and normalized equivalent stress. Relations between these functionals are analysed. We discuss some material properties including time and load stability, self-degradation (ageing), and monotonic damaging. Phenomenological strength conditions are presented in terms of the normalized equivalent stress. It is shown that the damage based durability analysis is reduced to a particular case of such strength conditions. Examples of the reduction are presented for some known durability models. The approach is applicable to the strength and durability description at creep and impact loading and their combination

Collusion and Durability

We develop a model to show that cartels that produce goods with lower durability are easier to sustain implicitly. This observation gen- erates the following results: 1) implicit cartels have an incentive to pro- duce goods with an inefficiently low level of durability; 2) a monopoly or explicit cartel is welfare superior to an implicit cartel; 3) welfare is non-monotonic in the number of firms; 4) a regulator may demand inefficiently high levels of durability to prevent collusion

Evaluation of Fly Ash Concrete Durability Containing Class II Durability Aggregates, July 1986

Fly ash was used in this evaluation study to replace 15% of the cement in Class C-3 concrete paving mixes. One Class "c" ash from Iowa approved sources was examined in each mix. Substitution rate was based on 1 to 1 basis, for each pound of cement removed 1.0 pound of ash was added. The freeze/thaw durability of the concrete studied was not adversely affected by the presence of fly ash. This study reveals that the durability of the concrete test specimens made with Class II durability aggregates was slightly increased in all cases by the substitution of cement with 15% Class "c" fly ash. In all cases durability factors either remained the same or slightly improved except for one case where the durability factor decreased from 36 to 34. The expansion decreased in all cases

Fatigue strength and durability analysis by normalised equivalent stress functionals

Generalised fatigue durability diagrams are considered for a material under multi-axial loading given by a (non-regularly) oscillating function of time. Phenomenological strength conditions under such loading are presented in terms of the normalised equivalent stress functionals both for quasi-ductile rupture and brittle fracture. Examples of the functionals are presented for some known and new durability models including those sensitive to the load sequence. Some complex strength conditions applicable to the durability description at fatigue, creep, dynamic loading and their combinations are presente

On the Growth and Stability Effects of Habit Formation and Durability in Consumption

This paper shows that a unique balanced growth monetary equilibrium exists in a transactions-based monetary endogenous growth model with habit formation or durability in consumption. An increase in the nominal money growth rate reduces the long-run output growth rate, wherein habit formation enforces the effectiveness of monetary policy while durability in consumption reduces it. We also show that while habit formation destabilizes the macroeconomy by making the balanced growth equilibrium exhibit local indeterminacy, durability in consumption maintains saddle-path stability of the balanced growth equilibrium. We find that the mechanism through which habit formation and durability impose different effects on both the growth-effect of money and the macroeconomic stabilizing properties is such that habit formation and durability influence the elasticity of intertemporal substitution in consumption in opposite directions.Habit formation, Durability, Superneutrality, Indeterminacy

Durability of Igbokoda Clay and Silica Sand as a Synthetic Moulding Sand

Mechanical test experiments have been performed on the synthetic mould sand made from the clay and silica sand obtained from lgbokoda in Ondo State, Nigef1a, to determine its durability of use. The synthetic moulding sand was further admixed with sodium carbonate, cassava flour and coal dust additives in an attempt to enhance the clay bonding properties. After each casting, the synthetic moulding sand was re-used and this was repeated several times. This paper reports the result of the mechanical properties obtained and hence the durability of the synthetic moulding sand. The results showed that the lgbokoda clay-bonded-silica sand has very good durability up to five times re-use. There was improved mechanical properties/durability when the additives were used. Castings made during the experimental period were sound. The additives gave improved bonding propert

Collusion and Durability

We develop a model to show that cartels that produce goods with lower durability are easier to sustain implicitly. This observation gen- erates the following results: 1) implicit cartels have an incentive to pro- duce goods with an inefficiently low level of durability; 2) a monopoly or explicit cartel is welfare superior to an implicit cartel; 3) welfare is non-monotonic in the number of firms; 4) a regulator may demand inefficiently high levels of durability to prevent collusion.cartels; collusion; durability