Constrained Consequence

There are various contexts in which it is not pertinent to generate and attend to all the classical consequences of a given premiss—or to trace all the premisses which classically entail a given consequence. Such contexts may involve limited resources of an agent or inferential engine, contextual relevance or irrelevance of certain consequences or premisses, modelling everyday human reasoning, the search for plausible abduced hypotheses or potential causes, etc. In this paper we propose and explicate one formal framework for a whole spectrum of consequence relations, flexible enough to be tailored for choices from a variety of contexts. We do so by investigating semantic constraints on classical entailment which give rise to a family of infra-classical logics with appealing properties. More specifically, our infra-classical reasoning demands (beyond a\modelsb{\alpha\models\beta}) that Mod(β) does not run wild, but lies within the scope (whatever that may mean in some specific context) of Mod(α), and which can be described by a sentence ·a{\bullet\alpha} with b\models·a{\beta\models\bullet\alpha}. Besides being infra-classical, the resulting logic is also non-monotonic and allows for non-trivial reasoning in the presence of inconsistencies.     

Doubly Reinforcing Cementitious Beams with Instrumented Hollow Carbon Fiber Tendons

Surface mounted strain gages are used to characterize the behavior of polymer-enhanced cementitious beams designed to withstand reverse loadings. These unique composite structures are doubly reinforced with hollow carbon fiber (graphite) tendons equipped with strain gages and the study includes section design, materials considerations, structural testing, and finite element analysis. The primary purpose of strain gage integration is to insure that the stress in the materials remains within the elastic range so that damage does not occur. A finite element model is developed to characterize the structural response in the elastic range and a hybrid approach is suggested in which displacement, strain, and stress can be obtained with a single strain gage. The ability to characterize structural performance beyond the elastic range is also demonstrated by analyzing data obtained from displacement-controlled tests.     

Observation of ordered phases of fullerenes in carbon nanotubes

We have assembled molecular arrays of C60 inside double-walled carbon nanotubes (DWNTs) with internal diameters of 11-26 A and directly observed the existence of different crystalline phases of C60 previously predicted theoretically. The structure of the encapsulated C60 crystal is defined by the internal diameter of the DWNT, as the molecules adjust their packing arrangement in order to maximize van der Waals interactions. We have also shown that fullerenes in C(60)@DWNT interact with the outer layer of DWNTs, as demonstrated by the efficient filling of DWNTs with internal diameters of less than 12 A.     

A multipoint method for detecting coherent features in a turbulent shear flow

A technique is presented for the computer detection of temperature fronts in a turbulent shear flow. The detection variable is the product, averaged over a given duration, of temperature fluctuations at a given number of spatial locations. Efficient algorithms are developed for computing the product and for determining accurately the instants of detection, aided by simulations, using model temperature fronts. Ensemble averages of temperature and velocity are obtained for the self-preserving region of a turbulent plane jet.     

Wei-type duality theorems for matroids

We present several fundamental duality theorems for matroids and more general combinatorial structures. As a special case, these results show that the maximal cardinalities of fixed-ranked sets of a matroid determine the corresponding maximal cardinalities of the dual matroid. Our main results are applied to perfect matroid designs, graphs, transversals, and linear codes over division rings, in each case yielding a duality theorem for the respective class of objects.     

Designs from subcode supports of linear codes

We present new constructions of t-designs by considering subcode supports of linear codes over finite fields. In particular, we prove an Assmus-Mattson type theorem for such subcodes, as well as an automorphism characterization. We derive new t-designs (t ≤ 5) from our constructions.      

SPECTRAL QUALITY OF TWO FLUORESCENT UV SOURCES DURING LONG-TERM USE

The characteristics of a fluorescent ultraviolet (UV) lamp (UVB-313), UV-B transmitting cellulose diacetate (CA) and UV-B absorbing polyester (PE) films were determined during actual use. Although lamp emission was stable between 70 and 386 h of burn time (longer times were not investigated), the absorbance of UV-B and UV-A radiation by CA and PE films, respectively, increased with time when wrapped around lamps. As a result, the irradiance of lamp/filter combinations decreased steadily (even when CA films were presolarized for 10 h), making it necessary to compensate by adjusting the height of the lamp bank or by changing filters frequently. Note that corrective action is required for UV-A controls (PE films) as well as UV-B experimental treatments (CA films). Changing filters is preferable, since aging of CA filters caused shifts in the ratio of UV-B to UV-A. However, in spite of these shifts, the normalized spectrum of weighted biologically effective UV-B radiation did not change to a large extent.