Given a BIBD(v,k,A) we can construct a directed BIBD(v,k,A*) by writing each block of the BIBO twice, the second time in the reversed order. Here we prove the analagous expected but useful result that if a BIBD(v,b,r ks,k,A) exists, then a RCOBIBD(v,k,A *} also exists. A nonexistence result is also given.

In this paper an attempt is made to offer insights into local slope failure mechanisms from the perspective of hydrogeology. The hypothesis examined envisages that the hydraulic conductivity distribution in a weathered profile includes a relatively high hydraulic conductivity zone associated with the jointed rock mass near rockhead. There is evidence locally for such a condition. The groundwate...

The Barkhausen pattern from the amorphous alloy Fe21Co64B15 showed high sweep-to-sweep reproducibility for most sweeps when driven slowly over a minor hysteresis loop. Small changes in the maximum applied field led to completely different pulse patterns. When driven near saturation the sweep-to-sweep reproducibility was lost. Large features observed on rapid sweeps were also reproducible, but n...

To compare the velocity characteristics of wheelchair propulsion with and without the use of a tennis racquet, eight male wheelchair tennis players performed a series of 20m sprints from a stationary start. The maximum velocities reached on average 4.39 ± 0.74 m/s; however, they were reduced by 0.18 ± 0.06 m/s during the racquet condition. Furthermore, when wheeling under the racquet condition,...

In this article, we develop a set of partial differential equations describing the flow of a dusty fluid in variable porosity media. The developed equations take into account the effect of the porous microstructure on the flowing phases. We presented and overview of the equations governing the flow of a dusty gas in various type media, including that in naturally occurring porous media. Numeric...

PAF-16 which is based on tetrahedral units (TCPSi) and triangular building units, shows both high thermal stability and high chemical stability. The surface area of PAF-16 can be tuned by changing the reaction temperature and ratio of monomer and catalyst. PAF-16 also shows considerable adsorption capacity of CO(2).

The whole class of minimally coupled and massive scalar fields which may be responsible for flattening of galactic rotation curves is found. An interesting relation with a class of scalar-tensor theories able to isotropise anisotropic models of Universe is shown. The resulting metric is found and its stability and scalar field properties are tested with respect to the presence of a second scala...

As an important two-dimensional material which shows exceptional mechanical and chemical stability, superior electronic properties, along with broad applications, the hexagonal-BN (h-BN) has drawn great attention recently. Here we report a systematic study on the structural stability, electronic and magnetic properties of various h-BN edges, including both bare and hydrogen-terminated ones. It ...

We introduce a model for the classical synchronised multiple access system with a single transmission channel and a randomised transmission protocol (ALOHA). We assume in addition that there is an energy harvesting mechanism, and any message transmission requires a unit of energy. Units of energy arrive randomly and independently of anything else. We analyse stability and instability conditions...

The application of convolution potential voh.ammetry to questions of metal complexation is described. Theoretical relations are derived to show that the stability constants may be directly related to the shift in the peak potential of the semiderivative wave, provided the complexes are labile. Equations are also given for inert and quasilabile complexes. Stability constants for the PbCI, and Cd...