Similarity solutions of a strong shock wave propagation in a mixture of a gas and dusty particles

The similarity solutions of a strong shock wave propagation in a mixture of a gas and small solid particles have been investigated. Similarity solution exists only when the shock is very strong and the surrounding medium is of a constant density and at rest and with negligible counterpressure. The non-dimensional fundamental equations are derived and studied. The results depend on three non-dimensional parameters; i.e. (i) the ratio of the specific heats of the gas γ, (ii) the mass concentration of the solid particles k_p in the mixture and (iii) the ratio of the density of the solid to that of initial density of the gas G. Numerical solutions for various values of γ k_p and G are presented and discussed. The speeds of the shock wave front and its location with various energy releases are given.     

The peripheral pulse following arterial injury

There has been little attention paid to the persistence of the pulse following complete forearm arterial transection, and we found no report that has established the etiology or frequency of this phenomenon. Eighteen patients with documented complete radial or ulnar artery transections were evaluated. Nine of the 18 patients had persistently palpable pulse distal to the transections. Seven of the pulses were due to retrograde flow and two were due to transmission from the proximal arterial stump or large collaterals. The Allen test was accurate in demonstrating arterial occlusion in each case. Digital compression of the intact artery eliminated the pulse in those cases due to retrograde flow. Documentation of flow direction and collateral vessels was performed with the Doppler directional velocity meter. The fallibility of the peripheral pulse following complete arterial injury is stressed. The Allen test, digital compression of the intact artery, and Doppler studies should be performed on patients with suspected arterial injuries. The exploration of all wounds in the region of major arteries from which profuse bleeding has occurred is recommended.     

Properties of an intense 40-kV neutral beam injector

The properties of an intense neutral beam injector, the modified duoPIGatron ion source, are discussed and compared with other injectors. For this source (a) beam composition for hydrogen is approximately (85+/-5) % monatomic, (b) nucleon gas efficiency is 50%, (c) the electrical efficiency of ion generation is 1.1 A/kW, and (d) up to 52% of the input power is delivered in the ion and neutral beam to a target subtending a half angle of 1.8 degrees x1.4 degrees .     

Utilization of lignins in rubber compounding

Lignin in the form of lignosulfonate containing about 33% moisture was found to be dispersible in natural rubber by dry mixing. Properties such as tear resistance, abrasion resistance, flex crack resistance, and crack growth resistance improved upon addition of lignin, irrespective of the nature of filler added. This lignin was found to have negative effects on modulus, tensile strenght, resilience, heat buildup, and compression set, which showed, however, remarkable improvement upon aging.     

Regularization Approaches to Demosaicking

Demosaicking is the process of reconstructing a full resolution color image from the sampled data acquired by a digital camera that apply a color filter array to a single sensor. In this paper, we propose a regularization approach to demosaicking, making use of some prior knowledge about natural color images, such as smoothness of each single color component and correlation between the different color channels. Initially, a quadratic strategy is considered and a general approach is reported. Then, an adaptive technique is analyzed, in order to improve the reconstruction near the edges and the discontinuities of the image. This is performed using a novel strategy that avoids computational demanding iterations. The proposed approach provides good performances and candidates itself for many applications. Moreover, since the response of the pixel sensors can be taken into account, it can handle nonideal acquisition devices.     

Processes controlling the thermal regime of saltmarsh channel beds

Spatially and temporally continuous temperature measurements were collected over 32 h using a fiber-optic distributed temperature sensing (DTS) system deployed along 330 m of two intertidal saltmarsh channel beds in northern California. Measured temperature gradients imparted ecosystem-scale structure to the saltmarsh tidal channel thermal regime, which was punctuated by potential warm and cold refugia. Anomalous bed temperatures of 2-4 degrees C occurred throughout the 1.3 tidal cycles at some locations. Discrete locations of consistently warm temperatures characterized sustained seepage of recently infiltrated tidal waters. Low-variance temperature anomalies were typically collocated with hidden microtopographic tributaries that facilitated mixing of warm surface waters and cold groundwater. Bed temperature gradients (approximately 2 degrees C/100 m, average) decreased from high temperatures similar to bay water at the channel mouths to low inland temperatures comparable to groundwater. The trends were maintained by cold groundwater discharge throughout the channels, which affected bed temperatures in proportion to channel reach exposure time; the opposing effect, conductive bed-warming by tidal waters, was proportional to flood duration. DTS is a promising tool for identifying spatial and temporal temperature patterns of hydroecological importance amidst complex natural systems.