The use of sand deposits in buildings for energy storage

The aim of the research is to prepare data for the design of heat stores with sand filling. In buildings without basement, spaces between foundation walls are filled with material easily compacted, which forms a solid and durable basis for the ground level of the building. As a rule, this material is sand of various grain size, and foundation walls are insulated. In this way, a space filled with a granular material is formed, which, with a properly designed heat exchanger attached, may be used as sensible-heat storage. Such a store makes a good lower level source for heat pumps - source of heat at the time of low temperatures outside, which significantly raises the coefficient of efficiency of the system. Low construction cost of the heat exchanger is an additional argument for the use of the space between the foundation walls for the purpose of building a heat store. This paper presents the results of studies that allow of the appropriate design of the heat exchanger in a heat store with a granular deposit. The deposit temperature changes in time have been studied, dependent on the distance from the source of heat and humidity of the material. Study was carried out for the sands used for filling the space between the foundation walls.

Avalanches overflowing a dam: dead zone, granular bore and run-out shortening

The influence of a dam on granular avalanches was investigated. Small-scale laboratory experiments were designed to study the effectiveness of dams built to protect against large-scale dense snow avalanches. These experiments consisted of releasing a granular mass that first flowed down an inclined channel, then hit and overflowed a dam spanning the channel exit and finally spread out on an inclined unconfined run-out zone. First, we measured the volume retained upstream of the obstacle and the overrun length downstream of the obstacle. In the avalanche regime studied here, no simple relation was found between the volume retained and the run-out shortening resulting from the obstacle. The results highlighted that the avalanche run-out was also shortened by complex local energy dissipation. Second, we report the study of the granular deposit propagating upstream of the dam. We show that there was a change in behaviour from an overflow-type regime for low dam heights to a bore regime for higher dam heights. Finally, we show that this change in behaviour directly influenced the local energy dissipation and the resulting avalanche run-out shortening downstream of the dam.

Channelized free-surface flow of cohesionless granular avalanches in a chute with shallow lateral curvature

A series of laboratory experiments and numerical simulations have been performed to investigate the rapid fluid-like flow of a finite mass of granular material down a chute with partial lateral confinement. The chute consists of a section inclined at 40° to the horizontal, which is connected to a plane run-out zone by a smooth transition. The flow is confined on the inclined section by a shallow parabolic cross-slope profile. Photogrammetric techniques have been used to determine the position of the evolving boundary during the flow, and the free-surface height of the stationary granular deposit in the run-out zone. The results of three experiments with different granular materials are presented and shown to be in very good agreement with numerical simulations based on the Savage–Hutter theory for granular avalanches. The basal topography over which the avalanche flows has a strong channelizing effect on the inclined section of the chute. As the avalanche reaches the run-out zone, where the lateral confinement ceases, the head spreads out to give the avalanche a characteristic ‘tadpole’ shape. Sharp gradients in the avalanche thickness and velocity began to develop at the interface between the nose and tail of the avalanche as it came to rest, indicating that a shock wave develops close to the end of the experiments.

Electrodeposition in support: concentration gradients, an ohmic model and the genesis of branching fractals

The technique of paper-supported copper electrodeposition provides examples of well-presented fractal and dense radial structures. The growths may be developed to reveal concentration gradients around the growths at low cell overpotential. Measurements for current and length scale against time, within a mid-range of cell overpotentials, fit an ohmic model of the growth conditions. To examine the relation of growth morphology to the micrometre-scale structure, we grew first at one overpotential and then continued at a lower overpotential. Electron microscope observations of this growth reveal a distinct change in microstructure from irregular to dentritic microcrystalline from the high to low potential respectively. The interface between the growths is a distinctive compact granular deposit. The granular deposit is unstable to branching and dendrite growth.

Fine structure of the suberized cell walls in the boundary zone and necrophylactic periderm in wounded peach bark

Bark on the scaffold limbs of 6-year-old peach (Prunus persica (L.) Batsch cv. Redhaven) trees was mechanically wounded and tissue samples for ultrastructural study were taken after 6, 8, 12, and 14 days. Examination with light and fluorescence microscopy revealed lignification of boundary zone cell walls after 6 days followed by suberization of the lignified cell walls after 8 days. Necrophylactic periderm was present by day 12 and, by day 14, three to five cells of the new phellem were observed. Examination of tissues with transmission electron microscopy revealed suberin lamellae on the inner wall of boundary zone cells. These cells contained senescing cytoplasm with fragments of undifferentiated dense material that formed a thin, discontinuous granular deposit inside the suberin layer. Suberin lamellae did not occlude plasmodesmata. Cells of the new phellem were radially compressed, heavily suberized, and lacked pits or plasmodesmata.

Scanning electron microscope observations of internal symptoms of white elm following Ceratocystis ulmi infection and cerato-ulmin treatment

Internal vascular symptoms induced by Ceratocystis ulmi infection and cerato-ulmin (CU) in white elm (Ulmus americana) were observed under a scanning electron microscope. Symptoms caused by CU were indistinguishable from those caused by C. ulmi. The main symptoms observed were (i) edemalike surface wall alteration, (ii) granular deposit, (iii) pit membrane heaving, (iv) smooth coating, (v) bubble and (or) tylose formation, (vi) rough coating, (vii) droplet formation, and (viii) vessel plugging with calluslike material. Internal symptoms appeared earlier in CU treated elms (as early as 2 h after treatment) than in C. ulmi infected elms (10 h after infection).

TYPES OF THE PYRENOMYCETE GENERA HYMENOPLEELLA AND LEPTEUTYPA

Hymenopleella sollmannii n. nom. (≡Sphaeria hippophaës Sollmann non Hymenopleella hippophaës (Fabre) Munk) was found to have unitunicate asci with a pulvillus, and a ring that turns blue in iodine. Isolates made from the triseptate, terete, brown ascospores produced pycnidia with annellophores bearing usually four-septate conidia with three brown cells and hyaline end cells each furnished with one short central seta. A comparison with Lepteutypa fuckelii (Nitschke) Petrak revealed that it is readily distinguished by the ascospores, which are narrower, octagonal in section, and furnished with a granular deposit in the middle line of the septa.