The Food Diversity and Choices of Archachatina Marginata raised in Concrete Trench Pens

Archachatina marginata is an economically useful gastropod, scientifically proven to be of huge benefit to human’s health and wellbeing. Food varieties of A. marginata hunted from the immediate environment of Ovia North East, South-South, Nigeria, were investigated to select the most appropriate, in terms of preferences and availability. The study was conducted for five months (May to August, 2020) during the rainy season. Ten snails were selected from the wild with weights ranging from 340.21g to 355.32g and heights of 11.8cm to 13.3cm at the point of collection. The snails were housed each, in an escape-proof trench pen, covered with wire gauze and nylon net. They were fed with fourteen different types of food materials (water leaves, paw-paw leaves, sweet potato, white -boiled rice, corn powder, ripe paw-paw fruit, cocoyam leaves, millet powder, water melon, cucumber, formulated poultry mash, pineapple, white paper and cabbage). Water melon was very well consumed by all the snails (1323.30g; 66.17%) compared to other food items. The least consumed food items were millet powder (19.99%) and pineapple (20.28%). There was a marked increase in weight and length of the snails as the months progressed, with average length of 15.01 cm and average weight of 501.58g in August, relative to the initial measurements in May.

Filter Characteristics of Porous Wire Gauze Partitions

The article presents the results of experimental studies of the uneven distribution of the distances between the wires of the warp and weft in woven wire meshes with square cells used to clean gases and liquids from mechanical impurities in various branches of technology. On the basis of experimental data using the methods of probability theory, the regularity of the size distribution of the cells of these grids is determined. The length of its minimum side is chosen as the determining size of a square cell. The results of the conducted studies were used to estimate the fractional coefficient of the leakage of spherical particles through the mesh in the sieve mechanism of separation of these particles from the fluid flow. The probability of particle breakthrough through the grid is assumed to be equal to the fraction of the fluid flow passing through the cells, which determines the size of which is larger than the particle diameter. For experimental verification of the calculated values of the leakage coefficient for the sieve filtering mechanism, a preliminary analysis of the influence of the parameters of the hydrodynamic mode of fluid flow through the grid and the level of fluid contamination on the filtering mechanism was carried out. The results of experimental studies of the fractional leakage coefficient values obtained by the sieve filtering mechanism are compared with the calculated data.

Predicting the Pressure Drop of Corrugated Sheet Structured Packings in Deep Vacuum Applications

Advanced corrugated sheet structured packings are considered a natural choice for<br /> deep vacuum distillation. In many of these applications that occur at absolute pressures<br /> below 0.01 bar at the top of the column, the low density gas/vapor driven by pressure<br /> ascends through an irrigated packed bed under laminar flow conditions. This implies that the packing geometry features aiming to reduce the form drag of advanced packing may not be as effective, if at all, as experienced in common applications where turbulent flow prevails. To consider this appropriately, a theoretically founded expression for laminar flow friction factor has been incorporated into Delft model (DM). With this extension, the predicted pressure drop within laminar flow region approaches closely that estimated using well-established empirical model available in software package SULCOL. In absence of adequate experimental evidence, extended DM was validated using newest data obtained at FRI with an advanced wire gauze structured packing in total reflux experiments carried out with paraxylene/orthoxylene system at 0.02 and 0.1 bar top pressure in a column with internal diameter of 1.22 m.