Assessing the microbiota of recycled bedding sand on a Wisconsin dairy farm

Background:Sand is often considered the preferred bedding material for dairy cows as it is thought to have lower bacterial counts than organic bedding materials and cows bedded on sand experience fewer cases of lameness and disease.Sand can also be efficiently recycled and reused,making it cost-effective.However,some studies have suggested that the residual organic material present in recycled sand can serve as a reservoir for commensal and pathogenic bacteria,although no studies have yet characterized the total bacterial community composition.Here we sought to characterize the bacterial community composition of a Wisconsin dairy farm bedding sand recycling system and its dynamics across several stages of the recycling process during both summer and winter using 16S rRNA gene amplicon sequencing.Results:Bacterial community compositions of the sand recycling system differed by both seasons and stage.Summer samples had higher richness and distinct community compositions,relative to winter samples.In both summer and winter samples,the diversity of recycled sand decreased with time drying in the recycling room.Compositionally,summer sand 14 d post-recycling was enriched in operational taxonomic units(OTUs)belonging to the genera Acinetobacter and Pseudomonas,relative to freshly washed sand and sand from cow pens.In contrast,no OTUs were found to be enriched in winter sand.The sand recycling system contained an overall core microbiota of 141 OTUs representing 68.45%±10.33%SD of the total bacterial relative abundance at each sampled stage.The 4 most abundant genera in this core microbiota included Acinetobacter,Psychrobacter,Corynebacterium,and Pseudomonas.Acinetobacter was present in greater abundance in summer samples,whereas Psychrobacter and Corynebacterium had higher relative abundances in winter samples.Pseudomonas had consistent relative abundances across both seasons.Conclusions:These findings highlight the potential of recycled bedding sand as a bacterial reservoir that warrants further study.

Experimental Study of Sand Bed Configurations in Front of a Vertical Wall Under Wave Action

When a 2-D progressive wave train normally or obliquely approaches a vertical wall and then is normally or obliquely reflected from it, the combination of the approaching and reflected waves may result in a standing wave or a short-crested wave in front of the wall. This paper presents the experimental observations of sand bed configurations under the action of these water waves in front of the wall. The geometry of sand ripples under these water waves in front of the vertical wall is presented as a function of flow parameters, such as the water particle semi-excursion and the mobility number.

Large Scale Multiplication of Casuarina junghuhniana Miq. Clonal Plants through Mini-cutting Technique

The modern concept of meeting the customer’s requirements in better products at low costs in a sustainable manner is possible only through innovative methods.The nodal cutting technique is the most widely used method for large scale propagation of Casuarina,Eucalyptus and other pulpwood species in India.Tamil Nadu Newsprint and Papers Limited(TNPL)has started large scale multiplication of Casuarina junghuhniana Miq.using mini-cutting technique from indoor clonal mini hedges raised in sand beds.When compared to stem/nodal cuttings,indoor clonal mini hedges raised in sand beds improve the rooting potential,quality of root systems and are time-and cost-saving.The productivity of cuttings is increased five times in indoor clonal hedge orchard than conventional stem/nodal cutting.The rooting percentage also improved to 90%without rooting hormone whereas the same is only 50%in stem cutting.The plant developed through mini-cutting technique has more lateral root system which helps the plants/trees to withstand during heavy winds.Replacing such stump derived stock plants by intensively managing indoor sand bed clonal mini hedges resulted in a noticeable enhancement of cutting capacity for adventitious rooting as well as the overall quality of the plants produced in much shorter period with easier and cheaper maintenance.The study reveals that mini-cutting method is ideal propagation technique for large scale propagation of C.junghuhniana clones in India.

Three-Dimensional Morphodynamic Modelling of Tigris River in Baghdad

Bathymetric and land surveys were conducted for the northern Tigris River reach （18 km length） in Baghdad, producing 180 cross sections. A river bed topography map was constructed from these cross sections. The velocity profiles and the water discharges were measured using ADCP （Acoustic Doppler Current Profiler） at 16 cross sections, where intensive number of sediment samples was collected to determine riverbed characteristics and sediment transport rate. The three-dimensional morphodynamic model （SSIIM （simulation of sediment movements in water intakes with multiblock option）） was used to simulate the velocity field and the water surface profile along the river reach. The model was calibrated for the water levels, the velocity profiles and the sediment concentration profiles using different combinations of parameters and algorithms. The calibration and the validation results showed good agreement with field measurements, and the model was used to predict the future changes in river hydro-morphology for a period of 14 months. The results of the future predictions showed the Tigris River which behaved like an under-fit river, increases in depositions on the shallow part of the cross section having lower velocity, and the river deepens the incised route to fit its current hydrologic condition leaving the former wide section as a floodplain for the newer river. The net deposition/erosion rate was 67.44 kg/s in average and the total deposition quantity was 2.12 million ton annually. An expansion in the size of current islands was predicted. An indication of the potential threats of the river banks＇ collapse and the bridge piers＇ instability was given by high erosion along the thalweg line.

Synthesis and Evaluation of a Water-Swelling Polymer Plugging Agent SWL-1

In this paper, to solve the problems of low water absorption and weak pressure bearing capacity of current plugging materials, acrylic acid (AA), acrylamide (AM), and sodium allyl sulfonate (SAS) are used as monomers, and soluble starch is used as grafting. Material, the use of free radical aqueous solution method to synthesize the plugging agent SWL-1 with good water absorption and strong salt resistance. The monomer ratio is set as n (AA):n (AM):n (SAS) = 5:2:1, the experimental synthesis temperature is 70°C, and the orthogonal experiment is used to determine the experimental synthesis conditions as AA neutralization degree 80%, The amount of initiator is 0.60%, the amount of crosslinking agent is 0.50%, the ratio of monomer to starch is 7:1, and the amount of calcium carbonate is 13%. The comprehensive evaluation of the performance of the plugging agent SWL-1 shows that the water absorption performance at 60°C is the best 268.78 g/g, and the water absorption performance in 8% NaCl, 0.9% CaCl2 and composite brine is 21.5 g/g, 12.5 g/g and 24.9 g/g, indicating good resistance to sodium and calcium, the water retention rate is still higher than 30% after 15 days at 160°C. The sand bed plugging test found that the maximum pressure of SWL-1 was 7 MPa, and the crack plugging test found that when the crack width was 1 mm, 2 mm, and 3 mm, the maximum compressive strength of SWL-1 was 10 MPa. The acid solubility test showed that the maximum pressure was 10 MPa. The highest rate is 86.38%.

SIZE DISTRIBUTIONS OF COARSE SAND BED LOAD IN TURBULENT FLOW FIELD

Putting forth effort on analyzing the action of turbulent flow on the sand particles on rvier bed surface,in this paper, the interdependent relation between the size distribution of coarse sand bed load and flow strength is studied.A theoretical calculation formula obtained gives good results in accordance with the field data.

Sand storms:CFD analysis of Reynolds stress and collision stress of particles near sand bed

Sand storm is a serious environmental threat to humans. Sand particles are transported by saltation and suspension, causing soil erosion in one place and deposition in another. In order to prevent and predict sand storms, the causes and the manners of particle motions must he studied in detail. In this paper a standard k-8 model is used for the gas phase simulation and the discrete element method （DEM） is used to predict the movements of particles using an in-house procedure. The data are summarized in an Eulerian-Eulerian regime after simulation to get the statistical particle Reynolds stress and particle collision stress. The results show that for the current case the Reynolds stress and the air shear stress predominate in the region 20-250 mm above the initial sand bed surface. However, in the region below 3 ram, the collision stress must be taken into account in predicting particle movement.

A novel application of fluidization-Integrating three processes in reclaiming foundry sand

Immersion of automotive parts in a fluidized bed of foundry sand is used to both strip the castings free from moulding sand and to heat-treat the castings at 500℃. The fluid bed is heated by hot gases from a burner directed first into a serpentine heat exchanger located near one side-wall of the rectangular tank, and then into a distributor consisting of horizontal sparger pipes having maintenance standpipes fixed into their upper surfaces.

Water softening by induced crystallization in fluidized bed

Fluidized bed and induced crystallization technology were combined to design a new type of induced crystallization fluidized bed reactor. The added particulate matter served as crystal nucleus to induce crystallization so that the insoluble material, which was in a saturated state, could precipitate on its surface. In this study, by filling the fluidized bed with quartz sand and by adjusting water pH, precipitation of calcium carbonate was induced on the surface of quartz sand, and the removal of water hardness was achieved. With a reactor influent flow of 60 L/hr, a fixed-bed height of 0.5 m, pH value of 9.5, quartz sand nuclear diameter of 0.2-0.4 mm, and a reflux ratio of 60%, the effluent concentration of calcium hardness was reduced to 60 mg/L and 86.6% removal efficiency was achieved. The resulting effluent reached the quality standard set for circulating cooling water. Majority of the material on the surface of quartz sand was calculated to be calcium carbonate based on energy spectrum analysis and moisture content was around 15.994%. With the low moisture content, dewatering treatment is no longer required and this results to cost savings on total water treatment process.