<span style="font-size:10.0pt;font-family:;" "="">The objective of this study was to examine the effect of compost, rice straw and sawdust amendment on hydraulic and pore characteristics of a clay loam soil. Amendments were applied at an application rate of0.2 m³/m³ (apparent soil volume) in three rectangular plots each comprising an area of3.0 m². Water retention characteristics were measured by hanging water column and centrifuge method. Hydraulic conductivity was measured by disc permeameter at -15.0, -6.0, -3.0 and0 cmof water pressure heads. Volumetric water content increased in all amended soils, compared with the control. Unsaturated hydraulic conductivity was almost identical for straw and sawdust at all pressure heads, although that for compost amended soils were much higher. Field saturated hydraulic conductivity (<i>K_fs</i>) was higher in organic matter amended soils as were number of macropores (14.7%</span><span style="font-size:10.0pt;font-family:;" "=""> </span><span style="font-size:10.0pt;font-family:;" "="">-</span><span style="font-size:10.0pt;font-family:;" "=""> </span><span style="font-size:10.0pt;font-family:;" "="">29.2%). Contribution of each pore class to the total saturated flux was evaluated from the hydraulic conductivity and water retention measurement. A new alternative weighed factor (<i>W_e</i>) was proposed to estimate the actual contribution of macro- and mesopores to the total saturated water flux. The <i>W_g</i> was found to be more representative for calculating pores contribution to saturated water flux than that of hydraulic conductivity measurement. Although there is only a small fraction of the total porosity, amendment increased effective macro- and meso</span><span style="font-size:10.0pt;font-family:;" "="">-</span><span style="font-size:10.0pt;font-family:;" "="">porosity (</span><i><span style="font-size:10.0pt;font-family:Symbol;"><span>q</span></span>_{<span style="font-size:10.0pt;font-family:Symbol;"><span>e</span></span>}</i><span style="font-size:10.0pt;font-family:;" "="">). Pores in the amended soils were hydraulically active and water movement was dominated by gravity. Collectively, our results demonstrated that organic matter generated as agricultural by-product could effectively be used to improve soil quality</span>

The apparent viscosity of 17 commercially available alginate impression materials was examined using a rheometer. Each material was mixed for 15 s at a temperature of 23 +/- 0.5 degrees C, using a specially designed alginate mixing instrument. The water powder ratio was determined according to the manufacturer's instruction. The mixed alginate paste was immediately transferred to the sample stage of the rheometer or to a commercial perforated metal tray. Over the same time scale adjusted according to the rheometer test, a discrimination test (subjective test) was performed by 16 young dentists (each with more than 4 years experience). The apparent viscosity of all materials rose as a function of time after mixing and most of the material had properties similar to pseudoplastic fluids. The relationship between the results of the subjective test and the experimental values (objective test) with the rheometer was expressed in a quadratic equation. The maximum value of the apparent viscosity derived from this result was 1.52 x 10(3) Pa.s.

The apparent viscosity of alginate impression paste prepared by three mixing methods (hand-mixing technique (HM), semiautomatic instrument (SM) and automatic mixing instrument (AM)), and the gel strength and surface depression of the respective set materials were measured. The materials used were eight commercially available products mixed at a temperature of 23 +/- 0.5 degrees C and allowed to set. The AM had a high mixing speed, which reduced the working time 4.4-31.5%, compared with HM. This was the result of an increase in paste temperature during mixing. In the case of impression materials mixed with the AM, the gel strength and the surface depression at the gel fracture increased significantly, in accordance with Fisher's protected least significant difference (PLSD) analysis. This phenomenon is caused by a decrease of air bubbles in the set material.

Information on the decomposition and nutrient release pattern of fresh and composted residues under low temperature field conditions is still limited. A 540-day period litterbag study was conducted in an agricultural field of the northeastern Japan to quantify mass loss and C and N release from fresh (rice straw and sawdust) and composted (compost) residues. Decomposition rates (k) were estimated from mass loss data by fitting a single-pool exponential decay model for actual days of field incubation. The k values were also expressed in degree-days (DGD) and decomposition-days (DCD) time scales to account for the effect of temperature and precipitation on residue decomposition. At any time scales, k values followed the order: compost > straw > sawdust. Daily mass loss, C and N release were significantly affected by residue type and incubation time. Compost showed higher decomposability and potential N source, while a considerable amount of N was immobilized in straw and sawdust decomposition. Mass loss was positively correlated with initial C content and C: N for compost and straw, while it was negatively correlated with initial N content for straw and sawdust. Decomposition exhibited at a slow rate even at sub–zero air temperature during soil freezing conditions, indicating that residue decomposition under cold climate field conditions may be more regulated by moisture availability than temperature per se

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