An experimental study on changes in sound absorption capability of spruce (Picea sitchensis), Douglas fir (Pseudotsuga menziesii), and larch (Larix kaempferi) after microwave treatment

This study investigated changes in the sound absorption coefficients of three anatomical sections of cubed spruce (Picea sitchensis), Douglas fir (Pseudotsuga menziesii), and larch (Larix kaempferi) after microwave treatment. Microwave treatment at 1000 W and 2.4 GHz for 20 min increased the sound absorption coefficients (at 2000–5000 Hz) of spruce by 6.9% in the transverse section, 20.0% in the radial section, and 31.7% in the tangential section. The sound absorption coefficients of Douglas fir increased by 28.9% in the transverse section, 19.1% in the radial section, and 50.0% in the tangential section. Larch coefficients increased by 16.7% in the transverse section, 37.2% in the radial section, and 38.8% in the tangential section. The sound absorption coefficients of the softwoods differed according to species and anatomical plane after microwave treatment. It was concluded that changes in the measured sound absorption coefficient indicate alteration in the pore structure of wood, which can affect in turn wood permeability and impregnation. These data will be helpful for predicting the permeability and impregnation of wood after microwave treatment.

Systematic wood anatomical study in some species of Sapindaceae Juss. in South-Western Nigeria

Comparative wood anatomical studies was carried out on ten species in the family Sapindaceae. The species were relatively uniform in the features of their vessels, in which diffuse porous was observed with solitary vessels to pore multiples in transverse section and ray cells were predominantly heterogeneous in radial section. Fibres were long and extensive. The longest fibre was observed in Blighia sapida (1025±28.5 µm), while the shortest fibre was observed in Cardiospermum halicacabum (139±6.5 µm). The longest vessel was observed in Deinbolia pinnata (509±34.9 µm) and the shortest vessel was observed in Cardiospermum halicacabum (85.36±4.9 µm). The implication of these features in the taxonomy of the family was discussed. The Dendrogram based on the quantitative wood characters confirmed Allophylus africanus and Allophylus spicatus belong to the same genus as classified, likewise Blighia unijugata, Blighia sapida but Cardiospermum halicacabum is closely related to Paullinia pinnata while others exhibited distinct generic characters.

Effect of an axial-radial plate reactor modifications on a mega methanol plant production

Axial-radial flow plate reactors have been recently considered as efficient and practical types of reactors for methanol synthesis. Generally, an axial–radial reactor (AR) consists of two main parts namely the axial section and the radial section and the vast majority of the feed enters the radial section. Moreover, the structure of AR has a space above the axial part, which can add an adiabatic bed in the system. In this study, the performance of two novels AR configurations is investigated to improve the effectiveness of the axial–radial plate reactor. In the first configuration, the optimum length of the adiabatic bed is calculated and the adiabatic bed is located above the axial section inside the AR and is named IAAR. Therefore, in IAAR the feed of the axial section just enters the adiabatic bed and warms up. On the other configuration, the adiabatic bed with the optimum length is placed outside the reactor and is named OAAR. Therefore, in OAAR the total feed passes through the adiabatic bed, highly warms up, then cools to the optimum temperature in a heat exchanger, and finally enters AR. Two-dimensional mathematical modeling via orthogonal collocation on the finite element method is developed to compare the performance of two configurations. The results show that the maximum proportion of methanol produces in IAAR, which is approximately 3.8% higher than that produced in conventional AR due to utilizing an adiabatic bed inside the AR and superior gas distribution in the process. Momentum, mass, and heat equations are calculated and molar flow rates, mole fractions and temperatures are depicted along the radius and the length of the three configurations.

A Comparison of the Loading Direction for Bending Strength with Different Wood Measurement Surfaces Using Near-Infrared Spectroscopy

Wood is widely used throughout society for building resources and paper. To further expand wood’s use in the wood industry, we tested the bending strength properties of wood and certified its internal quality by using near-infrared spectroscopy (NIRS). In this study, the relationship between bending strength and loading direction was compared by changing the light acquisition point of wood surfaces to elucidate the anisotropy of the wood using NIRS. The two loading directions were defined by using a bending test as the radial section and the tangential section. Two light acquisition points with NIRS were also defined by a bending test as the loading position (the compression surface) and the opposite surface (the tensile surface), and a comparison was made between the prediction accuracy of the wood’s mechanical strength properties obtained via a bending test using two pieces of light acquisition data. The strength properties of the wood bending tests were the elastic modulus in bending (Eb), the bending strength (Fb) and density (DEN). Cryptomeria japonica was prepared and cut into a final size of 20 mm × 20 mm × 320 mm. Near-infrared (NIR) spectra were obtained from the compression force side and the tensile force side (calculating these averages), and a partial-least-squares regression (PLSR) was performed for the regression analysis. In the NIR measurement position, the best calibration results of the PLSR were the averaged data between the side undergoing the compression force and that undergoing the tensile force. Comparing the two loading directions, the result for the radial section was slightly superior to that of the tangential section. The radial section showed a good relationship between the spectra acquisition position and the arrangement of the wood’s structure. The estimation accuracy of bending strength properties differed depending on the location where the NIR spectra acquisition was performed.

Thermal condition of cohesion in a two-layer roll of a rolling mill

A condition of heat exchange between the layershaving different thermalphysic properties in a two-layercylindrical roll of a rolling mill is analyzed foe an ideal thermalcontact. It can be realized with application of the condition ofheat balance of one of the layers in the cylindrical area for ahomogeneous equation of heat conductivity. Analyzed was asimplified target setting in the radial section with a supposition,regarding an averaged in radius temperature distribution in theouter layer. By applying the condition of the thermal balance andby integrating the homogeneous equation of heat conductivity inthe two-layer area a condition of cohesion of an impedance typein case of an ideal thermal contact between the layers wasconstructed.

Experimental precision study of types and of the chemical composition of nonmetallic inclusions in radial section of the railway axis by the method of the electronic microscopy and x-ray spectral microanalysis

Purpose. Investigation of the structure and composition of non-metallic inclusions in the radial section of the draft railway axis obtained from continuously cast billets. Methodology. Studies were conducted on samples of steel EA1N using electron microscopy of X-ray spectroscopy analysis. Results. It has been established that during cooling of the melt and crystallization of the metal of a continuously cast billet, inclusions close in composition to quasi-equilibrium states of binary and ternary oxide systems are formed. Originality. The structures and composition of heterophase inclusions formed in the central part by spinel MgO * Al2O3 with the (Ca, Mn) S sulfide phase shell are identified. Practical value. The results of the study determine the modes of deoxidation and alloying of the axial metal during out-of-furnace treatment at LF and VD.