In this paper, dynamic MOE and static MOE of short-length radiata pine specimens produced for finger jointing were measured using non-destructive technique and correlated to each other. In order to obtain reliable static MOE data, 36 mm thickness shooks as well as the matched samples of reduced thickness (15mm) were tested, and the effect of annual growth rings on dynamic and static MOE is also addressed. Mathematical correlations were fitted between the dynamic MOE for the 36 mm thick shooks and the static MOE of the 15 mm thick samples. The coefficient of determination for dynamic MOE group 4,00-7,99 GPa was the strongest (R 2 = 0,82) and the correlation strength was further improved for sorted quarter sawn samples (R 2 = 0,92). Finally, the correlation between static modulus of rupture (MOR) and dynamic MOE is discussed.
The sound insulation and directivity of the radiated sound from double glazed windows have been measured by different researchers. Previously, airborne sound insulation models have been used to predict the associated measurement results with limited success. In this paper, the importance of accounting for the structure borne sound transmission between two glazing elements via the window frame on the prediction results is demonstrated. The decreased stiffness of the wall cavity as the depth is increased is the reason why sound transmission via the window frame needs to be considered. The reciprocity argument provided by Davy for the prediction of the directivity of sound radiating into a room is validated and it is shown that once the structure borne transmission is considered, an additional weighting term is not needed to compensate for the extra wall collisions which the sound experiences when radiated at grazing incidence.
Numerous experimental investigations have been conducted into the sound transmission loss of double leaf wall systems. From these investigations, it has been observed that the properties of the wall panels, material placed within the wall cavity as well as the type of wall connections used, greatly influence the sound transmission through the wall system. In all of these cases the wall cavity greatly affects the extent of this influence and in some cases it can even nullify their effect when changes are made. In this paper the influence of the wall cavity based on experimental trends is investigated. The investigation revealed that a wide variety of conclusions were obtained by different researchers concerning the role of the cavity and the properties of any associated sound absorption material on the sound transmission loss through double leaf wall systems. Consequently recommendations about the ways in which sound transmission through cavity systems can be improved should always be qualified with regard to the specific frequency range of interest, type of sound absorption material, wall panel and stud characteristics.
Virus transmission studies were conducted under glasshouse conditions using the vector Bemisia tabaci biotype B to determine how effectively isolates of the begomoviruses Tomato yellow leaf curl virus (TYLCV) and Tomato leaf curl Bangalore virus (ToLCBV) could be transmitted to phaseolus bean, capsicum and tomato test plants, the latter host used as a positive control for transmission. Diagnostic detection of viruses in these host crops and vector was also evaluated. Polymerase chain reaction (PCR) detection of TYLCV in bean cv. Wade and capsicum cv. Bellboy was achieved 4 weeks after fumigation in asymptomatic plants. Detection of TYLCV in tomato controls was achieved 2 weeks after fumigation with improved frequency of detection at 4 weeks. PCR was found to be a more sensitive method than triple-antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA) for the detection of TYLCV isolates in all hosts. ToLCBV was detected by PCR and TAS-ELISA in bean. TYLCV was also detected by PCR in the vector, with a novel internal positive control. This work was carried out to facilitate the development of a diagnostic protocol for the begomoviruses causing tomato yellow leaf curl under the EU SMT programme project -'Diagnostic protocols for organisms harmful to plants' (DIAGPRO).
Theories used to predict the sound insulation of double-leaf cavity wall systems are usually based on the assumption that the wall is of an infinite extent. To account for the effect of the finite extent of the wall, limiting the angle of incidence, a finite radiation efficiency model or the spatial windowing method is used in order to obtain realistic predictions. However, the effects of the finite extent of the cavity are often not included. This paper presents an extension of a finite two-dimensional cavity theory to include limp panels on each side of the cavity. It is shown that the oblique incidence mass-air-mass resonance can only occur for certain frequencies and certain angles of incidence. This is the reason why the infinite extent theories under-predict the sound insulation. The results of the predicted sound insulation agree with measurements when the wall cavity is empty. To obtain agreement when the cavity is full of a porous sound absorbing material, a flow resistivity of about one-fifth of the measured value has to be used. Use of the actual flow resistivity gives sound insulation values that are 10 dB too high.
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