Evaluation of glue line shear strength of laminated timber structures using block and core type specimens

Monitoring and evaluation of glued laminated timber structures in service is essential to warrant its integrity, where non-destructive techniques play an important role. This paper describes the results obtained on glued laminated timber beams of maritime pine, with and without preservative treatment, and of spruce, exposed to natural outdoor environment as well as to artificial weathering. The assessment of glue lines’ shear strength was investigated through the extraction and testing of cores parallel and perpendicular to the glued lines and block shear specimens with 50 mm?×?50 mm and 20 mm?×?20 mm shear area. The results highlight the different performances of the various types of specimens tested, showing that the measured shear strength depends on the specimen size and that the size effect depends on the material strength giving a decreasing modification factor with the increase of strength in opposition to the constant factor suggested by standard EN 14080. They also show that shear testing of cores drilled perpendicular to the glued joints may be a promising tool in the assessment of glulam structures on site.     

Effects of interconnections between timber floor elements: dynamic and static evaluations of structural scale tests

European Journal of Wood and Wood Products - Long-span timber floor elements increase the flexibility of a building and exhibit a significant market potential. Timber floor elements are...     

Structural bonding of ash (Fraxinus excelsior L.): resistance to delamination and performance in shearing tests

The utilization of ash (Fraxinus excelsior L.) allows for a significant enhancement of the load-bearing capacity in structural laminated products. However, such applications fundamentally require high-strength and durable bonds between lamellas and in finger joints. Therefore, the aim of the present survey was to evaluate ash bondings in terms of resistance to delamination (EN 302-2) and shear performance (EN 392). Investigations were performed with five adhesives: phenol-resorcinol-formaldehyde (PRF), melamine-urea-formaldehyde (MUF-1, MUF-2), polyurethane (PUR), emulsion polymer isocyanate (EPI) and varying closed assembly times as key bonding parameter. For all tested adhesives and closed assembly times, the shear test showed high wood failure percentages and bond strength values that compare to solid ash. In contrast, for resistance to delamination, significant differences were found between the adhesives as well as between closed assembly times, with improving resistance to delamination for increasing closed assembly times. The best performance was determined for the PRF-adhesive and long closed assembly times. However, standard requirements for resistance to delamination could not be met by any of the adhesives. The resistance to delamination showed no correlation with the shear performance for any of the adhesives. Microscopic examination of the bonded joints revealed that both the penetration behavior of the adhesives and glueline thicknesses clearly correlated with the closed assembly time.     

Hedonic mediation of the crossmodal correspondence between taste and shape

Crossmodal correspondences between gustatory (taste), olfactory (smell), and flavour stimuli on the one hand and visual attributes on the other have been extensively documented in recent years. For instance, people have been shown to consistently match specific tastes and flavours to particular visual shapes. That said, further research is still needed in order to clarify how and why such correspondences exist. Here, we report a series of four experiments designed to assess what drives people’s matching of visual roundness/angularity to both ‘basic’ taste names and actual tastants. In Experiment 1, crossmodal correspondences between taste names and abstract shapes were assessed. Next, the results were replicated in a larger online study (Experiment 2). Experiment 3 assessed the role of liking in the association between taste words and morphed shapes along the roundness/angularity dimension. In Experiment 4, basic tastants were mapped to the roundness/angularity dimension, while the mediating role of liking for each taste was assessed. Across the 4 experiments, participants consistently matched sweetness to roundness. What is more, people’s liking for a taste (but not their liking for imagined tastes) appeared to influence their shape matching responses. These results are discussed in terms of crossmodal correspondences, and a potential role for hedonics is outlined.     

魔芋胶不同添加量与猪皮胶交互作用的研究

以魔芋胶与猪皮胶为实验原料,采用低场核磁共振(NMR)、质构仪和扫描电子显微镜(SEM)等分析魔芋胶不同添加量分别对猪皮胶内水分分布与迁移、凝胶强度和微观结构的变化探究其交互作用。实验结果表明:当魔芋胶添加量为0.5%~0.7%时,使猪皮胶内的水分分布的横向驰豫峰向左移动,一部分自由水向结合水转化,三种水分的分布情况与新鲜肉制品相似,具有良好的质感,组织状态紧密,质构仪测的凝胶强度最大,即两者此时的交互作用最强,通过扫描电镜观察猪皮胶表面的微观结构中的孔状结构也随着魔芋胶的添加逐渐变小,在添加量为0.5%时魔芋胶对猪皮胶表面的孔达到完整的填充。      

Sweet and bitter near-threshold solutions activate cross-modal correspondence between taste and shapes of cups

Recent studies have pointed out some cross-modal correspondences between flavoured beverages, as well as basic taste solutions, and specific geometric visual cues. Some of them associate known drink tastes to shapes of receptacles. In particular, sweetness is associated with curved receptacles and bitterness with sharp-angled ones. Our study aimed to test the hypothesis according to which near-threshold solutions might also activate this cross-modal correspondence. We used two different cup forms, one curved and the other sharp-angled, with pure sweet and bitter solutions just above sensorial thresholds. We designed two tasks using a two-alternative forced-choice test. Participants had to decide which drink was sweeter, Task 1, and bitterer, Task 2, from the curved and sharp-angled cups. Results showed the cross-modal correspondence but only when participants drank first from the curved cup and second from the sharp-angled cup. The effect disappeared when participants drank first from the sharp-angled cup and second from the curved cup. This suggests that the correspondence emerges using sweet and bitter near-threshold solutions in specific conditions. On the other hand, results also showed that confidence level of responses was significantly higher in the bitter task than in the sweet task. We discuss these complex results in the light of different theoretical proposals to explain this cross-modal correspondence.     

A comparison between tensile and shear adhesive strength of meat-myosin junctions

A model meat-myosin gel junction was used to compare the adhesive strength of binding junctions when subject to tensile or shear forces. This comparison was made on junctions cooked to 80°C with three different alignments of muscle fibres with respect to the junction plane. Tensile adhesive strength (TAS) and shear adhesive strength (SAS) did not differ significantly when fibres in both of the bound pieces of meat were perpendicular to the plane of the myosin gel function (90°/90° junction). However, SAS was higher than TAS if the muscle fibres in one or both of the meat pieces were parallel to the plane of the junction. This suggests that tensile failure of binding junctions is the more likely mode of failure. Differences between SAS and TAS in any one junction orientation were small compared to the effect of muscle fibre orientation with respect to the junction; both TAS and SAS were highest for 90°/90° junctions and lowest when muscle fibres in both meat pieces were parallel to the junction (0°/0° junctions).     

Multiple correspondence analysis and random amplified polymorphic DNA molecular typing to assess the sources of Staphylococcus aureus contamination in alheira production lines

Sources and tracing of Staphylococcus aureus in alheira (garlic sausage) production were evaluated by multifactorial correspondence analysis (MCA) of occurrence data and a random amplified polymorphic DNA (RAPD) on S. aureus isolates. Samples from four production lines, four different production batches, and 14 different sampling sites (including raw material, different contact surfaces, and several stages of alheira manufacturing) were analyzed at four sampling times. From the 896 microbial analyses completed, a collection of 170 S. aureus isolates was obtained. Although analysis of the occurrence data alone was not elucidative enough, MCA and RAPD-PCR were able to assess the sources of contamination and to trace the spread of this microorganism along the production lines. MCA results indicated that the presence of S. aureus in alheira was related to its presence in the intermediate manufacturing stages after heat treatment but before stuffing in the casings. It was also possible to associate a cross-contamination path related to handler procedures. RAPD-PCR typing in accordance to MCA results confirmed the cross-contamination path between the raw material and casings and the role of handlers as an important cross-contamination vehicle.     

Interrelationship between measures of collagen,compression, shear force and tenderness

This study examined the relationship between collagen content as determined by hydroxyproline assay with other measures of connective tissue, shear force and tenderness in lamb muscle. Samples were taken from both m. longissimus lumborum (LL, loin) and the m. semimembranosus (SM, topside) of 99 lambs. Sensory tenderness and compression of the LL were not correlated to any measure of collagen or connective tissue, with one exception where compression was correlated (r = − 0.28; P < 0.05) to the percentage of connective tissue determined by imaging. Intramuscular fat (IMF) was linearly correlated (P < 0.05) to sensory tenderness and compression, such that a 1% increase in IMF increased the tenderness score by 2.3 ± 0.83 units and reduced compression by 0.73 ± 0.21 N. There was no correlation between SM shear force and collagen concentration. The data suggest that measurement of collagen concentration did not explain the variation in shear force and sensory tenderness observed in the meat from lambs.     

Sensory evaluation of wine through correspondence analysis: a theoretical and empirical rationale

Sensory evaluation in wine research focuses on understanding wine preference and choice within a holistic framework. This study offers a theoretical and empirical rationale for the sensory evaluation of wine. A precondition for sustainability and success in the market arena is a clear understanding of potential interaction of sensory evaluation properties and other factors affecting consumer choice. New approaches and methodologies for preference matching and assessment of sensory properties and information queues on overall liking are of fundamental importance for wine makers. The aim of this study is to advance the understanding of sensory evaluations affecting consumer both on empirical and theoretical grounds. For the implementation of this aim, an empirical research with real wine tasting data was conducted and analyzed through the use of Correspondence Analysis (CA). The findings of this study demonstrate that this method is more appropriate in wine sensory data analysis due to their categorical and non-parametric nature. CA is a very useful technique to establish a solid knowledge for the identification of the wines based on evidence and facts of their aromatic characteristics.     

Steady and dynamic shear rheology of starches from different oat cultivars in relation to their physicochemical and structural properties

Starches isolated from eight oat cultivars were tested for their physicochemical, structural, and rheological properties. The isolated starches had low levels of ash and nitrogen contents with amylose ranging from 21.8 to 32.3 g/100 g. The amount of water released from starch gels decreased significantly (p < 0.05) with increase in freeze thaw cycle. The scanning electron micrographs revealed the presence of polygonal to irregularly shaped starch granules. All the starches exhibited A-type X-Ray diffraction pattern typically characteristic of cereal starches. The rheological properties of pastes were well described by the Herschel-Bulkley model at a shear rate of 0–100 s^?1 (R² > 0.99). The starch pastes behaved like a pseudoplastic fluid and exhibited shear thinning fluid characteristics with values of flow behaviour index considerably less than 1. Both the storage and loss moduli of the pastes increased sharply initially and then dropped after reaching the gelatinization peak. The magnitude of the dynamic rheological parameters varied significantly (p < 0.05) between the cultivars. All the starch pastes were highly elastic than viscous as evidenced by the lower tan δ values. Structure property relationships were established between starches using principal component analysis.     

Statistical properties of simple sensory difference tests: Confidence limits and significance tests

The Normal approximation to the binomial distribution is used to obtain confidence limits for the proportion of correct responses in a simple sensory difference test and the proportion of assessors able to discriminate between two products. Improved approximations, which should be considered with small panels or when the proportion of correct responses is close to 0 or 1, are discussed. To permit comparison of the discriminating ability of different panels, or investigation of the effect of a change in the products assessed, tests of the significance of the difference between two proportions are presented, based on the Normal approximation and the x² statistic. The methods are illustrated with some data from an investigation on fish flavour.     

Relationship between physicochemical and rheological properties of starches from Indian wheat lines

Starches from nine Indian wheat lines were evaluated to study the relationships between physicochemical and rheological properties. Large granules (>15 μm) were present in the highest proportion followed by medium (5–15 μm) and small granules (<5 μm). Amylose content ranged between 27.4 and 37.2%. Starch with the highest proportion of large granules (68.9%) showed higher values of G′_peak (576 Pa) and G′_final (432 Pa). Amylose content showed positive relationships with retrogradation, gel firmness, gumminess and adhesiveness while negative with springiness. Cooked starch pastes with the highest amylose content (37.2%) had higher ΔH_ret (0.88 J g^?1), G′_ret (361 Pa), adhesiveness (1.48 Ns), firmness (0.45 N) gumminess (0.22 N) and the lowest springiness (0.88). Amylose–lipid complex (AML) dissociation showed negative relations with swelling power, G′_peak, G′_breakdown and breakdown viscosity (r = ?0.779, ?0.66, ?0.771 & ?0.775, respectively, P < 0.05) while positive relationship with pasting temperature (r = 0.775, P < 0.05).     

薄型精纺毛织物悬垂性与结构参数的关系

对多种不同规格的薄型精纺毛织物的悬垂性能进行测试,采用Origin7．0软件分析了织物的悬垂性能与织物结构参数之间的关系,结果表明织物的厚度、原料、紧度和纱线的捻度对薄型精纺毛织物的悬垂性能均有不同程度的影响。     

PTT混纺织物的结构特征与服用性能

以织物结构参数(即织物紧度和织物组织)为主要研究对象,模仿派力司织物的经纬紧度比,织造36种不同紧度、不同组织的PTT混纺织物样品,采用KES-F织物风格仪研究分析了织物的服用性能,包括压缩性、弯曲性和表面性。研究结果表明:PTT混纺织物随紧度的增加,面料蓬松度下降,抵抗弯曲变形能力增强,滑爽度下降;PTT混纺织物组织的浮长线越长,织物受压缩变形、变曲变形后的回复能力越好;多种组织中,斜纹组织的表面滑爽度最好。     

毛精纺面料成形性与纬纱结构参数的关系

以三群判别法为基础,通过自制毛精纺面料样本,求取其基本力学指标、成形性判别值和指标权重等数值,得出面料成形性变化程度（矢量模）和方向（矢量方向）,探讨面料成形性动态变化趋势和纬纱结构参数的关系。通过研究得出：当纬纱细度变化量相同时,面料成形性变化矢量模相同,但其意义并不相同;在所采用的纬纱捻系数100～160范围内,一旦捻系数变化量固定不变,其对应样本之间的成形性矢量模差异不变,矢量方向变化由各力学指标权重分配综合确定。验证结果表明：得出的成形性变化矢量模、矢量方向与纬纱结构参数关系式,在一定范围内能较好地反映面料成形性与纬纱结构参数之间的变化关系,可为面料成形性设计提供理论参考。     

Effect of pelvic suspension and cooking temperature on the tenderness of electrically stimulated and aged beef, assessed with shear and compression tests

Electrically stimulated carcass sides of young bulls were suspended at 1 hr post mortem from the aitch bone (pelvic suspension; PS) and Achilles tendon (AT), respectively. After an ageing period of 14 days at 3 °C, shear force (SF) and compression (20 and 80% compression) tests of the Mm. longissimus lumborum et thoracis (LO) and semimembranosus (SM) were conducted in raw muscle and after heating for 1 hr at 55, 60, 65, 70 and 80 °C. Collagen content was higher in SM than in LO, while sarcomere length (SL) of raw muscle were 1.75 and 1.78, for LO and SM. In comparison with the AT-side, PS increased SL by 21 and 47% and cooking loss (at 80 °C) by 2 and 6% for LO and SM, respectively. Drip loss of whole muscles from the PS-side during the ageing period tended to be lower (n.s.). Over the whole cooking temperature range, SF-values were relatively high for the SM in comparison with LO. For both muscles from the AT-side, the lowest SF-values were observed at 60 and 65 °C. The PS-treatment resulted in higher SF- values for raw muscle and after cooking at low temperatures (55 and 60 °C), particularly in the SM. In the intermediate temperature range (65 and 70 °C), PS had no significant effect, while in the higher temperature range (80 °C), SF-values were lower in the PS-side. Similar tendencies were observed in the LO, although the lower SF-values for the PS-side were observed already at 60 °C. In non-destructive compression (20%), there was a gradual increase in stress values with increasing cooking temperature. In comparison with the AT-side, the PS treatment resulted in the LO in similar or higher, and in the SM in lower stress values. With destructive compression (80%), PS resulted in SM in higher stress values in raw muscle and at 55 °C, in accordance with the SF-values. It is suggested that the higher SF- and 80% compression values in raw muscle and at low cooking temperatures, are caused by an increase in collagen strength due to a change in the direction and spatial organisation of the collagen fibres as a result of stretching of the muscle. This study demonstrates that the relative contributions of the collagen and myofibrillar components to the mechanical assessed toughness, as well as the effect of pelvic suspension, is dependent of muscle, cooking temperature and the mechanical test applied.     

An objective measure of muscularity: Changes with animal growth and differences between Genetic lines of southdown sheep

A measure of muscularity, based on objective measurements, and expressed in terms of muscle depth relative to skeletal dimensions, is proposed and investigated using a simulation model. Average muscle depth is assessed as the square root of the muscle weight per unit length of a bone adjacent to the muscle. Muscularity is then defined as average muscle depth divided by bone length. Evidence based on a theoretical model, results from the literature and data from backfat selection lines of Southdown sheep is used to illustrate how muscularity defined in this way changes with growth, and the extent to which it parallels changes in muscle to bone ratio. It is concluded that although these two characteristics often change together there are situations where differences in muscularity are not accompanied by differences in muscle to bone ratio and vice versa.