Predict Shear Force Research Articles

Preslaughter stress and beef quality in relation to slaughter transport of cattle

Preslaughter handling inevitably exposes cattle to stress, which affects beef quality and yields. Short transports to the slaughterhouse or a short walk across the yard to a mobile abattoir parked on the farm may reduce stress, with potential beneficial effects on meat quality. To compare different road transport distances to a stationary (fixed) slaughterhouse, and the stationary plant with a mobile abattoir, we studied commercial slaughter of 298 cattle in each facility over a period of 13 months. For the stationary slaughterhouse, the estimated transport distance from farm to plant was 7–250 km (mean 99 km) and 96 animals spent one night in lairage there. All animals at both slaughterhouses were stunned with a captive bolt gun. Blood levels of cortisol, glucose and lactate at exsanguination and meat quality indicators were recorded. According to two-sample t-tests, thawing loss was 1 percent unit lower (p<0.0001), Warner-Bratzler shear force was 6.9 N lower (p<0.0001) and compressive load was 3.9 MPa lower (p<0.0001), but mean lactate level was 1.02 mmol/l higher (p<0.0001) and ultimate pH was 0.05 units higher (p=0.0001) in the mobile facility compared with the stationary. Effects of slaughter facility and estimated road transport distance to the stationary plant on blood lactate, ultimate meat pH, shear force and compressive load were analysed by generalized linear mixed models, with delivering farm as random effect. According to the models, predicted shear force was 23% higher at the 95th percentile of the transport distance compared with the 5th percentile (p=0.012), and there was some evidence of a similar difference in compressive load for heifers, albeit only marginally significant (39% higher at the 95th percentile; p=0.056). Predicted blood lactate was 19% higher in the mobile abattoir than the stationary slaughterhouse (p=0.046). Ultimate meat pH was higher in the mobile unit for cows and steers (p≤0.0020), and for carcasses weighing 311–380 kg (p≤0.0020). Compressive load was 27% lower in the mobile abattoir, compared to the stationary (p<0.0001), but shear force did not differ significantly between the two facilities. This study shows a negative effect of long transport distances on beef tenderness. It also provides evidence of differences in beef quality between a mobile abattoir and a stationary slaughterhouse, although these differences may be attributable to specific routines for carcass handling and ageing at the studied facilities, and not the transport and slaughter strategy itself.

A Proteomic Study for the Discovery of Beef Tenderness Biomarkers and Prediction of Warner-Bratzler Shear Force Measured on Longissimus thoracis Muscles of Young Limousin-Sired Bulls.

Beef tenderness is of central importance in determining consumers’ overall liking. To better understand the underlying mechanisms of tenderness and be able to predict it, this study aimed to apply a proteomics approach on the Longissimus thoracis (LT) muscle of young Limousin-sired bulls to identify candidate protein biomarkers. A total of 34 proteins showed differential abundance between the tender and tough groups. These proteins belong to biological pathways related to muscle structure, energy metabolism, heat shock proteins, response to oxidative stress, and apoptosis. Twenty-three putative protein biomarkers or their isoforms had previously been identified as beef tenderness biomarkers, while eleven were novel. Using regression analysis to predict shear force values, MYOZ3 (Myozenin 3), BIN1 (Bridging Integrator-1), and OGN (Mimecan) were the major proteins retained in the regression model, together explaining 79% of the variability. The results of this study confirmed the existing knowledge but also offered new insights enriching the previous biomarkers of tenderness proposed for Longissimus muscle.

Influence of antibiotic pellets on pore size and shear stress resistance of impacted native and thermodisinfected cancellous bone: An in vitro femoral impaction bone grafting model

IntroductionMorphology and mechanic properties of impacted cancellous bone are affected by carrier substances which provide high local concentrations of antibiotics. MethodsBone chips were taken from the femoral head of 6–7 months old piglets. One half was thermodisinfected and the other remained native. Ten specimens each were mixed with Herafill® antibiotic pellets and a control group of each 10 specimens respectively was examined. The cancellous bone was impacted according to Exeter technique and the implants were cemented. The distribution of the particles and the pores were defined with three dimensional computertomographic scan and shear force resistance was measured until failure. ResultsShear force resistance was not measured significantly less for thermodisinfected (2.7 Nm) compared with native bone (3.5 Nm) and addition of antibiotic pellets reduced shear force resistance in both groups since this was significant for the native group. The average pore volume of the native bone specimens appeared significant smaller compared to the thermodisinfected group (p = 0.011) and the pore volume showed a negative correlation with shear force resistance (p = 0.044). Pore volume around the pellets was found significantly increased and it appeared smaller for native bone. The number of pellets located next to the implant showed a negative correlation with shear force resistance (p = 0.034) and the negative correlation increased for pellets below the tip of the shaft model (p = 0.024). ConclusionAdding antibiotic pellets to native and thermodisinfected impacted cancellous bone increased pore volume since the area around the pellets showed increased porosity which correlated with reduced shear force resistance. Computertomographic three dimensional measurement of porosity might predict shear force resistance of impacted cancellous bone and improve impaction of bone grafting intraoperatively.

Prediction of meat quality traits in Nelore cattle by near-infrared reflectance spectroscopy.

The main definition for meat quality should include factors that affect consumer appreciation of the product. Physical laboratory analyses are necessary to identify factors that affect meat quality and specific equipment is used for this purpose, which is expensive and destructive, and the analyses are usually time consuming. An alternative method to performing several beef analyses is near-infrared reflectance spectroscopy (NIRS), which permits to reduce costs and to obtain faster, simpler, and nondestructive measurements. The objective of this study was to evaluate the feasibility of NIRS to predict shear force [Warner-Bratzler shear force (WBSF)], marbling, and color (*a = redness; b* = yellowness; and L* = lightness) in meat samples of uncastrated male Nelore cattle, that were approximately 2-yr-old. Samples of longissimus thoracis (n = 644) were collected and spectra were obtained prior to meat quality analysis. Multivariate calibration was performed by partial least squares regression. Several preprocessing techniques were evaluated alone and in combination: raw data, reduction of spectral range, multiplicative scatter correction, and 1st derivative. Accuracies of the calibration models were evaluated using the root mean square error of calibration (RMSEC), root mean square error of prediction (RMSEP), coefficient of determination in the calibration (R2C), and prediction (R2P) groups. Among the different preprocessing techniques, the reduction of spectral range provided the best prediction accuracy for all traits. The NIRS showed a better performance to predict WBSF (RMSEP = 1.42 kg, R2P = 0.40) and b* color (RMSEP = 1.21, R2P = 0.44), while its ability to accurately predict L* (RMSEP = 1.98, R2P = 0.16) and a* (RMSEP = 1.42, R2P = 0.17) was limited. NIRS was unsuitable to predict subjective meat quality traits such as marbling in Nelore cattle.

A simplified model of plain weave fabric reinforcements for the pure shear loading

An analytical and non-linear finite element (FE) modelling approach of plain weave fabric reinforcements have been developed to predict shear force for pure shear condition. For simplicity two main components of force for shear deformation has been considered; one is force required for the elastic deformation and another is to overcome the frictional resistance. Coulomb friction model of ANSYS is used in the FE model whereas the boundary condition has been established using Lagrangian description. Modelling of frictional resistance due to contact between yarns and crossover are conducted by utilizing contact pair option in ANSYS. A good agreement between theoretical and FEA model have been obtained. To ensure pure shear deformation in the fabrics it has been proved that there are no stress (von Mises and normal) or tension exist in the deformed yarn.

Prediction of intramuscular fat content using CT scanning of packaged lamb cuts and relationships with meat eating quality

Novel, multi-object X-ray computed tomography (CT) methodologies can individually analyse vacuum-packed meat samples scanned in batches of three or more, saving money and time compared to scanning live animals. If intramuscular fat (IMF), as a proxy for meat quality, can be predicted with similar accuracies as in live lambs, this method could be used to grade on quality, or to inform breeding programmes. Lamb loin cuts from commercial carcasses (n=303), varying in fat and conformation grade, were vacuum-packed and CT scanned, then tested for meat quality traits and by a trained taste panel. Tissue density values measured by CT, alongside carcass and loin weights, predicted IMF with moderate accuracy (R2 0.36), but did not accurately predict shear force or sensory traits. Juiciness and flavour increased linearly with IMF, whilst texture and overall liking increased to an optimum between 4 and 5% IMF. Samples predicted by CT as having >3% IMF scored significantly higher for sensory traits, than those predicted as <3% IMF.

Nonlinear finite element modelling and parametric study of CFRP shear-strengthened prestressed concrete girders

This paper presents a three-dimensional nonlinear finite element (FE) model for prestressed concrete girders strengthened in shear with externally bonded carbon fibre reinforced polymer (CFRP) reinforcement. A total strain rotating crack model, where the crack direction changes with the change in the direction of the principal tensile stress, was used for the concrete. In this model, explicit modelling of the concrete shear behaviour after cracking, e.g. via a shear retention parameter, is not required as the crack plane is always a principal plane with no shear stresses. The FE model was validated using experimental results from the literature. An extensive parametric study was carried out to identify the effect of the concrete compressive strength, CFRP width-to-spacing ratio, CFRP thickness, girder effective depth, shear span to effective depth ratio, level of prestress, tendon profile, pre-cracking and CFRP-to-concrete interface model on the predicted shear force capacity. The results suggested that the predicted shear strength enhancement can be significant and increases with the increase in concrete compressive strength, CFRP width-to-spacing ratio, and CFRP thickness but decreases with the increase in girder effective depth and shear span to effective depth ratio.

Raman spectroscopy compared against traditional predictors of shear force in lamb m. longissimus lumborum

A Raman spectroscopic hand held device was used to predict shear force (SF) of 80 fresh lamb m. longissimus lumborum (LL) at 1 and 5days post mortem (PM). Traditional predictors of SF including sarcomere length (SL), particle size (PS), cooking loss (CL), percentage myofibrillar breaks and pH were also measured. SF values were regressed against Raman spectra using partial least squares regression and against the traditional predictors using linear regression. The best prediction of shear force values used spectra at 1day PM to predict shear force at 1day which gave a root mean square error of prediction (RMSEP) of 13.6 (Null=14.0) and the R2 between observed and cross validated predicted values was 0.06 (R2cv). Overall, for fresh LL, the predictability SF, by either the Raman hand held probe or traditional predictors was low.

Predicting tenderness of fresh ovine semimembranosus using Raman spectroscopy

A hand held Raman probe was used to predict shear force (SF) of fresh lamb m. semimembranosus (topside). Eighty muscles were measured at 1 day PM and after a further 4 days ageing (5 days PM). At 1 day PM sarcomere length (SL) and particle size (PS) were measured and at 5 days PM, SF, PS, cooking loss (CL) and pH were also measured. SF values were regressed against Raman spectra using partial least squares regression and against traditional predictors (e.g. SL) using linear regression. The best prediction of SF used spectra at 1 day PM which gave a root mean square error of prediction (RMSEP) of 11.5 N (Null = 13.2) and the squared correlation between observed and cross validated predicted values (R2cv) was 0.27. Prediction of SF based on the traditional predictors had smaller R2 values than using Raman spectra justifying further study on Raman spectroscopy.

Finite element modelling of fabric shear

In this study, a finite element model to predict shear force versus shear angle for woven fabrics is developed. The model is based on the TexGen geometric modelling schema, developed at the University of Nottingham and orthotropic constitutive models for yarn behaviour, coupled with a unified displacement-difference periodic boundary condition. A major distinction from prior modelling of fabric shear is that the details of picture frame kinematics are included in the model, which allows the mechanisms of fabric shear to be represented more accurately. Meso- and micro-mechanisms of deformation are modelled to determine their contributions to energy dissipation during shear. The model is evaluated using results obtained for a glass fibre plain woven fabric, and the importance of boundary conditions in the analysis of deformation mechanisms is highlighted. The simulation results show that the simple rotation boundary condition is adequate for predicting shear force at large deformations, with most of the energy being dissipated at higher shear angles due to yarn compaction. For small deformations, a detailed kinematic analysis is needed, enabling the yarn shear and rotation deformation mechanisms to be modelled accurately.

A constituent-based predictive approach to modelling the rheology of viscous textile composites

In this study, a constitutive model to predict shear force versus shear angle for a viscous textile composite sheet is developed, based on fibre volume fraction, textile architecture and matrix rheology. The model is evaluated using results obtained for a pre-consolidated 2×2 twill weave glass/polypropylene thermoplastic textile composite and a 5-harness satin weave carbon/epoxy thermoset prepreg. The model is based on an adaptation of uniaxial continuum theory for continuous fibre-reinforced composites. Meso- and micro-kinematics of deformation are considered in determining contributions to energy dissipation during shear. Contributions from a number of sources are included, representing shearing of the matrix between and within tows and also at tow crossovers. The model can represent the effects on shear resistance due to forming conditions (temperature and rate) through incorporation of the matrix rheology. As this is fundamentally a predictive modelling approach, it should facilitate the improved design of materials and optimisation of component manufacture.