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To avoid the intrinsic difficulties regarding the characterization of wood (i.e., different applications in different directions), various normative documents present the relationships between properties; the Brazilian standard is of particular interest in this regard, because Brazil has a huge diversity of tree species from tropical forests, usually used in construction. In view of this, this research aimed to propose a new list of properties to be inserted in future versions of the Brazilian standards in order to help identify the species shear strength. It is expected that there is a correlation between the characteristic values of flexural strength (fm,k) and shear strength in the direction parallel to the wood fibers (fv,0,k), leading to models that make it possible to estimate one of the properties if the other is known, which was the main objective of this research. After finding a strong correlation between the properties, various regression models were evaluated. It can be concluded that the linear model composed only by the angular coefficient (equation with only one variable) presented a determination coefficient of 76.45%, which shows the good precision achieved in the estimation of one of the two variables compared if the other is known. Additionally, an attempt was made to define which probability distribution represents the resistance data by applying maximum likelihood (MLE), concluding that there is little difference between the representation by the normal distribution and the generalized extreme value (GEV) distribution. Another approach was to define the undermining coefficient to ensure the reliability of the prediction equation by the experiment-based calibration methodology defined by Eurocode. [ABSTRACT FROM AUTHOR]

Based on most recently published studies, there is a large variability in both the mechanical properties of wood and sample sizes selected to evaluate them. This study aims to define sampling sufficiency for some mechanical properties of wood, which were bending strength, bending modulus, compressive strength, compressive modulus, hardness, and shear strength. The mechanical tests were carried out according to an American standard procedure on wood samples cut from clonal Eucalyptus planted in southern Brazil. Sampling sufficiency was determined by an intensive computational method based on resampling of original data using Monte Carlo simulations. The experimental tests data conformed to the normal distribution and most of the obtained sufficient sample sizes determined by Monte Carlo simulation were above those sample sizes used in most already published studies. Furthermore, properties related to wood stiffness presented smaller variabilities than their respective properties associated with wood strength, leading to smaller sample sizes for the former cases. [ABSTRACT FROM AUTHOR]

The African mahogany (Khaya senegalensis) in homogenous plantations and natural forests is widely studied, but there is a lack of information on wood from trees grown in agroforestry systems (AFSs). The objective of this work was to evaluate the wood quality of African mahogany produced in AFS. The wood was obtained from a multi-stratified AFS located in the State of Rondônia, Brazil. The contents of holocellulose (67.2%) and lignin (25.8%) of mahogany wood are comparable to those found in other tropical woods from the Amazon with high natural durability. The results found for the densities presented low variation, allowing to classify the African mahogany wood as of medium density (basic density around 520 kg m−3) and high dimensional stability (ie, anisotropy coefficient <1.3%). The results obtained for parallel-to-grain compression strength (26.5 MPa), static bending strength (56.0 MPa), shear strength (10.4 MPa), and Janka hardness parallel to the grain (3420.0 N), indicate that the mechanical performance was similar to wood from other African and South American mahogany species from monocultures and natural forests. Experimental results indicated that the wood produced in the AFS can be suitable for furniture, musical instruments, applications in external structures, residential floors, and vehicle bodies. [ABSTRACT FROM AUTHOR]

Mining operations lead to the production of large quantities of mineral waste, such as fluid fine tailings whose disposal is rather challenging. In Brazil, tailings disposal is facing a critical situation due to the large accidents that took place in the last couple of years. As a response to these accidents, the Brazilian Mining Agency became stricter on licensing mining complexes and issued an interruption on activities on 56 tailings dams. In this paper, the authors propose a promising approach to minimize risks on the existing tailings dams hoping that the industry succeeds at mining avoiding social harms and environmental damages. The results presented herein showed that in situ electrical dewatering is a promising technology that offers many benefits. It can significantly increase the solids content of liquefiable tailings stratum within a short time. This leads to tailings masses possessing higher shear strength. As a consequence, this technology might well lead to safe tailing dams in Brazil bringing socio-economic and environmental benefits. [ABSTRACT FROM AUTHOR]

Clayey veins may develop in areas of hydrothermal activity by seepage of hot water through the soil and rock. In a slope located in Southern Brazil, such veins occur along the slip surface of some landslides. This paper aims to characterize this kind of clay and investigate its influence over the stability of that slope. An electro resistivity survey had been conducted to characterize the soil profile, and SPT boreholes were used to confirm geophysical data. An experimental laboratory campaign included the investigation of chemical, mineralogical, and geotechnical properties of these clay veins and the embedding residual soil. Drained shear strength of residual soil was measured through triaxial tests, and residual strength was measured for both materials using a ring shear apparatus. A series of limit equilibrium analyses were conducted to assess the role of clay veins on the slope stability. The geometrical discretization of veins is a difficult task, and an approach based on the assumption of overall shear strength is required to establish the operational shear strength parameters for this slope. A series of back analyses showed that failure surfaces consistent with those observed in the field were only reproduced when the adopted shear strength parameters of the soil mass were c' = 5 kPa and φ' = 20°. Considering the measured shear strength parameters of the hydrothermal clay c' = (0 and φ' = 8.5°) and the pattern in which the clay veins occur, it seems that they do not fully control the slope stability, but they significantly reduce the global cohesion and the average mass friction angle. [ABSTRACT FROM AUTHOR]

Erosion is a natural relief modeling process that is influenced by several factors. Among these, we highlight the soil properties, designated by the specific concept of erodibility. Most of the existing methods for quantifying erodibility are based on field plots or indirect procedures developed from farmland approaches and methodologies limited to other study conditions such as slopes, where soil structure is different. Therefore, the objective of this study is to investigate the erodibility of cutting slopes in the Quadrilátero Ferrífero region, Brazil, and its relationship with soil properties, using the hand vane test to determine undrained shear strength (SU) and associating its values with the erodibility factor K. The results show that SU has significant correlation with the fine soil particles, especially clay and silt. In addition, properties responsible for the increase in SU decrease erodibility factor K. The mean weight diameter, geometric mean diameter, and aggregate stability index parameters show that aggregate diameter and stability are associated with higher SU and, conversely, lower K values. In addition, chemical properties, especially pH, also interfere in the results, however, in lower proportion when compared with the physical indexes. Finally, the undrained shear strength has a significant negative correlation with erodibility factor K, both in non-erodible (R2 = 0.6770, p value < 0.01) and erodible (R2 = 0.7885, p value < 0.01) soils, showing promising methods in the diagnosis of potentially erodible soils. [ABSTRACT FROM AUTHOR]

Failure mechanisms of slopes along the coastal ranges of south-eastern Brazil very often indicate shallow shear surfaces, occurring at the sharp contact between the soil and the intact rock. Recent events has cost the lives of more than 800 lives due to heavy rainfalls in a very short period, in areas with and without anthropic actions. Most of the geotechnical studies are related to the shear strength of the soil in both saturated and unsaturated state. However, there is a lack of knowledge in strength parameters along soil–rock contacts. The present work attempts to fill this gap by the determination of shear strength parameters along sharp soil–rock contacts under saturated and unsaturated conditions. The present work focuses on small scale of roughness, which can be reproduced in laboratory experiments. In order to simulate these conditions, shear box tests were performed, using different interface conditions of roughness with specimens at different soil suctions. The results allowed the evaluation of the effect of roughness at the interface and soil suction on the cohesion, and friction angle, In particular, the behaviour of cohesion with variation in the degree of saturation and suction. [ABSTRACT FROM AUTHOR]

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The paper presents compression and triaxial tests conducted under controlled suction in horizons B and C of a residual soil gneissic rock profile from south-east Brazil. Horizon B, found at the surface, consists of a 2 m thick reddish lateritic clayey soil layer, whereas horizon C is a saprolitic soil layer that reaches great depths. The block samples representing horizons B and C were manually taken from depths of I m and 5 m respectively. The test programme carried out consisted of isotropic and anisotropic compression tests as well as drained and constant water content triaxial tests. Tests were performed under saturated and unsaturated conditions at controlled suction. Strength parameters c and φ were shown to increase with matric suction. The critical state parameters were shown to vary with suction, which also expanded the yield curve. Data obtained may be useful for the development of soil constitutive models for unsaturated soils. [ABSTRACT FROM AUTHOR]

The properties of municipal solid waste (MSW) in landfills vary considerably, depending on the waste's composition, time, and density. This variability in MSW properties leads to many uncertainties in the analysis of landfill performance. Therefore, this study aimed to evaluate landfilled waste's physical, chemical, and mechanical properties for 8 days. Throughout this study, it was possible to investigate the gravimetric composition, density of solid particles, moisture content, volatile solids, pH, total alkalinity, chemical oxygen demand (COD), ammoniacal nitrogen (N-NH 3 ), grain size distribution, compaction properties, and shear strength of the landfilled waste. It was found that 71% of the waste corresponds to the denominated "others" category, the content of fine materials is 65%, the optimum water content is 34%, the moisture content is 41%, and the volatile solids is 67%. The chemical parameters indicated that the MSW was in the initial phase of biodegradation (acidogenesis), as the pH, total alkalinity, COD, and N-NH 3 showed to be 5, 1575 mgCaCO3.L -1 , 13698.6 mgO2.L -1 , and 56 mgN-NH3.L -1 , respectively. On the mechanical aspect, the waste presented a cohesion of 17 kPa and an internal friction angle of 16°. In general, the results showed that the waste's physical, chemical, and mechanical properties altered during the landfilling process., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

• The role of the compaction effort on geotechnical behavior of waste foundry sands was investigated. • Increasing of compaction effort causes remarkable changes in terms of bearing capacity and shear strength. • Suction plays a remarkable role in the behavior of waste foundry sand after being air-dried. • Waste foundry sand requires a rigorous compaction control. Brazil produces more than 3 million tons of waste foundry sands (WFS) each year. Although this material presents characteristics that fulfill the environmental requirements to be recycled and used as a building material, the lack of information regarding its geotechnical behavior inhibits its use, mainly in applications that require good performance. Therefore, this study investigates the role of the compaction effort on the behavior of compacted WFS considering its application as a building material in geotechnical work. The experimental procedures include X-ray fluorescence analysis, scanning electron microscopy, determination of compaction curves, California bearing ratio (CBR), the execution of unconfined compression, direct shear, and oedometric tests. Geomechanical tests were conducted on specimens compacted with three distinct compaction efforts: 600 kJ/m3, 1260 kJ/m3 and 2700 kJ/m3. The WFS is composed mainly of quartz particles with subangular to subrounded shape. Fines are 12% of its composition, and WFS is classified as a well-graded material. Optimum moisture content ranges between 9.0 and 11.5%. The higher the compaction effort, the lower is the void ratio. Despite the differences in the void ratios are small, they affect the CBR values dramatically. Compaction effort increases friction angle and unconfined compressive strength and reduces compressibility. Suction plays a remarkable role in the behavior of such material after being air-dried. This study can contribute to a better understanding of potentialities and limitations for the use of WFS in compacted conditions. [ABSTRACT FROM AUTHOR]

Several times the use of materials with adequate mechanical properties can lead to increases in construction costs. In areas such as the Central-West region of Brazil, where the predominantly fine lateritic soils often require improvement, the investigation of mixtures between the local soil and alternative materials such as Tire Derived Aggregates (TDÁ s) is required. Despite many investigations involving soils and rubber wastes over the years, there is a lack of publication regarding lateritic soils and TDA's. This paper investigated the use of a fine lateritic soil mixed with TDÁs as an alternative composite for light traffic roads and retaining structures. Experiments were conducted in terms of materials characterization, compaction and shear strength properties, quantified using medium-scale direct shear tests. The direct shear tests were based on the compaction tests which showed that the best rubber content was 5%. The results showed that the shear strength highly depends on the level of displacement allowed, which is an important issue once the investigated soil is composed in its majority of fine particles and the occurrence of cracks can limit their use. Finally, the soil studied mixed with TDA's showed potential usage for some civil engineering constructions. [ABSTRACT FROM AUTHOR]

• Density intensely affects soil rheological parameters in weathered subtropical Oxisols. • Increasing friction increased shear resistance and reduced viscoelasticity. • Gravity-based density proved to be a useful option for special soils and studies. • Increasing frequency from 0.25 to 1.0 Hz had marginal impact on soil rheology. • Rheometry could be faster at higher frequencies without loss of data accuracy. Soil density and oscillation frequency are some of the main factors affecting soil micromechanical behavior, but their role in the oscillatory amplitude sweep test (AST) is not yet well understood. Current studies use either a reference density, i.e. field density or a density based on texture and/or organic matter content or opt for a common density for all samples, while oscillation frequency may be relevant in simulating agricultural traffic speeds and affects coupled hydraulic-mechanical processes. We analyzed the effect of soil density and AST oscillation frequency at different matric potentials of three weathered Oxisols from southern Brazil that were repacked to different densities, namely different levels of compaction, no compaction and field density. Higher density, probably due to increased cohesion and friction, increased rheological shear stress parameters: shear stresses at the end of the linear viscoelastic range (LVR), τ L ; and at the yield point (YP), τ YP ; and storage and loss moduli (G' and G", respectively) at the YP, G', G" YP. However, viscoelasticity parameters: strain at the end of LVR γ L ; strain at the YP γ YP ; and the integrated zone I z , were negatively affected at low densities with increasing magnitude at higher density levels. Uncompacted soil resulted in densities similar to field density, and delimitated a soil state where density does not interfere with friction. This suggests a methodology for the comparison of distinct soils or where information on field density is missing or unavailable. Frequency alterations from 0.25 to 1.0 Hz had low impact and only increased few rheological parameters, mainly in some soils drained at −6 kPa, but neither reduced data accuracy nor affected the samples' evaporation. Hence, rheological tests can be executed at a higher frequency than 0.5 Hz (at least up to 1.0 Hz) to increase sample output. For both density and frequency, (i) drainage increased soils micromechanical resistance due to water menisci; and (ii) soil resistance showed the order: Typic Hapludox (clayey brown-reddish Oxisol) > Rhodic Kandiudox (clayey red Oxisol) > Rhodic Hapludox (sandy red Oxisol), mainly due to the cohesive effect of clay and Fe oxides, as well as the aggregating effect of soil organic matter. [ABSTRACT FROM AUTHOR]

Forty young crossbred bulls (10 ± 2.2 months of age; 219 ± 11.7 kg) were finished in a feedlot with one of five different treatments: CON, control (no essential oil); CLO450, clove essential oil (450 mg/kg); CLO880, clove essential oil (880 mg/kg); CIN450; cinnamon essential oil (450 mg/kg); and CIN880, cinnamon essential oil (880 mg/kg). Instrumental meat quality attributes and consumer acceptability aspects (visual and sensory) were assessed during meat ageing and display. The inclusion of clove essential oil showed (P = 0.033) a quadratic effect on lipid oxidation in meat evaluated under display conditions. Level of cinnamon essential oil affected (P < 0.05) pH, shear force, and meat colour. On the other hand, the diet had no effect (P > 0.05) on sensory or visual acceptability. Ageing (7 days) enhanced (P < 0.05) sensory acceptability attributes. Globally, the addition of essential oil in bull diets can be an alternative to reduces lipid oxidation without modifying sensory acceptability attributes., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The present study estimated genetic parameters and evaluated the genetic and phenotypic correlations between meat quality characteristics of Nellore cattle evaluated at different anatomical points of the longissimus. Data from 1329 Nellore young bulls were used to evaluate, in the 5th and 12th ribs, marbling score (MAR), shear force (SF), cooking weight losses (CWL) and intramuscular fat (IMF). In addition, the subcutaneous fat thickness was measured at the 12th rib (SFT 12 ) and between the last lumbar and the first sacral vertebrae (SFT LR ), in the separation of loin and round. Results yielded moderate heritability coefficients for evaluated characteristics, except CWL. High genetic correlations (0.61) were found between measurements of SFT 12 and SFT LR . MAR, IMF and SF were evaluated at the 5th and 12th rib. Meat quality and subcutaneous fat thickness measured at different anatomical points of the longissimus are genetically correlated and can be used in genetic selection programs to improve meat quality characteristics in Nellore cattle., Competing Interests: Declaration of Competing Interest The authors declare no conflicts of interest., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Water restriction periods were evaluated in crossbred lambs (n = 32) distributed in one of four treatments: without water restriction, water restriction for 24, 48 and 72 h. The water restriction for 72 h reduced the water and dry matter intakes, body weight at slaughter and hot and cold carcass yields. Water restriction did not affect the weight of the carcass cuts and the chemical composition of the meat. The fatty acid EPA increased and DHA reduced with increasing water restriction period. There was an increasing linear effect for meat shear force, with less force (30.5 N/cm 2 ) for sheep meat without water restriction and higher force (45.8 N/cm 2 ) for those with water restriction for 72 h. The period of 24 h of water restriction was the one that promoted the highest similarities in the characteristics assessed to those in animals receiving water ad libitum. Therefore, water restriction periods should not exceed 24 h for feedlot animals in situations of severe water shortage., (Copyright © 2019. Published by Elsevier Ltd.)

Industry requires non-destructive real-time methods for quality control of meat in order to improve production efficiency and meet consumer expectations. Near Infrared Hyperspectral Images were used for tenderness evaluation of Nellore beef and the construction of tenderness distribution maps. To investigate whether the selection of the region of interest (ROI) in the image at the exact location where the shear force core was collected improves tenderness prediction and classification models, 50 samples from Longissimus muscle were imaged (1000-2500 nm) and shear force were measured (Warner-Bratzler). The data were analyzed by chemometric techniques (Partial Least Squares together with discriminant analysis - PLS-DA). Classification models using local ROI presented better performance than the ROI models of the whole sample (external validation sensitivity for the tough class = 33% and 70%, respectively), but none could be considered as successful model. However, the more general model had better performance in the tenderness distribution maps, with 72% of predicted images correctly classified., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: Breed or genotype is important to consider for developing appropriate eating quality in lamb. The objectives of this study were to compare physical and chemical parameters and sensory acceptance of longissimus lumborum (LL) muscle from six lamb breed types economically important to the Brazilian sheep-raising chain., Results: No difference (P > 0.05) among samples was found in relation to L(*) , a(*) and b(*) parameters. However, differences were detected in shear force for the LL muscle produced by different breeds (P < 0.05), where animals without definite breed (WDB) showed higher shear force, whereas the lowest levels were observed for breed Hampshire Down, followed by Ile de France and the Dorper/Santa Inês cross-breed (Dorper/SI). In relation to sensory acceptance, no difference (P > 0.05) was detected in aroma attribute for all breed types tested. For the attributes texture, juiciness, flavor and overall quality, differences were detected (P < 0.05), Dorper/SI, Hampshire Down and Suffolk cross breeds received the best scores, while Santa Inês received intermediate evaluations, and Ile de France and WDB were the least accepted., Conclusion: Under the conditions evaluated in this study, meat from Dorper/SI and Hampshire Down cross-breeds showed better eating quality, satisfying most consumers., (© 2014 Society of Chemical Industry.)

The ASAP1 gene is located in a QTL region for meat production traits and to access the role of the ASAP1 gene, the association between a SNP in this gene and production traits in beef cattle was studied. For this, about 270 steers of reference families of Nelore breed were used. The investigation of marker effects on the traits was performed using a mixed model under the restricted maximum likelihood method. Novel association of a SNP in the ASAP1 gene and shear force measured at 24 h post mortem (P≤0.0083) was described in this population of Nelore cattle. This polymorphism accounted for 1.13% of the total additive variance and 17.51% of total phenotypic variance of the trait, suggesting that this marker could be used in marker assisted selection., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Carcasses of sixty-three Nellore bulls slaughtered at a commercial beef plant were randomly selected by dental classification (2, 4, 6 or 8 permanent incisors) in order to evaluate the influence of dental maturity on carcass traits and meat quality. Carcasses with 8 permanent incisors (p.i.) had greatest values (P<0.05) of carcass weight and longissimus area. Carcasses with 4 and 6 p.i. presented similar values of rib fat thickness being greater (P<0.05) than the other groups. Carcasses with 6 and 8 p.i. presented greater (P<0.05) values of shear force than the other groups. Conversely, carcasses with 2 and 4 p.i. displayed greater (P<0.05) myofibrillar fragmentation index and collagen solubility. Greatest values of thawing loss were observed in carcasses with 2 p.i. (P<0.05) while carcasses with 8 p.i. presented greatest values (P<0.05) of drip loss. Regarding longissimus color, carcasses with 8 p.i presented greatest value (P<0.05) of b*. Data suggests that dental maturity influences carcass traits and meat quality of Nellore bulls., (Copyright © 2011 Elsevier Ltd. All rights reserved.)