Decrease In Cohesion Research Articles

The Role of Wastewater in Controlling Fluvial Erosion Processes on Clayey Bedrock

In recent decades, fluvial erosion processes in highly anthropized areas are mainly associated with in-stream gravel mining activities or with the presence of artificial reservoirs which have increased the erosive capacity of the river as a consequence of the reduced sediment transport or the modification of the longitudinal profile of the channel. On the other hand, the role of pollutants in the degradation processes of soils with a predominantly clayey component is little known. The present study, through chemical analyses of water and mineralogical–geotechnical analyses of clayey soil samples taken along some river channels in central Italy in correspondence with water treatment plants, highlights how “polluting” elements present in the water can modify the crystalline lattice and consequently, the resistance parameters of the soil itself, making it more susceptible to erosion processes. In particular, significant are the variations of the Plasticity Index, which tends to double in all the samples and the transformations of clayey minerals such as illite and kaolinite, toward montmorillonite and smectite, with consequent breaking of the ionic bonds and decrease of the material cohesion. Although in the cases studied this phenomenon was quantitatively less relevant than the “mechanical” processes described above, it could have a greater impact in the presence of landfills or large production settlements (agricultural or industrial) where the concentration of pollutants can be substantial.

A novel obtaining method and mesoscopic mechanism of pseudo-shear strength parameter evolution of sandstone

The pre-peak microstructure evolution of the material is crucial in determining the strength and failure scheme of the material, but is not captured by the existing shear strength parameters models which focus on post-peak stage information. Novel concepts of pseudo-cohesion and pseudo-internal friction angle that account for both the pre-peak and post-peak stage information were proposed in this study, based on the experimentally observed response of the rock mechanics parameters to an external load (the maximum principal stress). These two parameters were analytically derived as functions of maximum principal strain, with coefficients to be determined (i.e., by applying the Mohr–Coulomb criterion with these parameters to experimental data). The dependence of pseudo-cohesion and pseudo-internal friction angle on the axial strain and confining pressure was investigated. The evolution of the strength parameters was found to relate to the propagation of micro-crack developed in the loading process, as revealed by PFC2D simulations reproducing experiments. The results show that (1) analytical model characterizing the pseudo-cohesion and internal friction angle as the quadratic function of axial strain accurately reflects the mechanical response characteristics of the specimen; (2) before the residual stage, the pseudo-cohesion first increases and then decreases with increasing strain, while the pseudo-internal friction angle increases continuously; (3) for the sandstone specimens studied, the pseudo-cohesion at the peak stress increases by a gradually decreasing rate with increasing confining pressure, while the pseudo-internal friction angle at the peak stress decreases by a decreasing rate with the increasing confining pressure; (4) CPM well characterized the mechanical properties of rock under multiple confining pressures, as the total stress–strain curves and failure modes of numerical specimens reproduced the experimental results. The evolution of rock pseudo-shear strength parameters is closely related to the external load and the generation, propagation, and penetration process of rock cracks. The rock pseudo-shear strength parameters are gradually mobilized with the increasing load, and the propagating of cracks owing to the decrease of mobilizable maximum cohesion and the increase of mobilizable maximum internal friction angle.

Study on Characteristic Strength and Constitutive Model of Red Sandstone under Hydraulic Coupling

The newly built shaft in the western region needs to pass through the deep Cretaceous stratum, where the pores and fissures are developed, the cementation ability is poor, and the surrounding rock is rich in water. Under the coupling effect of the stress field and seepage field, the surrounding rock is easy to deteriorate and loses stability. The hydraulic coupling test of Cretaceous red sandstone was carried out by using the TAW-2000 rock mechanics testing system, and the characteristic strength evolution law of red sandstone was analyzed; Mohr’s circle and strength envelope were obtained by the M–C criterion, and the influence mechanism seepage pressure on red sandstone was explored; and combined with the effective stress principle and M–C strength criterion, a constitutive model under hydraulic coupling was established. Confining pressure limits the development of cracks and strengthens the mechanical properties. The results revealed that red sandstone has the characteristics of low less clay, loose particles, and weak cementation capacity; under the action of water pressure, the cement between particles disintegrates and loses the cementation strength, resulting in a significant decrease in cohesion, and the loss of cementation strength is the internal reason for the softening of red sandstone. The constitutive model based on the effective principle and M–C criterion can better reflect the mechanical behavior of red sandstone under hydraulic coupling. This paper provides a research basis for understanding the microscopic characteristics and hydraulic coupling characteristics of Cretaceous weakly cemented sandstone.

Dough Rheological Properties and Characteristics of Wheat Bread with the Addition of Lyophilized Kale (Brassica oleracea L. var. sabellica) Powder

In this study, the effect of replacing 5 or 10% of wheat flour with lyophilized kale (Brassica oleracea L. var. sabellica) on the rheology of dough and bread characteristics (physical and textural properties, sensory acceptability, staling tendency) was evaluated. The farinographic analysis showed an increase in the development time, index of tolerance to mixing, and water absorption. The share of lyophilized kale in the dough affected changes in its rheological properties, e.g., increased the values of storage and loss moduli with a decrease in the value of the phase shift angle (tan δ) from 0.36 to 0.31 at 1 rad/s. A significant decrease in the values of instantaneous and viscoelastic compliance was also observed, and an increase in the value of zero shear viscosity. The incorporation of lyophilized kale into the dough caused a noticeable decrease in bread volume by about 10%, and porosity, by about 8%, despite the lack of statistical significance. Statistically significant changes were found in pore size and the presence of large pores > 5 mm2 in the crumb, while pores density increased. The enrichment of bread with lyophilized kale influenced a decrease in the brightness of the crumb from 73.7 to 49.5 while increasing the proportion of yellow and green color as a result of a considerable increase in the content of chlorophyll pigments and carotenoids. Bread enriched with lyophilized kale had lower acceptability than the control bread. The enrichment of the bread with powdered kale also caused changes in the texture of the crumb, e.g., the hardness on the first day of the study was 2.14 N in the control bread, while in the bread with 10% kale content it was 6.46 N. In addition, the enriched bread showed a decrease in springiness, cohesiveness, and resilience.

Adjusting Skillset Cohesion in Online Labor Markets: Reputation Gains and Opportunity Losses

In online labor markets, contractors' ability to charge for their services largely depends on their skills. To keep up with shifting labor market needs, contractors often expand their skills with new skills. When the new skills are similar to the contractors' current skills, they often increase skillset cohesion (i.e., the average similarity of skills in a skillset). However, when the new skills have little similarity with contractors' current skills, skillset cohesion decreases. How do such adjustments of skillset cohesion affect contractor value in digital workplaces for short-term work? We argue that skillset adjustments affect market value through changes in the contractor's perceived reputation on the new skills and the additional job opportunities that new skills create. We hypothesize that compared with skills that decrease cohesion, skills that increase cohesion result in reputation gains and opportunity losses. Analysis of a panel data set of 47,638 tasks illustrates that for hourly wages, reputation gains are smaller than opportunity losses; hence, all else being equal, increasing skillset cohesion has a relatively negative effect on wages. However, for hiring rates, the opposite is true: Increasing skillset cohesion increases contractor hireability.

Evolutionary implications of size-selective mortality on the ontogenetic development of shoal cohesion: a neurochemical approach using a zebrafish, Danio rerio, harvest selection experiment

Size-selective mortality may evolutionarily alter life-history as well as individual behavioral and physiological traits. Moreover, size-selective mortality can affect group behavioral traits, such as shoaling and collective properties (e.g., shoal cohesion), which are relevant for finding food and reducing risk of predation. Here, we present experimental evidence using selection lines of zebrafish (Danio rerio) that were exposed to positive (large-harvested), negative (small-harvested), and random (control) size-selective mortality for five generations, followed by eight generations during which harvesting was halted to remove maternal effects and to study evolutionarily fixed outcomes. We investigated changes in shoal cohesion and turnover in monoamines in zebrafish through ontogeny. To that end, we repeatedly measured inter-individual distance in groups of eight fish and the turnovers of dopamine and serotonin in brains of fish from juvenile to the adult stage at 40-day intervals. We, firstly, found that shoal cohesion was overall consistent through ontogeny at group levels suggesting the presence of collective personality. Secondly, we found a decrease in shoal cohesion through ontogeny in the small-harvested and control lines, while the large-harvested line did not show any ontogenetic change. Thirdly, the selection lines did not differ among each other in shoal cohesion at any ontogenetic stage. Fourthly, dopamine turnover increased through ontogeny in a similar way for all lines while the serotonin turnover decreased in the large-harvested and control lines, but not in the small-harvested line. The large-harvested line also had higher serotonin turnover than controls at specific time periods. In conclusion, intensive size-selective mortality left an evolutionary legacy of asymmetric selection responses in the ontogeny of shoal cohesion and the underlying physiological mechanisms in experimentally harvested zebrafish in the laboratory.Significant statementThe evolution of animal behavior can be affected by human activities both at behavioral and physiological levels, but causal evidence is scarce and mostly focusing on single life-stages. We studied whether and to what extent size-selective harvesting, a common selection pattern in fisheries, can be an evolutionary driver of the development of shoal cohesion during ontogeny. We used a multi-generation experiment with zebrafish to study cause-and-effects of opposing size-selection patterns. We quantified shoal cohesion, and serotonin and dopamine turnover in the brain. We found that shoal cohesion emerged as a collective personality trait and that behavioral and physiological responses were asymmetrical with respect to the opposing selection patterns.

Change in the Urban Landscape of the Drakensberg Mountain Region, South Africa: A Case Study of Phuthaditjhaba

The settled landscape in the Drakensberg Mountain region of South Africa is characterized by increasing urbanization. Some of the supposedly rural settlements in the region have experienced increasing change in their landscapes over the last 3 decades, resulting in significant land use and land cover (LULC) changes. Among such settlements, Phuthaditjhaba and its environs are slowly becoming a metropolitan area. Based on conceptual considerations regarding sustainable urban development, we assessed LULC change using 4 Landsat images from 1989, 1999, 2009, and 2019 and a combination of unsupervised and supervised classification methods. The images were classified into 4 LULC classes. Between 1989 and 2019, the urban built-up area in Phuthaditjhaba increased from about 5% to 19%, representing a total increase of 270%. However, the greatest increase in land cover was in bare surface at the expense of vegetated areas, including farmland, which decreased from about 45% to 15%. The increase in bare surface could be due to fires. Built-up areas also increased due to a consistent increase in population density in the study area. We further described spatial patterns in LULC using selected landscape metrics. A decrease in patch density (PD) and cohesion, coupled with constant edge density (ED) and an increase in the fractal dimensional index (FDI), indicates fragmentation and less connectivity between 1989 and 1999; we interpret this as a sign of unsustainability. An increase in PD and cohesion and fluctuations in ED and FDI show that land patterns were more aggregated between 2009 and 2019. At the class level, an increase in PD, cohesion, and ED also showed more aggregated land patterns, which was confirmed by the mean patch size. The FDI revealed greater connectivity, which we also interpreted as unsustainable because of the increase in bare surface and built-up areas. Integrative coplanning and comanagement of land use and allocation are needed to ensure sustainable development.

Ultrasound-assisted extraction of oil from hempseed (Cannabis sativa L.): Part 2.

Oilseed-matrix consolidation is a crucial factor when talking about oil expression because, as the cake consolidates, the coefficient of permeability inevitably decreases. Thus, any treatment that extensively ruptures cell walls reduces rigidity and hardness of the oilseed press-cake, while improving the oil expression. Such process intensification was investigated in the present study through the introduction of the ultrasound (US) technology. Screw pressing of Cannabis sativa L. seeds was operated using a pilot scale equipment set at three different pressures (low, medium and high) to understand the correlation with the ultrasound effectiveness. Samples of non-exhausted press-cakes were tested for objective instrumental indices of compressibility and oil expression yields prior and after the US treatment. US led to a drag resistance reduction within press-cakes, improving oil flowability through a decrease in the material cohesiveness and adhesiveness. Consistently, sonication favoured oil extraction yields and oil antioxidant capacities, which increased with respect to the untreated samples, respectively equal to +19.2% and + 29.4% for the press-cake screwed at low pressure, to +21.8% and + 49.3% at medium pressure, and to +15.4% and +0.5% at high pressure. Overall, US highest effectiveness was accounted for samples screwed at medium pressure. Press-cake compressibility can be well described by macroscopic texture parameters; indeed, their decrease is linked to higher oil expression efficiencies. Sonication can help boosting oil extraction yields reducing drag resistance within the mechanical screwing equipment. These outcomes offer good potentials for US application in the hempseed technology and, more extensively, in the oil seed industry. © 2022 Society of Chemical Industry.

Study on Strength Attenuation Characteristics of Residual Expansive Soil under Wetting-Drying Cycles and Low Stress and Its Relationship with Shallow Landslide

The rapid development of expansive soil fissures and the attenuation of strength under the action of repeated atmospheric wetting-drying cycles have a very adverse impact on the shallow stability of expansive soil slope. In this study, shear strength test and fissure observation test were performed on typical residual expansive soil specimens at various wetting-drying cycles and low stress. The results show that the shear strength index of residual expansive soil should be obtained according to the high and low stress sections, respectively. The cohesion of the three residual expansive soils decreased to a similar low value range (0~5 kN) at multiple wetting-drying cycles and low stress; the attenuation of cohesion is the main cause of shallow slope collapse. The fissure rate of the specimen surface increases with the increasing number of wetting-drying cycles, and increasing the dry density can significantly inhibit the development of fissures. The repeated wetting-drying cycles leads to the rapid development of slope fissures from the surface to the inside, destroys the internal natural structure of undisturbed expansive soil, reduces the cementation between soil particles, and leads to the decrease of soil cohesion. For slope stability analysis of residual expansive soil, the strength parameters of the specimens with multiple wetting-drying cycles and internal fissure network should be selected according to the overburden pressure of the slope sliding surface. The research results provide a theoretical basis for the stability analysis of shallow landslide of expansive soil slope and slope protection design.

Relationships in context and contexts of relationship: a normative transition at the end of Secondary Education

High school is an institution where teens spend a large part of their time. Consequently, in this context, a dense network of relationships tends to be formed during the period of study at the institute. However, at the end of secondary school, this set of contextualized relationships begins to disintegrate. In this study, we analyze the transition from high school to university of a cohort of high school students. First, we interviewed all the students who were in their last year of high school at an institute in the province of Seville (n = 69). A year and a half later, we interviewed them again when many of them were already studying at university (n = 57). Using a hybrid research design, we collected personal network data from each interviewee in the context of a longitudinal whole network design of the entire cohort analyzed. The results show a decrease in the structural cohesion of the networks, both for personal networks and for the complete network. Furthermore, less cohesive personal networks seem more likely to experience short-term changes in ecological transition processes. In the discussion we reflect on the impact of educational transitions on friendship relationships.

Experimental Study on Effects of Aging Time on Dry Shrinkage Cracking of Lime Soils.

The effect of aging on the internal mechanism of the dry shrinkage cracking of lime soil was studied from the perspective of macroscopic cracking phenomenon and microscopic composition change, and the reasonable aging time of lime soil was determined. Large numbers of cracks often occur in buildings constructed using lime soil, which impacts sustainable development and building environmental protection. This study explored the influence of aging time on the mechanical properties and shrinkage cracking of lime soil. The influence of aging time was evaluated using a triaxial compression test; using the dry–wet cycle, sieving, pH, and other tests, the influence of aging time on volume crack rate, expansion shrinkage rate, particle size distribution, and pH was analyzed. Scanning electron microscopy and X-ray diffraction experiments were used to analyze changes in the lime soil particle structure for different aging times and the formation of new substances. The results show that as aging time increases, the stress–strain curve of the soil softens significantly, shear strength deteriorates, and cohesion decreases. When the aging time is 6 h, the expansion rate and shrinkage rate at the center of the soil sample are the maximum. The volume fracture and expansion shrinkage rates decrease first, and then plateau with aging time, with the changes remaining stable after 72 h; these rate decreases are positively correlated with the change rate of pH. The formation of Ca(OH)2 affects the sample pH, and the changes in pH, Ca(OH)2, and CaO tend to be stable. With an increase in aging time, the proportion of particles of a size less than 0.1 mm decreases, and that of particles of size 0.1–0.5 mm increases. After 72 h of aging, the particle size proportion remains unchanged. Reasonable aging time can, thus, reduce the hydration reaction of lime, improve particle agglomeration effects, and reduce the crack development of the soil.

Mechanical effect of clay under the acid-base action: A case study on montmorillonite and illite

To study the mechanical effect of clay under acidic and basic conditions, typical clay minerals, montmorillonite and illite, were taken as the main research objects in this study. The variation law and mechanism of the cohesive force and internal friction angle were studied by immersing the remoulded soil in HNO3 solution with pH = 3 and NaOH (alkaline waste liquid) with pH = 13.5, respectively. It was found that, under acidic conditions, a corrosion reaction between clay minerals and nitric acid occurred. Except for the medium-term, the cohesion generally shows a decreasing trend, and the internal friction angle has little change. Under alkaline conditions, the cohesion of montmorillonite-quartz sand remoulded soil decreased briefly in the early immersion stage of and increased in the middle and late stages. The internal friction angle increases steadily with the extension of immersion time. The cohesion of illite-quartz sand remoulded soil also decreased first and then increased, while the internal friction angle changed little. X-ray diffraction analysis shows that montmorillonite and illite will corrode under acidic conditions, and no new material will be generated, resulting in a decrease in soil cohesion. Under alkaline conditions, montmorillonite was seriously depleted, resulting in the formation of zeolite minerals (zeolite X, garronite) and new cement hydrated calcium silicate CSH (xonotlite). Strong alkali reacts with illite to generate sodium metaaluminate (NaAlO2) and liquid cement Na2SiO3 (sodium silicate). The formation of new cements is the main reason for the increase in cohesion under acid-base conditions, and chemical corrosion and ion exchange cause a decrease in cohesion.

Valorization of Garlic Peel as a Potential Ingredient for the Development of ValueAdded Rice Based Snack Product Pukhelein

The present study was designed to develop and evaluate the nutritional, functional, sensory properties and texture profile data of garlic peel powder fortified viz. 2%, 5% and 10% value added pukhelein and compared with control sample. Garlic peel showed crude fiber, carbohydrate and ash content viz. 60.57%, 21.71% and 16.34%, total phenolic content (TPC) of 108.79 µg/ml GAE, total flavonoid content (TFC) of 33.27 mg Quercetin/ml and antioxidant activity (33.38 mg/ml) respectively. 5% formulation exhibited the highest crude fiber, protein content, TPC (326.6 µg/ml GAE), TFC (91.38 mg Quercetin/ml) and total antioxidant content (54.68 µg/ml).Sensory evaluation data showed good result in 5% formulation in terms of appearance, texture and taste. Texture profile analysis showed that a considerable decrease in hardness, springiness, cohesiveness, gumminess and chewiness and resilience. The outcome of the study revealed that 5% garlic peel powder fortified pukhelein exhibited the best result among all formulations.

Determining trigger factors of soil mass failure in a hollow: A study based in the Sichuan Province, China

Soil mass failure disasters are among the most destructive disasters in mountainous areas worldwide, and they continue to receive significant attention in the literature. However, factors that influence soil mass failure in hollows have not been explored via experimental approaches. In this study, we conducted a series of indoor hollow–flume experiments to exhibit how the three factors, namely, initial moisture content, slope angle, and clay content, influence the collapse of soil mass under surface runoff conditions. Our findings revealed that the major processes causing soil mass failure were internal seepage erosion resulting from subsurface runoff, migration of fine particles, development of tension cracks, increase in pore water pressure, and decrease in cohesion. Fluctuations in pore water pressure were characterized by two main trends: (1) an abrupt rise under static liquefaction and (2) a decrease before failure due to dilatancy. The time required for soil mass failure first decreased and then increased with the increase in moisture content. The soil mass with an initial moisture content of ∼12.5% was more critical to the failure. In addition, the time required for soil mass failure decreased with increasing slope angle, revealing a slope angle of 40° to be more prone to failure. The buildup of pore water pressure was found to increase with clay content; soil with a clay content of ∼7.5% required the shortest amount of time to initiate slides. Thus, our results provide a thorough insight into the processes and factors involved in the initiation and development of soil mass failure in hollow areas, which can be used by public agencies to improve monitoring, early warning, and forecasting systems. Notably, our study can help identify risk-prone source areas, and sensors can be installed to monitor potential mass failure locations.

The slow release behavior of soy protein isolate/κ-carrageenan composite hydrogel: Effect of konjac glucomannan

Composite hydrogels are known for their potential applications in drug delivery fields. Pure κ-carrageenan (KC) hydrogels have a drug burst release behavior, which greatly limit their applications. In this study, konjac glucomannan (KGM) was used to further improve the properties of soy protein isolate (SPI)/KC composite hydrogels. The results showed that the viscoelasticity of the composite hydrogels increased at KC/KGM ratio 9:1 due to the increase of hydrogen bond interaction. Excessive addition of KGM in composite hydrogels led to the increase in frequency dependence and gel network cavity as well as the decrease in gel cohesiveness. In vitro study on glucose release behavior of composite hydrogels showed that the glucose slow release behavior was enhanced by a small amount of KGM incorporation and had highly positive correlation with the gel viscoelasticity. These results suggested that KGM had the potential to enhance the properties and drug release characteristics of composite hydrogels.

Mechanical Properties of Tensile Cracking in Indium Tin Oxide Films on Polycarbonate Substrates

The electro-mechanical behaviors of transparent conductive oxide film on polymer substrate are of great concern because they would greatly affect the stability and lifespan of the corresponding devices. In this paper, indium tin oxide (ITO) films with different thicknesses were deposited on a polycarbonate (PC) sheet; meanwhile, in situ electrical resistance, in situ scanning electron microscopy and profilometry were employed to record the electrical resistance, morphologies and residual stress in order to investigate the fracture behavior and electrical-mechanical properties of ITO films under uniaxial tension loading. The electrical resistance changes, crack initiation, crack propagation and crack density evolution of ITO films were systematically characterized by in situ tests. Three fracture stages of ITO films were summarized: Ⅰ crack initiation, Ⅱ crack propagation, Ⅲ crack saturation and delamination. The crack initiation and electrical failure in a thinner ITO film occurred at relatively higher applied tensile strain; namely, the ductility of the film decreased as the film thickness increased. Residual compressive stress was recorded in the ITO films deposited on PC at room temperature and increased as the film thickness increased. Intrinsic crack initiation strain (CIS*) showed an opposite thickness dependence to residual strain (εr); the increase in residual compressive strain was counteracted by the decrease of intrinsic cohesion, leading to an overall decrease in effective crack initiation strain (CIS) when the film thickness increased. In addition, integrated with a formulated mechanics model and the analysis of the three fracture stages under tension, the fracture toughness and interfacial shear strength were quantitatively determined. As the film thickness increased (in the range of 50~500 nm), the fracture toughness decreased and the films were more prone to crack, whereas the interfacial shear strength increased and the films were less likely to delaminate.

The Study of Influence of Freeze-Thaw Cycles on Silty Sand in Seasonally Frozen Soil Regions

Freeze-thaw cycles can cause varying degrees of damage to expressway, in order to study the influence of freeze-thaw cycles on silty sand of expressway in Qinghai seasonal frozen soil regions, triaxial compression tests were carried out on silty sand under different initial freeze-thaw temperatures and freeze-thaw cycles. The stress-strain curve, secant modulus, cohesion, internal friction angle, dynamic shear modulus, and dynamic damping ratio of soil after freeze-thaw cycles were analyzed and studied. The experimental results show that the number of freeze-thaw cycles has different effects on the stress-strain curves at different initial freezing temperatures. With the increase of freeze-thaw cycles, the secant modulus of soil increases and changes in wave shape. The cohesion decreases and the internal friction angle decreases nonlinearly. The dynamic shear modulus and damping ratio do not change significantly. The change of freeze-thaw cycles will also affect the physical structure of the soil itself. The change of freeze-thaw cycles will also affect the physical structure of the soil itself. It will change the mosaic form of soil particles, the shape of soil particles, the size of soil particles and pores, and also make the redistribution of water in the soil.

Shearing Performance of Natural Joints with Different Roughnesses under Direct Shearing Tests

Roughness is one of the major characteristics of natural fracture in hydrocarbon and geothermal reservoirs, which has a significant influence on the activation of fractures during hydraulic stimulation. The main purpose of this study is to investigate the effect of different roughnesses and high normal stresses on shear behaviors of rock joints. To do this, replicas of natural rock joint surfaces were constructed using the 3D optical scanning and 3D rigid engraving technique. Direct shear tests were performed on rock joint replicas with three joint roughness coefficient (JRC) indices (i.e., 1.42, 4.98, and 7.96) at two high normal load conditions (i.e., 15 and 30 MPa). The results show that the shear strength dependence on surface roughness is similar at normal stresses of 15 and 30 MPa. In addition, JRC-JCS shear strength criterion can reasonably describe the peak shear strengths that obtained from experimental curves, and the peak shear stresses have a positive correlation with JRC values at both normal stresses. Moreover, at normal stresses of 15 and 30 MPa, the shearing mechanism of joints with different JRC values is asperity shearing off. Results also show that the friction coefficient of joint surface increases as joint roughness increases, and higher normal loads may lead to a decrease of apparent cohesion, which weakens the residual strength during the slip. The results of this study improve insight into the natural fracture activation behavior during hydraulic fracturing.

Recycling of paper/wood industry waste for hydromechanical stability of expansive soils: A novel approach

This article presents a sustainable solution to repurpose paper/wood industry waste as a geotechnical construction material. A novel lignosulphonate (LS)-based composite admixture (CA) was used in this study to cope with construction problems pertaining to expansive soils. Surface water infiltration in terms of rainfall and surface water irrigation are the prime factors that cause volumetric change behavior and a drastic reduction in shear strength due to loss in suction that eventually causes failure in expansive soils. Such failures are comprised of complex hydromechanical phenomena and their remediation requires special attention. In this context, this study for the first time deals with the use of LS-based CA as a remedy to such failures in expansive soils considering the hydromechanical properties. To better understand the hydraulic response, the specially designed soil-column model tests (SCMTs) were conducted. Besides, different geotechnical experiments and microstructural analyses were carried out to analyze the hydromechanical behavior of CA treatment against the varying degree of saturation (Sr). The results showed that LS-based CA treatment increases the water holding capacity over a suction range of 78.4 kPa and air entry value (AEV) by 33%. Also, the SCMT showed that the wetting-front depth (WFD) at full saturation in CA treated expansive soil was 4–10% quicker than untreated expansive soil. In addition, for the increase in Sr from optimum to 100%, the decrease in cohesion (c) value for untreated and treated soil was found to be 88% and 39.8%, and the increase in compressibility was 37% and 17%, respectively, highlighting better resistance against Sr. Whereas, the swelling potential was completely eradicated with a significant reduction in volumetric shrinkage by 43% compared to untreated soil. The microstructural analyses showed the development of apparent aggregation with the Sr in untreated expansive soil, whereas the CA treatment-induced better structure with bigger size particles with disrupted inter and intra assemblage pore spaces. The results showed that LS-based CA manifests substantial hydromechanical stability against variation in Sr. Overall, this study provides the scientific basis to the practitioners for the pragmatic use of LS-based CA in treating expansive soil problems.

The Effects of Frying Method and Oil Type on the Quality Attributes of Turkey Nuggets and Frying Oils

AbstractThe aim of the study is to determine the effects of frying under standard atmospheric and pressure conditions on some quality characteristics of turkey nuggets. Turkey nuggets are fried under atmospheric and pressure conditions using sunflower or hazelnut oil. Pressure frying decreases the thiobarbituric acid reactive substances (TBARS) value of turkey nuggets while sunflower oil increases this value. Under atmospheric conditions, nuggets fried with hazelnut oils show higher moisture content than hazelnut oil. The pH is affected by the type of oil. The frying under pressure results in a decrease in the internal and external a* value of nuggets. Under pressure conditions, the use of hazelnut oil increases the external a* value. The application of pressure also causes an increase in the external L* value in the presence of sunflower oil. These treatments also show higher hardness, springiness, gumminess, and chewiness values compared to atmospheric condition. The use of sunflower oil causes a decrease in resilience, cohesiveness, springiness, and chewiness values. After frying, hazelnut oil shows lower peroxide and total polar material values than sunflower oil. However, peroxide value and total polar material are not affected by frying method.Practical applications: Color and texture are very important factors for the quality of nuggets. Pressure and atmospheric conditions show different effects on color parameters. Frying under pressure conditions decreases the external L*, which is an important quality parameter. Hazelnut oil shows lower TBARS value than sunflower oil. Moreover, pressure application causes a decrease in TBARS value. Frying process under pressure decreases the hardness and adhesiveness, while it increases the juiciness of product. On the other hand, the use of hazelnut oil as frying oil shows less changes in peroxide and total polar material during frying than sunflower oil, but the frying method and oil type interaction has no significant influence on these parameters.