Long-term Integrity Research Articles

Assessment of the structural integrity of glulam using modal analysis and finite element updating

The increasing adoption of glued laminated timber (Glulam) as an environmentally conscious material in construction has been driven by its excellent structural properties and lower carbon footprint compared to other conventional materials. However, its organic nature underscores the need to ensure the long-term integrity of these glulam structures. This paper proposes a novel approach to non-destructive testing (NDT) through the combined application of modal analysis and updated finite element modelling. These advanced techniques allow a more accurate and detailed assessment of the structural condition of glulam. Modal analysis identifies changes in natural frequencies and vibration modes caused by potential material degradation, providing valuable structural health information without compromising the integrity of the material. To achieve this objective, the paper proposes to compare the real values measured in the modal analysis with those obtained from the numerical model by formulating an objective function that measures the error between the two. The differences between the two models are reduced using techniques based on Particle Swarm Optimization (PSO). The work presents a specific formulation aimed at achieving greater efficiency in the search for defects in this material. The results of the proposed method are verified by laboratory tests. For this purpose, glulam samples with different defects were tested and their identification was verified by updating the finite element models, demonstrating the ability and accuracy of the method to identify areas where the structural stiffness has decreased due to deterioration.

Damage Classification Using CNN-Based Model for Multi-Part Strengthening System

Strengthening and retrofitting systems, including FRCM (Fiber-Reinforced Cementitious Matrix), play a vital role in improving the durability and safety of structures facing challenges such as aging, increased loads, or seismic risks. To ensure the long-term integrity and performance of these structures, it’s crucial to monitor the health of repaired structural components. Acoustic emission (AE) is a non-destructive and passive technique that involves the detection and analysis of stress waves emitted by various material components undergoing damage. In this particular research, the study focuses on the classification of damage in different material components of RC (Reinforced Concrete) beams strengthened with FRCM. This classification is achieved using a convolutional neural network (CNN) model that utilizes image-based waveform data from the AE testing. The study collected waveforms from four distinct failure modes: fabric-matrix debonding, fabric rupture, tensile cracking in the cementitious matrix, and yielding of steel. These waveforms were used to train the CNN model. Each waveform was converted into a Discrete Wavelet Transform (DWT) scalogram as an input into the model. The model demonstrated prediction accuracy of approximately 95% during training. The pre-trained model was further employed to classify failure mechanisms with a separate test dataset with an accuracy of approximately 87%, which is considered satisfactory considering added noise to the test dataset.

Constructing a zero leak landfill cell

Engineered landfill barriers are the last line of defence in protecting precious groundwater resources from contamination. A landfill cell without any leaks at the conclusion of construction is the exception rather than the rule. From design to materials testing to installation practices and contractor care, all of these elements contribute to both the short and long-term integrity of the lining system. Electrical leak location (ELL) methods can be used to detect leaks in installed landfill cells after construction so that leaks can be repaired before a landfill cell begins filling operations. However, the thorough testing of landfill cells using ELL can be complicated by their complex configuration. The dipole method, employed after cover material placement, requires electrical isolation of the cover material, which is difficult to achieve with a landfill expansion cell configuration. Additionally, employing only this type of testing can leave the tie-in area untested, which is a critical area prone to damage. This paper provides solutions for complete landfill expansion cell testing, including a relatively new testing methodology (ASTM D8265, [1]), which provides protocol for verifying that a geomembrane has been successfully installed with no leaks. A case study is included to show how ASTM D8265 can be used to provide documentation of a zero-leak condition of a landfill cell after construction. Common elements of design, geomembrane installation, and quality assurance are discussed in order to provide a road map of how to reach a zero-leak condition at the end of a landfill expansion cell construction project. This paper can be used as a guide to constructing a zero-leak landfill cell using state-of-the art construction practices and ELL testing methodologies.

Technology Focus: Well Integrity (January 2024)

The context of last year’s Well Integrity Technology Focus was the repurposing of existing oil and gas wells for carbon storage, flow-wet material conformity, and associated integrity risks. Typically, oil and gas producing wells are abandoned toward the end of their life cycles with reservoir pressures depleted compared with the virgin pressures. Carbon capture and storage (CCS) projects, however, present different operating conditions. First, the pressurized containment sites have a higher life expectancy, say, between 50 and 100 years. Second, the containment pressure is possibly higher than the virgin pressure. The overpressure limit is dependent on several factors, especially the caprock sealing capacity. It goes without saying that CCS storage in wells requires long-term integrity (i.e., for the entire project life cycle). It is well-known that barriers such as cement and casings deteriorate over time. Deterioration of barriers may be accelerated by chemical reaction with carbon dioxide or thermal cycling. Hence, these storage sites could present unique life-cycle integrity risks perhaps never experienced by the oil and gas industry. To further explain the scenario, a possible breach of the confining strata resulting in pressure communication to the overburden means CO2 finding its way through the deteriorated well barriers of any active or shut-in well, resulting in CO2 ingress to the upper formations; groundwater contamination; or, in a worst-case scenario, appearance at the surface. Therefore, one of the important subsurface aspects of a CCS site is the presence of two seals (i.e., primary and secondary), with sealing capacity of both caprocks characterized robustly. Lack of double barriers or improper characterization of these confining strata could present a scenario wherein CO2 flows into overburden (i.e., above the caprock). The wells’ outer annuli then could become a potential path of least resistance for CO2 to migrate further up. Such situations can defy the primary objective of CCS projects and can require mitigation with proper attention to detail following the “as low as reasonably practicable,” or ALARP, principle. The scenario discussed is unique and complex and requires continuous managing and monitoring of CCS storage sites. Furthermore, the role of artificial intelligence and automation is seen as imperative during the operational stage of the project. In addition to the primary paper selections synopsized here, three SPE papers focusing on artificial intelligence and machine learning as tools for well integrity management are recommended as alternates for further reading. Recommended additional reading at OnePetro: www.onepetro.org. SPE 212479 Improve Well Integrity Using an Annular Barrier AI Tool by Eirik Time, Equinor, et al. SPE 211537 Transforming Production-Phase WIMS to a Game Changer Smart Well Integrity Monitoring System With Real-Time Automated Engineering Analytics by Mohammed Jasem, ADNOC, et al. SPE 216600 Paradigm Shift in Well Integrity Management Through the Use of Autonomous Wireless Well Intervention Robots by Julio Q.M. Guedes, Ouronova, et al.

Resonance capture and resonance jump of the space debris with high area-to-mass ratio in the synchronous orbit region

Space debris near the synchronous orbit poses significant collision risks to spacecraft in this area. Therefore, it is necessary to analyze the orbital dynamics of space debris in order to predict its orbital evolution and prevent it from colliding with the spacecraft. Due to the combined effect of the dissipative forces and Earth’s 1:1 tesseral resonance, the space debris with high area-to-mass ratio near the synchronous orbit exhibits two special dynamical behaviors: resonance capture and resonance jump. By using a simplified model, this paper analyzes in detail the orbital evolution of the debris of the resonance capture and resonance jump, and explores the conditions for their occurrence. It is found that the dynamical behavior of space debris around the resonance capture or resonance jump is highly sensitive to its initial conditions. In addition, the long-term direct numerical integrations with the full dynamical model for the orbital evolution of the debris are performed. The difference between the phase space parameters of the resonance capture and resonance jump for space debris is discussed, and the pendulum-like oscillation of the resonant angle is also studied.

Analysis of the Effect of Supply Chain Management and Local Wisdom on the Competitiveness of Coastal Fishing Communities in North Minahasa District

Supply Chain Management is an integrative method or approach to manage the flow of products, information, and money in an integrated manner involving parties from upstream to downstream consisting of suppliers, factories, distribution networks and logistics services. The supplier is one of the most important links in determining product quality and the speed with which the product reaches the consumer. In the capture fisheries industry in North Sulawesi, coastal fishing communities in North Minahasa District are one of the spearheads of the success of the supply chain for the capture fisheries industry because they function as suppliers for the fish processing industry in North Sulawesi. The purpose of this study was to analyze the influence of Supply Chain Management, namely the variables of technical and managerial assistance, information sharing, trust, long-term relationships, and process integration on the competitiveness of coastal fishing communities in North Minahasa District and local wisdom on competitiveness. This research uses causal associative research. The analytical method used is Multiple Linear Regression Analysis. The results showed that technical and managerial assistance, information sharing, trust and local wisdom had a significant effect on the competitiveness of coastal fishing communities in North Minahasa District, while long-term relationship variables and process integration did not significantly affect the competitiveness of coastal fishing communities in North Minahasa District.

The Mechanism of Titanium Hydride Formation on Grade-2 Titanium

ASTM Grade-2 titanium (Ti-2) is a commercially pure grade widely used for its corrosion resistance in extreme environments. Therefore, Ti-2 has found applications within industries such as oil and gas, chemical processing, and nuclear power, where it is used for components such as reaction vessels, piping, and heat exchangers. Challenges with the fabrication process result in relatively high amounts of iron in commercial materials such as Grade-2, Grade-7, and Grade-12, which all have a maximum tolerance of 0.3 wt.% iron.The amount of iron present in titanium has been shown to have a significant effect on the microstructure and corrosion behaviour[1]. For example, Fe will precipitate and form TixFe intermetallic particles (IMPs) along grain boundaries if the local solubility limit is exceeded. Many of the corrosion processes (e.g., crevice corrosion) that determine the long-term integrity of Ti are strongly affected by the presence of IMPs[1]. Another detrimental corrosion scenario is the formation of titanium hydride (TiHx), which can precipitate on the surface and/or in the bulk material when the hydrogen concentration is high enough. Formation of TiHx phases increases the susceptibility of the metal to cracking, as the hydride is less ductile than the metal and its formation results in a strain-inducing volume increase within the matrix. Despite the proven importance of IMPs to the corrosion behaviour of Ti, and the detrimental effects of hydride formation on the material’s integrity, a direct relationship between IMPs and TiHx formation is not well established. There is some evidence that titanium hydride formation initiates at IMPs[2], but a complete mechanistic understanding is missing.In this study, the initiation and propagation mechanism of TiHx formation on Ti-2 is being investigated over a 24-hour period. Hydrides were grown galvanostatically in a simulated crevice corrosion environment. The surface was analyzed at various times using field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), focused ion beam (FIB) milling, and X-ray diffraction (XRD). By visualizing TiHx within the matrix using FE-SEM, we determined that titanium hydride formation initiates at IMPs and then grows both laterally and vertically around the IMP. After reaching a depth of ~ 4 µm below the surface of the IMP, the hydride stops growing vertically but continues to spread laterally across the Ti grain face until full surface coverage is reached. Finally, a steady-state condition is reached, in which hydride is present as a uniformly distributed layer across the surface with a thickness of ~ 4 μm. Additionally, the electrochemical potential values during the galvanostatic hydride growth process and the amount of hydride detected using XRD both support the hypothesis of the hydride growing rapidly before reaching a limited thickness.[1] X. He, J. J. Noël, D. W. Shoesmith, Corrosion 2004, 60, 378–386.[2] Q. Tan, Z. Yan, H. Wang, D. Dye, S. Antonov, B. Gault, Scr. Mater. 2022, 213, 114640.

Use of physician-modified inverted limb in conjunction with Zenith fenestrated stent graft to rescue failed previous endovascular and open repair

ObjectiveTo evaluate outcomes and performance of inverted limbs (ILs) when used in conjunction with Zenith fenestrated stent grafts (Zfens) to treat patients with short distance between the lowest renal artery (RA) and aortic or graft bifurcation (A/GB). MethodsThis study was a multicenter, retrospective review of prospectively maintained database of patients with complex aortic aneurysms, failed endovascular aneurysm repair (EVAR), or open surgical repair (OSR) with short distance between LRA and A/GB treated using a combination of Zfen and an IL between 2013 and 2023. Endpoints included technical success, aneurysm sac regression, long-term device integrity, and target vessel patency. We defined technical success as implantation of the device with no endoleak, conversion to an aorto-uni-iliac or OSR. ResultsDuring this time, 52 patients underwent endovascular rescue of failed repair. Twenty (38.5%) of them required relining of the failed repairs using IL due to lowest RA to A/GB length restrictions. Two patients had undergone rescue with a fenestrated cuff alone but developed type III endoleaks. One patient with no previous implant had a short distance between the lowest RA and aortic bifurcation to accommodate the bifurcated distal device, and two patients had failed OSR or anastomotic pseudoaneurysms. The majority (94%) were men with a mean age of 76.8 ± 6.1 years. The mean aortic neck diameter and aneurysm size were 32 ± 4 cm and 7.2 ± 1.3 cm, respectively. The median time laps between initial repair and failure was 36 months (interquartile range [IQR], 24-54 months). Sixteen patients (80%) were classified as American Society of Anesthesiologists class III, whereas four were class IV. Seventy-eight vessels were targeted and successfully incorporated. Technical success was 100%, and median estimated blood loss was 100 mL (IQR, 100-200 mL). Mean fluoroscopy time and dose were 61 ± 18 minutes and 2754 ± 1062 mGy, respectively. Average hospital length of stay was 2.75 ± 2.15 days. Postoperative complication occurred in one patient who required lower extremity fasciotomy for compartment syndrome. At a median follow-up of 50 months (IQR, 18-58 months), there were no device migration, components separation, aneurysmal related mortality, and type I or type III endoleak. Aneurysm sac regression (95%) or stabilization (5%) was observed in all patients, including in four patients (25%) with type II endoleak. ConclusionsThe use of IL in conjunction with Zfen to treat patients with short distance between the lowest RA and A/GB is safe, effective, and has excellent long-term results. The technique expands the indication of Zfen, especially in patients with failed previous EVAR.

Characterizing imbibition and void structure evolution in damaged rock salt under humidity cycling by low-field NMR

The excavation damaged zone (EDZ) of salt cavities for compressed air energy storage (CAES) undergoes daily humidity cycling. This study investigated moisture imbibition and its impact on void structures in differently damaged rock salt in a cyclic humidity environment using periodic low-field nuclear magnetic resonance (NMR) tests. NMR tests were also conducted on centrifuged and saturated specimens to assist with the analysis. Fluid-accessible voids in rock salts encompass mesovoids (2–50 nm) and macrovoids (>50 nm). In the wet stage of the first cycle, imbibition in the mesovoids lagged behind that in the macrovoids, whereas dehydration in the mesovoids was more pronounced and rapid in the subsequent dry stage than in the macrovoids. Throughout the long-term treatment, imbibition persisted, and the macrovoid volume in all three specimens notably decreased, whereas those of the mesovoids slightly increased. Collectively, these effects significantly reduced the fluid-accessible porosity. In our interpretation, the greater viscous force in the mesovoids impeded their imbibition and brine supplementation, resulting in a difference in the tests of the first cycle. The continuous imbibition of brine activated two self-healing mechanisms in the macrovoids: diffusion mass transfer and recrystallization. These mechanisms transformed consecutive macrocracks into isolated voids filled with recrystallized microstructures, effectively transforming macrovoids into mesovoids. In summary, this study characterized the complex imbibition and void structure evolution affected by self-healing mechanisms of rock salt under humidity cycling, offering new insights for evaluating the long-term stability and integrity of CAES salt cavities.

Molecular self-assembled cellulose enabling durable, scalable, high-power osmotic energy harvesting

In recent years, renewable cellulose-based ion exchange membranes have emerged as promising candidates for capturing green, abundant osmotic energy. However, the low power density and structural/performance instability are challenging for such cellulose membranes. Herein, cellulose-molecule self-assembly engineering (CMA) is developed to construct environmentally friendly, durable, scalable cellulose membranes (CMA membranes). Such a strategy enables CMA membranes with ideal nanochannels (∼7 nm) and tailored channel lengths, which support excellent ion selectivity and ion fluxes toward high-performance osmotic energy harvesting. Finite element simulations also verified the function of tailored nanochannel length on osmotic energy conversion. Correspondingly, our CMA membrane shows a high-power density of 2.27 W/m2 at a 50-fold KCl gradient and super high voltage of 1.32 V with 30-pair CMA membranes (testing area of 22.2 cm2). In addition, the CMA membrane demonstrates long-term structural and dimensional integrity in saline solution, due to their high wet strength (4.2 MPa for N-CMA membrane and 0.5 MPa for P-CMA membrane), and correspondingly generates ultrastable yet high power density more than 100 days. The self-assembly engineering of cellulose molecules constructs high-performance ion-selective membranes with environmentally friendly, scalable, high wet strength and stability advantages, which guide sustainable nanofluidic applications beyond the blue energy.

Two-stage assessment: Towards a novel and holistic evaluation of urban geographically isolated wetland sustainability under global warming-induced dryness and loss

Global wetlands are vital for carbon sequestration and providing ecosystem services in sustainable cities. However, urban wetlands, particularly geographically isolated wetlands (GIWs), face threats from climate change and rapid urbanization. The vulnerability of GIWs, considering the critical water flux exchanges with their surroundings, remains unclear. This study proposes a groundbreaking two-stage assessment framework for evaluating GIW sustainability. The first stage quantifies dryness risk by assessing the absence of surface water storage. The second stage evaluates wetland loss risk by examining unsustainable conditions of lacking saturated soil. The framework utilizes a hydrological model incorporated with 20 Global Climate Models (GCMs) under multiple greenhouse gas emission scenarios. Moreover, Taguchi optimization is firstly introduced the hydro-climate field to improve simulation efficiency, with a new modification by a modified robust design. Results indicate an average 26 cm drop in the GIW water table by 2099 under moderate GCM scenarios, with an 86% risk of drying and a 64% risk of transitioning to loss. Notably, GIWs face over twice the risk of loss compared to upland areas, but demonstrate an advantage in water reservation under climate change. By proposing and employing this innovative approach, this research provides valuable insights into the interconnectedness of GIWs, offering a more comprehensive understanding of long-term urban ecological integrity. The findings also contribute to the long-term sustainability of urban wetlands and enhance the resilience of urban ecosystems.

A Tunable Soft Silicone Bioadhesive for Secure Anchoring of Diverse Medical Devices to Wet Biological Tissue.

Silicone is utilized widely in medical devices for its compatibility with tissues and bodily fluids, making it a versatile material for implants and wearables. To effectively bond silicone devices to biological tissues, a reliable adhesive is required to create a long-lasting interface. BioAdheSil, a silicone-based bioadhesive designed to provide robust adhesion on both sides of the interface is introduced here, facilitating bonding between dissimilar substrates, namely silicone devices and tissues. The adhesive's design focuses on two key aspects: wet tissue adhesion capability and tissue-infiltration-based long-term integration. BioAdheSil is formulated by mixing soft silicone oligomers with siloxane coupling agents and absorbents for bonding the hydrophobic silicone device to hydrophilic tissues. Incorporation of biodegradable absorbents eliminates surface water and controls porosity, while silane crosslinkers provide interfacial strength. Over time, BioAdheSil transitions from nonpermeable to permeable through enzyme degradation, creating a porous structure that facilitates cell migration and tissue integration, potentially enabling long-lasting adhesion. Experimental results demonstrate that BioAdheSil outperforms commercial adhesives and elicits no adverse response in rats. BioAdheSil offers practical utility for adhering silicone devices to wet tissues, including long-term implants and transcutaneous devices. Here, its functionality is demonstrated through applications such as tracheal stents and left ventricular assist device lines.

Battery energy storage systems' integration in Baja California Sur, Mexico: A long-term electrical grid assessment

This paper aims to assess the long-term integration of Battery Energy Storage Systems (BESS) in Baja California Sur (BCS), Mexico. First, the electrical grid in BCS is parametrized and modeled to reproduce the actual operational conditions before evaluating long-term expansion scenarios. Eleven scenarios are modeled to assess the integration of BESS under different conditions, such as changes in the level of renewable penetration and restrictions on generation technologies deployment. Our results indicate that BESS in BCS reduce total systems costs and support the development of higher shares of renewable energy technologies across all modeled scenarios, but does not eliminate curtailment in the optimization of the operational strategies. In instances where large volumes of renewable energy deployment take place, up to 22 % can be curtailed, however this still leads to least-cost expansion, and with fewer emissions than with fossil-fuel based scenarios. Transmission expansion occurs in some scenarios, but it is limited to 480 MW total, which in other scenarios can be avoided via BESS investments. Based on the capacity and dispatch results of the different evaluated pathways, a set of recommendations for BCS system operators and decision-makers are provided.

Synergistic Benefits of Motor Control Exercises and Balance Training in Sacroiliac Joint Dysfunction: A Randomized Controlled Trial.

Chronic low back pain, frequently attributed to Sacroiliac Joint Dysfunction (SIJD), remains a prevalent concern in orthopedic and physiotherapy arenas. Despite the recognition of motor control exercises (MCEs) and balance training (BT) as potential rehabilitative measures, studies elucidating their combined efficiency for SIJD are scarce. This research study aimed to ascertain the combined and individual efficacies of MCE and BT in alleviating SIJD symptoms. A double-blinded randomized controlled trial was conducted, enrolling 120 SIJD-diagnosed patients aged 30-60 years. Participants were randomly allocated into four groups: MCEs alone, BT alone, combined MCEs and BT, and a control group receiving usual care. Interventions spanned 12 weeks, with evaluations at the start and end and a 24-week follow-up. Primary outcomes encompass pain intensity (assessed via Visual Analog Scale), functional disability (utilizing the Oswestry Disability Index), and life quality (using the Short Form-36). Post a 12-week intervention, participants receiving combined MCE and BT demonstrated substantial improvements in VAS (Median: 3.5, IQR: 2-5; p = 0.0035), ODI (Median: 15%, IQR: 10-20%; p = 0.0035), and SF-36 scores (Median: 70, IQR: 65-75; p = 0.0035) compared to baseline. In contrast, standalone MCE or BT and control groups exhibited lesser efficacy. By the 24-week follow-up, the combined group maintained their gains, outperforming the other groups. The research tools employed showed high reliability with Cronbach's alpha >0.85. Our findings underscore the superior efficacy of integrating motor control exercises (MCEs) and balance training (BT) for Sacroiliac Joint Dysfunction (SIJD)-related chronic low back pain. This combined approach promises enhanced patient outcomes, highlighting its potential as a primary strategy in SIJD management. Future studies should further explore its long-term benefits and integration with other therapeutic modalities.

Starting flexible, always flexible? The relation of early temporary employment and young workers employment trajectories in the Netherlands

Using register data from Statistics Netherlands (2009–2019), this paper examines whether the first employment contract is related to early career outcomes for a cohort of young workers who entered the Dutch labour market in the period from late 2009–2013. Instead of looking at the timing of isolated transitions between employment states, 6-year-long trajectories are considered to identify differences in early career paths. Applying a Mixture Hidden Markov Model, eight distinct states of employment quality characterized by different contract types and incomes are identified. Transitions between these employment states reveal four early career patterns that differ according to their upward and downward mobility. Our results show that entering the labour market with a permanent contract does not necessarily lead to immediate wage growth, but provides a safeguard against volatile careers with frequent transitions in and out of employment. While entering the labour market with a fixed-term contract facilitates upward mobility, on-call and temporary agency work early in the career may negatively affect long-term labour market integration.

The Perceived Challenges of Resettlement among Syrian Refugees in the United States

This qualitative case study examines the resettlement experiences of Syrian refugees through semi-structured interviews with eighteen Syrian refugees living in Cincinnati, OH, USA. Resettlement experiences reveal challenges to refugees’ long-term integration, address the limitation in state policy practices, and provide insight to meet refugees’ needs. Findings indicate that Syrian refugees’ resettlement generates serious obstacles to their integration, including uninhabitable homes, unsafe neighborhoods, job insecurity and economic instability, lack of language proficiency, and social isolation. The findings also show that the resettlement policies and programs aimed to promote refugees’ self-sufficiency are not compatible with their self- identified needs of Syrian refugees. However, state and local resettlement agencies collaboration with refugees may ease refugees’ transition. Future research may explore the experiences of Syrian refugees who settle in other regions of United States to determine if their experiences differ based on location. Identifying the impact of contextual factors on the resettlement experiences of refugees can help us develop programs and policies that address the subjective needs of both Syrian and other refugee populations.

Crack Localization and Detection in Small-Scale Reinforced Concrete Beams With Smart Technology

Reinforced concrete structures form the backbone of modern civil engineering, yet the emergence of cracks poses a significant challenge to their long-term integrity. The integration of smart sensors and data analytics further augments precision by enabling real-time data collection and analysis, allowing for early intervention. Continuous monitoring, facilitated by remote sensing and wireless communication, ensures a dynamic understanding of crack propagation. To validate the proposed approach, an experimental campaign was conducted using reinforced concrete beams. Three point bending tests were conducted on two small-scale reinforced concrete beams. Different configurations of SEC arrays were used on the two specimens to assess the capacity and limitation of the proposed approach. Results show that the sensing skin was capable of detecting and localizing cracks that formed in both specimens.

Hunting and the Social Lives of Southern Africa’s First Farmers

Perspectives on human–animal relationships are changing in archaeology and related disciplines. Analytical models that distinguish foraging from food production remain popular, but scholars are beginning to recognize greater variability in the ways people understood and engaged with animals in the past. In southern Africa, researchers have observed that wild animals were economically and socially important to recent agropastoral societies. However, archaeological models emphasize cattle keeping and downplay the role of hunting among past farming groups. To address this discrepancy and investigate human–wild animal interactions over the last ~ 2000 years, we examined zooarchaeological data from 54 southern African Iron Age (first and second millennium AD) farming sites. Diversity and taxonomic information highlights how often and what types of animals people hunted. Comparisons with earlier and contemporaneous forager and herder sites in southern and eastern Africa show that hunting for social and economic purposes characterized the spread of farming and rise of complex societies in southern Africa. The long-term cultural integration of wild animals into food-producing societies is unusual from a Global South perspective and warrants reappraisal of forager/farmer dichotomies in non-Western contexts.

Pedagogical Paradigms in the AI Era: Insights from Saudi Educators on the Long-term Implications of AI Integration in Classroom Teaching

This qualitative study explores the perceptions and experiences of Saudi educators regarding the integration of Artificial Intelligence (AI) in classroom teaching. Through semi-structured interviews with a purposively sampled group of teachers, the research investigates initial experiences with AI, anticipated changes in teaching roles, support and training needs, student reactions, and concerns about long-term AI integration. Employing a constructivist grounded theory approach, the study reveals a nuanced understanding of the opportunities and challenges presented by AI in education. Findings indicate a spectrum of initial responses to AI integration, ranging from enthusiasm to apprehension, emphasizing the need for comprehensive professional development and robust support systems. Educators anticipate significant shifts in their pedagogical roles, foreseeing AI as a facilitator of personalized learning but also expressing concerns about its potential to marginalize traditional teaching practices. Student reactions were generally positive, though mixed, highlighting the need for adaptive AI implementation strategies. Concerns about ethical implications and educational equity were prominent, underscoring the necessity of a balanced, ethical approach to AI deployment. The study contributes to the emerging body of literature on AI in education and offers insights for policymakers, curriculum developers, and educational technologists on effectively harnessing AI's potential while addressing its challenges. It calls for ongoing dialogue, professional development, and ethical considerations as AI becomes more integrated into educational systems, ensuring it serves as a supportive component within the pedagogical framework.

Refugees and asylum seekers in informal and precarious jobs: early labour market insertion from the perspectives of professionals and volunteers

PurposeThis article aims to explore the engagement of refugees and asylum seekers (RAS) in informal and precarious jobs from a civil society actors' perspective. Despite a burgeoning literature on refugee integration and a focus on institutional integration programmes, little is known about the early insertion of RAS into informal and precarious employment as an alternative to subsidised integration programmes, when these are available.Design/methodology/approachThis article draws on rich qualitative data collected through in-depth interviews with social workers, volunteers and other professionals supporting migrants.FindingsData analysis shows that migrants' insertion in informal jobs and their rejection of integration programmes may be the result of people's need to access financial capital to cover actual and future needs. Although such an engagement may be criticised for hampering RAS’ integration, it can be seen as an important source of agency against insecurity surrounding one's legal status.Originality/valueThis article highlights the importance of legal status precarity in shaping informal workers' agency and perceptions of them, opening up a debate on the relevance of informal work in terms of long-term integration and future migration trajectories.