Penetration rate is one of the most critical parameters affecting the performance of TBM machines and it is complicated to predict due to uncertainty in excavating operations and geological parameters. In this paper, using Monte Carlo simulation, the penetration rate is predicted, and the sensitivity of the parameters affecting the penetration rate in the TBM machine is evaluated. For this purpose, a database containing in-situ rock properties, rock mass characteristics, and mechanical parameters related to TBM in the Queens Water transfer tunnel has been used. A mathematical model has been developed using principal component analysis to simulate. The results of evaluating the performance of the developed model showed that the model has acceptable performance (VAF = 84.4%, RMSE = 0.03, NSE = 0.82, and R² = 0.84) and can be used in the development of Monte Carlo simulations. The simulation results showed that during the excavating route, the probability of achieving a penetration rate higher than 2.4 m/h is 90%. Also, the results of the effect of effective parameters on the penetration rate showed that with increasing parameters such as brittleness index (The most effective with a correlation coefficient of 0.528), angle between weakness plane, and tunnel axis, cutter head power, and cutter head torque, the penetration rate increases. Conversely, increasing parameters such as distance between plane of weakness, specific energy, and thrust force (The lowest effect with a correlation coefficient of − 0.13) of the machine has a negative effect on the penetration rate.
Storm-flood-dominated deltas are sedimentary systems in which a complex interplay of hydrodynamic processes occurs during storms (e.g. tropical cyclones) due to the coeval action of continental and oceanic processes. This paper reports on a superbly exposed, 135.5 m thick stratigraphic succession of the Pleistocene Cholan Formation exposed along the Da'an River, Taiwan. The sedimentary succession comprises alternating mudstone and sandstone, is mostly fine-grained, and exhibits multiple event beds that record deposition during tropical cyclones and post-depositional deformation features produced during earthquakes. Detailed facies analyses reveal that deposition towards the base of the succession occurred in the palaeo-Taiwan Strait in storm-flood-dominated prodelta and delta-front environments passing upwards into delta-plain environments. Tropical cyclone beds are encountered throughout the subaqueous storm-flood delta successions, and are identified by (i) trough cross-stratified sandstone bedsets with erosive bases that contain both mud clasts and mudstone beds, (ii) sandstone with aggrading wave ripples and (iii) hummocky cross-stratified sandstone with rare gutter casts filled with coal fragments and shell remains. Tropical cyclone deposits are either top-down burrowed or capped by massive or laminated mudstone. Seismites are rare and are mainly recognised through soft-sediment deformation of beds; they do not show evidence of slope failure. Compared to storm-flood delta successions described elsewhere, the Cholan Formation shows significantly fewer oscillatory-generated sedimentary structures and gutter casts. This difference is attributed to the Cholan Formation being deposited in and along the margin of a strait characterised by strong shore-parallel currents and relatively small storm waves due to its position between Taiwan and mainland China. This study refines depositional process interpretations of the Cholan Formation, provides criteria for recognising storm-flood delta deposits in tectonically active straits with multiple sediment sources fed by steep drainages and short river catchments, and provides additional criteria for recognising tropical cyclone deposits in shallow-marine settings.
This paper evaluates the properties of fly ash (FA) and ground granulated blast furnace slag (GGBFS) based geopolymer mortar mixtures with waste glass sand (WGS) obtained by crushing glass bottles. A total of seven mixtures, including the partial substitution of river sand (RS) with WGS (0%, 15%, 30%, and 45%) with two alkali activator solution to binder (AAS/b) ratio groups (0.4 and 0.3), were designed. Sodium silicate (Na 2 SiO 3 ) and sodium hydroxide (NaOH) were used as the alkali activators. The experimental program evaluated compressive strength, hardened density, alkali-silica reaction (ASR), drying shrinkage, and thermal conductivity of geopolymer mortar mixtures. Test results indicated that the compressive strength of the geopolymer mortar increased with the addition of WGS for AAS/b = 0.4, but it had a negative effect for AAS/b = 0.3. The FA and GGBFS-based geopolymer mortar helps to reduce the ASR expansion of the mixture containing WGS. The drying shrinkage of the geopolymer mortar decreases with the increase of the WGS content. The increase of WGS decreases the thermal conductivity of geopolymer mortar in the case of mixtures with AAS/b = 0.4, but interestingly thermal conductivity value increases in the case of mixtures with AAS/b = 0.3. The findings of this study suggest that using WGS as partial RS substitution material in geopolymer mortar offers sufficient mechanical and thermal insulation properties without causing durability issues.
This paper investigates the potential of Ubuntu philosophy for decolonising Participatory Research (PR) in the Global South, addressing power imbalances and research process challenges. Despite PR's focus on community involvement, it can perpetuate practices contradicting its principles , hence the rise of 'decolonising research' for fair, respectful researcher-community relationships and meaningful community knowledge. The central question is, 'How can Ubuntu serve as a tool for decolonising PR in the Global South?' Drawing from decolonisation, PR, and Ubuntu literature, we offer a novel perspective on applying Ubuntu in PR. The study demonstrates how Ubuntu promotes social change and justice, challenges Western knowledge universality, and empowers marginalised Global South communities via democratic, participatory platforms. We provide theoretical insights and practical suggestions for PR stakeholders, asserting that Ubuntu adoption can foster equitable, inclusive practices benefiting communities. The paper also invites further examination of indigenous philosophies in decolonising research, enriching knowledge production in the Global South and globally marginalised communities.
Leader self-serving behavior has been associated with a range of adverse outcomes in the workplace. However, much remains to be explored about why and when such leader behavior emerges in organizations. This research develops and tests a theoretical framework that delineates the emotional and cognitive states that give rise to leader self-serving behavior. Specifically, we draw on uncertainty management theory to theorize that job insecurity heightens leaders' anxiety and self-serving cognitions that subsequently trigger leader self-serving behavior. We further argue that the overall justice of an organization effectively mitigates the indirect relationship between a leader's sense of job insecurity and leader self-serving behavior via leader anxiety and self-serving cognitions. Results from a three-wave field study involving 481 leader-follower dyads provide support for our hypothesized model. We discuss the implications of our findings for leadership theory and practice. K E Y W O R D S anxiety, leader job insecurity, leader self-serving behavior, overall justice, self-serving cognitions
Wax/paraffin deposition in production wells and oil pipelines is a major challenge for oil production. Extensive research has been conducted to improve understanding of this process. This paper presents a review of experimental work carried out with flow loops. Previous research investigated paraffin deposition process under the influences of temperature, flow rate/velocity, shear stress, water fraction, gas phase, pipe material, asphaltene concentration, and chemical inhibitors. Test results reveal that temperature and shear stress have significant impacts on wax deposition. Limited research has been conducted on wax deposition under multiphase flow. Even though more than 20 years of efforts have been spent on wax deposition studies, unfortunately we have not fully understood this phenomenon.
Metal-doped carbon dots have attracted considerable attention in nanomedicine over the last decade owing to their high biocompatibility and great potential for bioimaging, photothermal therapy, and photodynamic therapy. In this study, we prepared, and for the first time, examined terbium-doped CDs (Tb-CDs) as a novel contrast agent for computed tomography. A detailed physicochemical analysis revealed that the prepared Tb-CDs have small sizes (∼2-3 nm), contain relatively high terbium concentration (∼13.3 wt%), and exhibit excellent aqueous colloidal stability. Furthermore, preliminary cell viability and CT measurements suggested that Tb-CDs exhibit negligible cytotoxicity toward L-929 cells and demonstrate high X-ray absorption performance (∼48.2 ± 3.9 HU L g −1). Based on these findings, the prepared Tb-CDs could serve as a promising contrast agent for efficient X-ray attenuation.
Background: Although recommended for all member states of World Health Organization, there is no national human papillomavirus vaccination program in Kazakhstan. Furthermore, there are no studies in Kazakhstan that evaluate the mothers' perception of human papillomavirus vaccines. Objectives: This study aims to assess the knowledge and attitudes toward human papillomavirus vaccination among mothers in Kazakhstan and the factors associated with their attitudes. Design: A cross-sectional study was performed during the period of December 2021-February 2022. The STROBE guideline for cross-sectional studies was applied. Methods: Paper-based structured questionnaires were filled out by 191 mothers, 141 of whom had daughters. The attitude score was assessed as per the Likert-type scale. The Chi-square and Fisher's exact tests, with a significance value of < 0.05 were used to analyze the relationships between the characteristics of mothers and their attitude scores. Results: The following factors were significantly associated with mothers' attitudes toward human papillomavirus vaccination: a place of residence, family income, number of children, and refusal of vaccination for themselves (p < 0.005). Of all participants, only 45% of all mothers, 41% of mothers with a female, and 46% of mothers with male children had positive attitudes toward human papillomavirus vaccination. The child's gender was not a significant determinant. Overall, the level of knowledge about human papillomavirus vaccination was found to be low. The median total score is 0 out of 12 for women who have negative and neutral attitudes toward human papillomavirus vaccines. Among women who have positive attitudes toward HPV vaccines, the median score is around 3 points. Conclusion: Before the implementation of the human papillomavirus vaccination program into the Kazakhstani national vaccination calendar, comprehensive and adequate information and education campaigns are required on the national level for parents and the population in general.
Lattice structures have a great potential in the fields like aerospace and biomedical, due to their outstanding properties like high strength, low mass, and good energy absorption capacity. With the development of the Additive Manufacturing technologies, there was an increasing attention towards these structures. The compressive behavior of the pilar octahedral lattice structure, which has the high strength to weight ratio was analyzed in this work. Lattice structures with three strut diameters of 1.5, 1.75, and 2 mm were built using Fused Filament Fabrication from Tough Polylactic Acid (PLA) plastic. Quasi-static compression tests were performed and two finite element models using beam elements with and without nodal beam diameter correction were proposed. It was found that as the diameter of the strut increases strength and elastic moduli are increased as well, while specific mechanical properties almost do not change. It was also confirmed from numerical and experimental results that lattice structure fails by forming a diagonal shear band. The relative error of the simulation without nodal correction in predicting the strength of the lattice with a 1.5 mm strut diameter was 1.58%. However, due to the inability of the beam element to model the behavior at the nodes properly its accuracy decreases for larger diameters. By modifying the model and using a nodal beam diameter correction, it has been possible to achieve a relative error of 0.58% and 12.15% for strut diameters of 1.75 and 2 mm respectively.
Among many kinds of electrolytes, Li1.3Al0.3Ti1.7(PO4)3 (LATP) ceramic electrolyte has a few focal points such as relatively low price, excellent resistance to air and moisture, high ionic conductivity, and environmental safety. Besides, LATP has a disadvantage in that it exposes batteries to degradation due to the interfacial layer formed after it touches metallic lithium because of the titanium reduction reaction. Herein, we report our results on the strategy of anion doping in LATP structures by Si (LATSP). The LATSP samples with various Si content were synthesized by a simple molten flux method at 800 °C with a pure phase. The structure, morphology, and ion-transport properties were analyzed. It was demonstrated that increasing Si doping content has significant positive effects on electrolyte conductivity.
The paper develops the concept of penal spectrality—a sense of the presence of those who endured past penal suffering within environments and among objects related to the practice of punishment. The residents of Ukhta, a Gulag town in Northern Russia, engage uncomfortably with penal spectrality and employ two forms of distancing—pragmatic and cultural—to deal with its melancholic affects. Pragmatically, residents repurpose and reincorporate the things of the penal past into the social order, finding a use-value in them for the present day. Culturally, residents engage in the museumification and commodification of Gulag things. The paper advances two directions for research in ghost criminology. First, we show how uneasy spectral feelings are not passively observed but actively negotiated. Second, in this interaction, we show the immediacy of engaged practical interaction with material objects that points to modes of encountering and misrecognizing penal suffering beyond cultural commodification and penal spectatorship.
We present an exactly soluble electron trajectory that permits an analysis of the soft (deep infrared) radiation emitted, the existence of which has been experimentally observed during beta decay via lowest order inner bremsstrahlung. Our treatment also predicts the time evolution and temperature of the emission, and possibly the spectrum, by analogy with the closely related phenomenon of the dynamic Casimir effect.
In his article, Grossmann argues that, in the context of human cooperative caregiving, heightened fearfulness in children and human sensitivity to fear in others are adaptive traits. I offer and briefly defend a rival hypothesis: Heightened fearfulness among infants and young children is a maladaptive trait that did not get deselected in the process of evolution because human sensitivity to fear in others mitigates its disadvantageous effects to a sufficient extent.
The emergence of the crisis in Sudan has led to an overstretched healthcare system therein, which has negatively impacted the public health system of the nation. The WHO has noted the closure of roughly sixteen hospitals since the start of the conflicts due to staff safety concerns as well as a shortage of hospital supplies, consumables, and medication. Due to ongoing conflicts and persistent political instability, Sudan receives very little funding from donor organizations to maintain its healthcare system, which worsens the nation’s general public health architecture. Thus, amidst the ongoing crisis recent floods in the country can further pose serious challenges like disease outbreaks, starvation, infectious diseases, deteriorating health infrastructure, and mental health issues. To successfully reduce the severity of negative impacts on public health, the crisis must be ceased and facilities reopened. A well-structured disease surveillance system for infectious diseases should be established, pregnant women and children under the age of five should be treated for free, and mental health awareness and examination should be prioritized. The global community must act expeditiously to mitigate the devastating effects of this crisis.
This study provides an overview of research findings on long-term effects on healthcare workers mental health and factors associated with positive or negative changes. Medline and PubMed databases were searched for observational longitudinal studies and 18 papers were included in the review (PROSPERO: CRD42021260307). 12 articles indicated negative changes over time and six studies revealed a positive trend in a variety of mental health outcomes (anxiety, depression, insomnia, and others). Female sex, younger age, nursing occupation, frontline work, longer working hours and concerns about contracting COVID-19 were identified to be associated with negative changes. Conversely, a supportive environment, access to psychological resources, provision of sufficient personal protective equipment and availability of COVID-19 tests were linked to positive changes. Therefore, our findings can assist governmental and institutional authorities with effective interventions to improve psychological care for healthcare workers.
The low viscosity of soundless cracking demolition agent (SCDA) slurries makes them difficult to use on rock and concrete breakage in horizontal and up holes, or wet holes. In this paper, self-swelling tablet cartridges are developed by use of additives including adhesive, wetting agent, water absorbent, and activator to SCDA powder through newly developed production technologies. The dosages of adhesive and wetting agent were optimized in the process of powder granulation. Their optimal addition amounts are 3.17% and 11.81%. The self-swelling tablet (SST) experiments and optimization tests show the hardness of SST improved with an increase in pressure and mold filling height. Subsequently, laboratory tests were conducted to determine the influence of the contents of water absorbent and activator on the SST water absorption, reaction temperature, and expansion pressure. The water absorption of SST was found to improve with an increase in water absorbent amount and particle size of the granules. The optimum dosage of the water absorbent is 10%. Based on the laboratory experiments, the optimum amount of additives in the SST is 5% for its best performance. The production of SST cartridges is in a safer and healthier environment compared to SCDA powder cartridges, and its production can be automated to reduce labour cost. Finally, the introduction of SST cartridges expands the scope of application of the SCDA to up holes, horizonal holes, and wet holes.
In this study, UVA and goethite activated persulfate oxidation was applied to treat a synthetic (SLL) and a real landfill leachate (RLL) spiked with sulfamethoxazole (SMX). Initially, SLL was used to find the optimum landfill leachate (LL) treatment conditions in terms of total organic carbon (TOC) and SMX removal. The screening experiments were conducted using a two-level, four-factor Plackett-Burman design (PBD) to investigate the effects of UVA irradiation, time, concentrations of persulfate (PS) and goethite, on the removal of TOC and SMX. Dark experiments (PS/Goethite) yielded only a 2% TOC removal. Therefore, further experiments were conducted under UVA (365 nm) using a three-factor Box-Behnken design (BBD) in conjunction with response surface methodology (RSM). Analysis of variance (ANOVA) indicated high regression coefficients for the BBD-RSM model in the case of TOC removal (R2 = 0.9755, adjusted R2 = 0.9314 and predicted R2 = 0.7956). In the case of SLL, RSM predicted an 84.4% TOC removal at the reaction time of 5.33 h, PS concentration of 477.4 mM, and goethite dosage of 755 mg/L under UVA. Experimentally, an 81.8% TOC removal and 100% removal of SMX were obtained under these conditions. Finally, the obtained optimum conditions were recalculated using RLL from the local municipal solid waste landfill, and 87% TOC and 100% SMX removals were obtained for PS concentration of 419.3 mM and goethite dosage of 663 mg/L after 4.68 h under UVA irradiation. Air stripping of RLL at pH 11 was complementarily applied to completely remove ammonia nitrogen after 3 hours. The results demonstrated the efficiency of the UVA/PS/Goethite system for the removal of organic matter from the LL for the first time.
Workfare programs (WPs) in low- and middle-income countries have become a primary instrument to fight poverty associated with temporary economic shocks or to create a pathway out of chronic poverty. In this paper, we examine the design and implementation of a WP in Kazakhstan. We do so by executing a cost effectiveness analysis (CEA) and performing a case study analysis which investigates how the implementation process unfolded and what factors shaped it most. We find that the high cost per unit of current benefit of Kazakhstan's WP is, in part, the result of benefit 'leakage' to the non-poor, high levels of informal labor, and means-testing applicants. Furthermore, overly bureaucrat requirements of official residency and household asset documents, poor staff training because of high staff turnover, staff not following standardized procedures because of low wages and corruption, and central government KPIs resulted in "creaming" of the best applicants and improper blending with other active labor market policies. Our findings provide important lessons, such as (1) formal restrictions on eligibility lead to expensive means-testing of applicants and (2) official residency and household asset documents lead to "creaming" of the best applicants.
The growing environmental and energy crises have prompted researchers to seek new solutions, including large-scale photocatalytic environmental remediation and the production of solar hydrogen using photocatalytic materials. To achieve this goal, scientists have developed numerous photocatalysts with high efficiency and stability. However, the large-scale application of photocatalytic systems under real-world conditions is still limited. These limitations arise at every step, including the large-scale synthesis and deposition of photocatalyst particles on a solid support, and the development of an optimal design with high mass transfer and efficient photon absorption. The purpose of this article is to provide a detailed description of the primary challenges and potential solutions encountered in scaling up photocatalytic systems for use in large-scale water and air purification and solar hydrogen production. Additionally, based on a review of current pilot developments, we draw conclusions and make comparisons regarding the main operating parameters that affect performance, as well as propose strategies for future research.
Institution pages aggregate content on ResearchGate related to an institution. The members listed on this page have self-identified as being affiliated with this institution. Publications listed on this page were identified by our algorithms as relating to this institution. This page was not created or approved by the institution. If you represent an institution and have questions about these pages or wish to report inaccurate content, you can contact us here.
53 Qabanbay Batyr Avenue, 010000, Astana, Aqmola, Kazakhstan
Head of institution