bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of COVID-19 Pandemic on Dietary Habits and Sleep Quality Applying the Pittsburgh Sleep Quality Index in Adult Saudi Population: A Cross-Sectional Study
Authors: Alharbi Hend F. , Barakat Hassan
Published: September 2022

The study aimed to evaluate the possible correlations between sleep quality and dietary habits in a population of Saudi during the COVID-19 pandemic. Exactly 444 adults completed a web-based cross-sectional study using an electronic questionnaire. Results indicate a significant difference between body mass index (BMI) and bad sleep quality. Smoking is linked to bad sleep quality. Both genders affected by coronavirus had a substantially bad quality compared to non-affected. An association between the degree of craving for sugar and bad sleep quality was found. In addition, there was a statistical difference between males and females who crave sugar very often in bad sleep quality. The result of sleep latency in males was 35.83%, who suffered from a severe sleep disorder, while 41.18% were female. The sleep duration was 65.00%, and 53.90% of males and females slept between 6 and 7 h per day. Sleep efficiency, measured according to the Pittsburgh questionnaire protocol, was measured in percentages, where a value of less than 65.00% is considered the lowest sleep efficiency. Females had a lower sleep efficiency of 25.49% compared to males (13.33%). These differences were statistically significant (p = 0.03). In conclusion, quality and sleep duration were impaired during the COVID-19 pandemic, and the observed changes were associated with diet.
Psychosocial Determinants of Loneliness in the Era of the COVID-19 Pandemic—Cross-Sectional Study
Authors: Sierakowska Matylda , Doroszkiewicz Halina
Published: September 2022

Background: The COVID-19 pandemic affected the mental health and social behavior of people around the world. Due to epidemiological restrictions, the period of forced isolation contributed to the feeling of loneliness. The aim of the research is to identify factors and conditions associated to the feeling of loneliness in the era of the COVID-19 pandemic. Methods: The survey was conducted among 262 people from the north-eastern Polish area, using an online survey. The diagnostic survey method was used, using the De Jong Gierveld Loneliness Measurement Scale, the Generalized Self-Efficacy Scale (GSES), the WHOQoL-Bref questionnaire. Results: A statistically significant relationship was observed between the feeling of loneliness and areas of quality of life, especially psychological and social, generalized self-efficacy and marital status and way of living (p < 0.05). Higher levels of stress, social distancing, restrictions at work, health status were significantly correlated with an increase in loneliness. Remote work was associated with a lower assessment of the quality of life in the psychological field (p < 0.05). Conclusions: Higher levels of loneliness were significantly more likely to affect people living alone and not in a relationship. Higher levels of loneliness were significantly associated with lower quality of life in the social and psychological domains, lower levels of self-efficacy, and remote work.
Dual-Task-Based Music Therapy to Improve Executive Functioning of Elderly Patients with Early Stage Alzheimer’s Disease: A Multiple Case Study
Authors: Kim Soo Ji , Park Jin-Kyoung , Yeo Myung Sun
Published: September 2022

Deficits in executive functioning are a common feature of Alzheimer’s disease (AD) and result from impairment in the central executive system. As a result, elderly patients with early stage AD may require interventions that are more cognitively intense than traditional interventions. To address this need, in this multiple case study, we explored a dual-task-based music therapy intervention that involved drum playing and singing designed to induce attentional and motor controls. Three octogenarians diagnosed with early stage AD participated in 12 dual-task-based music therapy sessions over 6 weeks. Measures of executive functioning and the performance of a bimanual drum tapping task were evaluated before and after the intervention. Improvements in executive functioning were observed for participants A and C. After the intervention, reduced mean synchronization errors were found for the simultaneous tapping condition for all three participants. Although there was variability in the functional changes between participants, it is noteworthy that positive improvements in the elderly patients with early stage AD were obtained following dual-task-based music therapy. The results suggest that music therapy integrated into the dual-task paradigm can be an effective way to address degenerative cognitive deficits among elderly patients with early stage AD.
How Portuguese Health Entities Used Social Media to Face the Public Health Emergency during COVID-19 Disease
Authors: Azevedo Daniela , Plácido Ana Isabel , Herdeiro Maria Teresa , Roque Fátima , Roque Vítor
Published: September 2022

Background: During the COVID-19 pandemic, social media became an important and easily accessible source of information to keep the population informed. In this study, we explored how Portuguese health entities used social media during the public health emergency caused by COVID-19 disease. Methods: A retrospective study on Portuguese public health entities’ communication with the public using social media platforms was performed. Data were retrieved from Facebook, Instagram, and Twitter. All retrieved posts were analyzed, and the engagement of the public was calculated. A thematic analysis of all COVID-19-related posts was conducted. Results: The analysis of each social media platform revealed that during the COVID-19 pandemic, health entities reinforced their presence on social media platforms. The most published posts were related to “epidemiological context” and “encouragement to take actions” to avoid the spread of COVID-19. High engagement frames were not associated with the most frequently published posts. Conclusions: Although health entities have reinforced their presence on social media platforms, they do not take full advantage of these platforms to improve health literacy.
Context Matters—Child Growth within a Constrained Socio-Economic Environment
Authors: Nyati Lukhanyo H. , Patel Leila , Haffejee Sadiyya , Sello Matshidiso , Mbowa Sonia , Sani Tania , Norris Shane A.
Published: September 2022

Communities in major cities in developing countries may experience economic vulnerability, which has detrimental consequences for maternal and child health. This study investigated individual-, household-, and community-level factors associated with child growth and resilience of early-grade learners aged 6 to 8 years. Demographic characteristics, depression scale, child wellbeing, and anthropometric measurements were collected on a sample of 162 caregiver–child pairs (children 46% female) who receive the child support grant (cash transfer programme) from five low-income urban communities in the City of Johannesburg, South Africa. Height and weight were converted to z-scores using the WHO Anthroplus software. Multiple linear regression was used to assess factors associated with child health outcomes and multi-level regression to account for community-level factors. Higher income vulnerability was associated with lower weight- and height-for-age z-scores (WAZ and HAZ). Not completing secondary schooling and higher household size were associated with lower HAZ but higher BAZ. Child male sex and caregiver with depression were associated with lower child resilience. Caregiver’s level of schooling and household size remained independent predictors of child growth, while the caregiver’s mental health status independently predicted child resilience. Thus, notwithstanding systemic constraints, there may be modifiable drivers that can help in developing targeted intervention.
Effects of Cardiovascular Disease Risk Factors, Musculoskeletal Health, and Physical Fitness on Occupational Performance in Firefighters—A Systematic Review and Meta-Analysis
Authors: Ras Jaron , Kengne Andre P. , Smith Denise L. , Soteriades Elpidoforos S. , November Rucia V. , Leach Lloyd
Published: September 2022

Background: Firefighting is a strenuous occupation, which necessitates that firefighters stay in good physical condition and maintain adequate cardiovascular and musculoskeletal fitness to perform their duties with minimal health and safety risks. The aim of this review is to determine the effects of cardiovascular disease risk factors, musculoskeletal health, and physical fitness on the occupational performance of firefighters. Methods: PubMed/Medline, SCOPUS, Web of Science, EBSCOHost, and ScienceDirect were searched without time-restriction. The appraisal tool for cross-sectional studies and the Critical Appraisal Skills Programme toolkit were used to conduct the methodological assessment. Data were analyzed using Review Manager 5.3, and MedCalc® statistical software. Results: Age had a moderate effect on occupational performance (Z = 5.15, p < 0.001), whereas gender had a large effect size on occupational performance (Z = 4.24, p < 0.001). A significant moderate negative correlation was found between cardiorespiratory fitness and occupational performance (R = −0.584, p < 0.001). Significant low negative correlations were found between upper body endurance (R = −0.344, p < 0.001), abdominal endurance (R = −0.308, p < 0.001), grip strength (R = −0.421, p < 0.001), upper body strength (R = −0.318, p < 0.001), and lower body strength (R = −0.216, p = 0.020) and occupational performance. Conclusions: Aged firefighters with poor body composition and lower levels of physical fitness performed worse on all occupational performance tasks.
The Influence of Framing Plant-Based Products in Terms of Their Health vs. Environmental Benefits: Interactions with Individual Wellbeing
Authors: Isham Amy , Geusen Judith , Gatersleben Birgitta
Published: September 2022

Significant reductions in the consumption of meat and dairy products are required to limit environmental damage and meet climate targets. However, individuals choosing to adopt plant-based diets still form a minority. Whilst different types of message framings have been suggested to be a potential means of encouraging the uptake of plant-based diets, recent findings have often failed to document any differences in people’s willingness to reduce their consumption of animal products based on whether messages emphasize the health or environmental benefits of plant-based diets. This research examined whether individual wellbeing might interact with health versus environmental message frames to determine people’s liking and willingness to pay for plant-based products. Across two experiments with a university (Study 1) and a non-student, adult sample (Study 2), participants were exposed to different hypothetical labels for plant-based foods and asked to rate their liking and willingness to pay for each. In line with existing findings, results demonstrated a trend whereby showing health (versus environmental) information on food labels did not in itself influence participants perceptions of the food products. Higher levels of positive wellbeing were associated with greater liking and willingness to pay for the plant-based foods (B values ranging from 0.04 to 0.45). Further, there was an interaction effect whereby levels of negative affect were differentially linked to liking and willingness to pay across the health and environmental framing conditions (B values ranging from 0.03 to 0.38). In particular, negative affect appears to have a greater negative impact on the product liking and willingness to pay when environmental label framings are used. This effect was most pronounced for the product liking dependent variable (B = −0.29 in the environmental framing condition). This research therefore extends understandings of the more specific instances in which message framings can impact perceptions of plant-based foods. The implications of the findings for understanding how best to promote uptake of plant-based diets are discussed.
Forty-Year Biomonitoring of Environmental Contaminants in Russian Arctic: Progress, Gaps and Perspectives
Authors: Dudarev Alexey A. , Odland Jon Oeyvind
Published: September 2022

This article presents a comprehensive survey of the studies on the biomonitoring of persistent organic pollutants (POPs) and metals in biota and human tissues on the territory of the Russian Arctic. It is concluded that a relatively small number of studies were carried out during the last 40 years; for several Russian Arctic regions there is no data up to date, and for some regions the data are scarce, with most of the studies carried out in 1990s, followed by the large-scale GEF/AMAP/RAIPON project of 2001–2004 covering four regions. After that, single projects have been implemented in a few regions. Only the Nenets okrug and the Chukotka okrug (and hardly the Murmansk oblast) can be attributed as the regions where the biomonitoring of contaminants was carried out during last decades on several occasions, and for which the content of POPs and metals in biota and the human organism was assessed in 12–15-year dynamic trends (at least “at three points”). For the rest of the Russian Arctic territories, only fragmentary “cross-sections” of biomonitoring data is available, mainly obtained in the 1990s or early 2000s, which do not allow judging either the dynamics of the processes or the current state of affairs. The overwhelming majority of the studies in the Russian Arctic (more than 90%) were carried out within the framework of international projects, i.e., with cofinancing, assistance and contribution (including laboratory analyses) from the foreign colleagues and partners. The shortcomings of the Russian system of biomonitoring, including the weakness of the laboratory and research base, are considered. Perspectives of the Russian Arctic biomonitoring are discussed in detail, with the proposal of the elaboration of the national Russian Arctic Contaminants Program (RACP).
How Does Topography Affect the Value of Ecosystem Services? An Empirical Study from the Qihe Watershed
Authors: Li Li , Li Yonghui , Yang Lan , Liang Ying , Zhao Wenliang , Chen Guanyu
Published: September 2022

Topographic position indices (TPIs) measure essential impacts on ecosystem service supply capacity. The identification of changes in ecosystem services and value metrics under varying TPIs has become a topical subject of global change research. Multidimensional changes in spatiotemporal and geographical aspects of ecosystem service values (ESVs) are assessed in this article using land cover/use data from 2000–2015. Effects of land-use/cover changes and topographic indices on ESVs are explored using the Chinese terrestrial unit area ecosystem service value equivalence table combined with topographic factors. A sensitivity index is introduced to quantify the robustness of total ESV to land-use/cover and topographic indices. The results show that: (1) The total ESV in the Qihe watershed declined with a change in land-use/cover during the period 2000–2015. The maximum ESV was CNY 1.984 billion in 2005 and the minimum was CNY 1.940 billion in 2010; (2) The response of ESV to land/use cover varied greatly across TPIs, with the most significant change in ESV occurring in the 0.6–0.8 TPI range and the greatest change in a single ecosystem service occurred in water areas; (3) The sensitivity indices of ESVs are all less than 1. The sensitivity indices of unused land and water tended to zero. Woodland sensitivity indices were the highest at 0.53, followed by those of arable land and grassland, owing to the large proportion of arable land and grassland areas in the overall area of land-use categories.
A Realist Review of How Community-Based Drug Checking Services Could Be Designed and Implemented to Promote Engagement of People Who Use Drugs
Authors: Masterton Wendy , Falzon Danilo , Burton Gillian , Carver Hannah , Wallace Bruce , Aston Elizabeth V. , Sumnall Harry , Measham Fiona , Gittins Rosalind , Craik Vicki , Schofield Joe , Little Simon , Parkes Tessa
Published: September 2022

With rising numbers of drug-related deaths in the UK and globally, exploration of interventions that seek to reduce drug-related harm is essential. Drug checking services (DCS) allow people to submit drug samples for chemical analysis and receive feedback about the sample, as well as harm reduction advice. The use of DCS is often linked to festival and/or nightlife settings and to so-called ‘recreational’ drug use, but research has also shown the potential of community-based DCS as an intervention serving more varied demographics of people who use drugs, including more marginalised individuals and those experiencing drug dependence. Whilst there is a growing evidence base on the effectiveness of drug checking as a harm reduction intervention, there is still limited evidence of the underlying mechanisms and processes within DCS which may aid implementation and subsequent engagement of people who use drugs. This presents a challenge to understanding why engagement differs across types of DCS, and how best to develop and deliver services across different contexts and for different populations. To explore the contexts and mechanisms which impact engagement in community-based DCS, a realist review was undertaken to synthesise the international evidence for the delivery and implementation of DCS. There were 133 sources included in the review. From these sources the underlying contexts, mechanisms, and outcomes relating to DCS implementation and engagement were developed and refined into seven programme theories. The findings of this review are theoretically novel and hold practical relevance for the design of DCS, with implications for optimisation, tailoring, and implementing services to reach individuals in different settings.
A Review of the Impact That Healthcare Risk Waste Treatment Technologies Have on the Environment
Authors: Zikhathile Thobile , Atagana Harrison , Bwapwa Joseph , Sawtell David
Published: September 2022

Health-Care Risk Waste (HCRW) treatment protects the environment and lives. HCRW is waste from patient diagnostics, immunization, surgery, and therapy. HCRW must be treated before disposal since it pollutes, spreads illnesses, and causes harm. However, waste treatment increases the healthcare sector’s carbon footprint, making the healthcare sector a major contributor to anthropogenic climate change. This is because treating HCRW pollutes the environment and requires a lot of energy. Treating HCRW is crucial, but its risks are not well-studied. Unintentionally, treating HCRW leads to climate change. Due to frequent climate-related disasters, present climate-change mitigation strategies are insufficient. All sectors, including healthcare, must act to mitigate and prevent future harms. Healthcare can reduce its carbon footprint to help the environment. All contributing elements must be investigated because healthcare facilities contribute to climate change. We start by evaluating the environmental impact of different HCRW treatment technologies and suggesting strategies to make treatments more sustainable, cost-effective, and reliable to lower the carbon footprint.
Improving COVID-19 Vaccine Uptake among Black Populations: A Systematic Review of Strategies
Authors: Adeagbo Morolake , Olukotun Mary , Musa Salwa , Alaazi Dominic , Allen Upton , Renzaho Andre M. N. , Sekyi-Otu Ato , Salami Bukola
Published: September 2022

Given the growing body of evidence on COVID-19 vaccine hesitancy among Black populations, the aim of this systematic review was to identify the interventions and strategies used to improve COVID-19 vaccine confidence and uptake among Black populations globally. To identify relevant studies, we conducted a systematic review of the literature based on a systematic search of 10 electronic databases: MEDLINE, Embase, PsycINFO, CINAHL, Scopus, Cochrane Library, Web of Science, Sociological Abstracts, Dissertations and Theses Global, and SocINDEX. We screened a total of 1728 records and included 14 peer-reviewed interventional studies that were conducted to address COVID-19 vaccine hesitancy among Black populations. A critical appraisal of the included studies was performed using the Newcastle-Ottawa Quality Assessment Scale. The intervention strategies for increasing COVID-19 vaccine uptake were synthesized into three major categories: communication and information-based interventions, mandate-based interventions, and incentive-based interventions. Interventions that incorporated communication, community engagement, and culturally inclusive resources significantly improved vaccine uptake among Black populations, while incentive- and mandate-based interventions had less impact. Overall, this systematic review revealed that consideration of the sociocultural, historical, and political contexts of Black populations is important, but tailored interventions that integrate culture-affirming strategies are more likely to decrease COVID-19 vaccine hesitancy and increase uptake among Black populations.
PTSD and PTG in French and American Firefighters: A Comparative Study
Authors: Henson Charlotte , Truchot Didier , Canevello Amy
Published: September 2022

Studies show that experiencing traumatic events can lead to positive psychological change, or posttraumatic growth (PTG). In the hope of promoting PTG, authors have been focusing on identifying the factors that may foster PTG. Despite these attempts, the literature shows inconsistencies, making it difficult to know which variables may be involved in the process of growth. Indeed, authors seem to disagree on the nature of the relationship between PTSD and PTG, time since the event, social support, intrusive rumination, and sociodemographics. Thus, this study aims to clarify these discrepancies, and verify whether the processes involved are the same across two different cultural groups, both of which are confronted with traumatic events regularly: 409 American firefighters, and 407 French firefighters. Results indicate that, in both samples, PTG is positively related to PTSD, subjective perceptions of the event, stress during the event, disruption of core-beliefs, and deliberate rumination; and unrelated to social support, core-self evaluations, and socio-demographic variables (age, gender, relationship status, etc.). However, time since the event and the number of years on the job only predicted PTG in the American sample, while colleague and emotional support only predicted PTG in the French sample. Additionally, American firefighters reported more growth, more social support, more positive self-perceptions, more intrusive rumination, and more neuroticism than French firefighters. These results suggest that the process of growth, as defined by Tedeschi and Calhoun, is relatively stable among firefighters, but that some differences do exist between cultural groups.
Synthesis of Novel α-Trifluoroanisole Derivatives Containing Phenylpyridine Moieties with Herbicidal Activity
Authors: Cai Zengfei , Cao Yangyang , Du Xiaohua
Published: September 2022

To find novel herbicidal compounds with high activity and broad spectrum, a series of phenylpyridine moiety-containing α-trifluoroanisole derivatives were designed, synthesized, and identified via nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS). Greenhouse-based herbicidal activity assays revealed that compound 7a exhibited > 80% inhibitory activity against Abutilon theophrasti, Amaranthus retroflexus, Eclipta prostrate, Digitaria sanguinalis, and Setaria viridis at a dose of 37.5 g a.i./hm2, which was better than fomesafen. Compound 7a further exhibited excellent herbicidal activity against Abutilon theophrasti and Amaranthus retroflexus in this greenhouse setting, with respective median effective dose (ED50) values of 13.32 and 5.48 g a.i./hm2, both of which were slightly superior to fomesafen (ED50 = 36.39, 10.09 g a.i./hm2). The respective half-maximal inhibitory concentration (IC50) for compound 7a and fomesafen when used to inhibit the Nicotiana tabacum protoporphyrinogen oxidase (NtPPO) enzyme, were 9.4 and 110.5 nM. The docking result of compound 7a indicated that the introduction of 3-chloro-5-trifluoromethylpyridine and the trifluoromethoxy group was beneficial to the formation of stable interactions between these compounds and NtPPO. This work demonstrated that compound 7a could be further optimized as a PPO herbicide candidate to control various weeds.
Cellular and Molecular Targets in Acute Ischemic Stroke
Authors: Kraft Peter , Schuhmann Michael K.
Published: September 2022

Despite the available treatment strategies, ischemic stroke (IS) is still a leading cause of death and disability worldwide [...]
Radiation Damage in Polyethylene Naphthalate Thin-Film Scintillators
Authors: Campajola Marcello , Di Capua Francesco , Casolaro Pierluigi , Sarnelli Ettore , Aloisio Alberto
Published: September 2022

This paper describes the scintillation features and the radiation damage in polyethylene naphthalate 100 µm-thick scintillators irradiated with an 11 MeV proton beam and with a 1 MeV electron beam at doses up to 15 and 85 Mrad, respectively. The scintillator emission spectrum, optical transmission, light yield loss, and scintillation pulse decay times were investigated before and after the irradiation. A deep blue emission spectrum peaked at 422 nm, and fast and slow scintillation decay time constants of the order of 1–2 ns and 25–30 nm, respectively, were measured. After irradiation, transmittance showed a loss of transparency for wavelengths between 380 and 420 nm, and a light yield reduction of ~40% was measured at the maximum dose of 85 Mrad.
Magnetic Zr-Based Metal-Organic Frameworks: A Highly Efficient Au (III) Trapper for Gold Recycling
Authors: Chang Ziyong , Gong Xiaosha , Zeng Liang , Wang Junlian , Zhu Yangge
Published: September 2022

In this work, the magnetic Zr-based MOF composites with excellent retrievability were prepared using Fe3O4@SiO2 as the core and UiO–66–NH2 as the shell. Fe3O4@SiO2 core could introduce mesopores and result in capillary condensation in MOF composites, which aggravated with the dosage of Fe3O4@SiO2. The as-synthesized MOF composites could be rapidly retrieved from aqueous solution via magnetic separation in 10 seconds. pH imposed an important effect on Au (III) adsorption by governing the ion exchange and electrostatic interaction between Au (III) anions and adsorbents, and the optimal adsorption happened at pH 7. The adsorption process fitted well with the pseudo-second order kinetics model and Langmuir adsorption model. The maximum adsorption capacity of Au (III) by FSUN–10 and FSUN–50 at 298 K were determined to be 611.18 mg∙g−1 and 463.85 mg∙g−1, respectively. Additionally, Au (III) uptakes increased with temperature. Beyond experiments, the adsorption mechanisms were thoroughly studied through systematic characterization, molecular dynamics simulation (MDS) and density functional theory (DFT) study. It was verified that Au (III) was adsorbed via coordination to hydroxyl and amino groups and was reduced to Au (I) and Au (0) by amino groups. The diffusion coefficient of Au (III) along UiO–66–NH2 was calculated to be 5.8 × 10−5 cm2∙s−1. Moreover, the magnetic Zr-based MOF composites exhibit great industrial value in gold recycling with high adsorption selectivity and good recyclability.
Kinetics of Magnesiothermic Reduction of Natural Quartz
Authors: Rasouli Azam , Tsoutsouva Maria , Safarian Jafar , Tranell Gabriella
Published: September 2022

In this work, the kinetics of natural quartz reduction by Mg to produce either Si or Mg2Si was studied through quantitative phase analysis. Reduction reaction experiments were performed at various temperatures, reaction times and Mg to SiO2 mole ratios of 2 and 4. Rietveld refinement of X-ray diffraction patterns was used to obtain phase distributions in the reacted samples. SEM and EPMA examinations were performed to evaluate the microstructural change during reduction. The results indicated that the reduction reaction rate was slower at a mole ratio of 2 than 4 at the same temperature, as illustrated by the total amount of Si formed (the percent of Si that is reduced to either Si or Mg2Si to total amount of Si) being 59% and 75%, respectively, after 240 min reaction time for mole ratios of 2 and 4. At the mole ratio of 4, the reaction rate was strongly dependent on the reaction temperature, where SiO2 was completely reduced after 20 min at 1273 K. At the lower temperatures of 1173 and 1073 K, total Si formed was 75% and 39%, respectively, after 240 min reaction time. The results of the current work show that Mg2Si can be produced through the magnesiothermic reduction of natural quartz with high yield. The obtained Mg2Si can be processed further to produce silane gas as a precursor to high purity Si. The combination of these two processes offers the potential for a more direct and low carbon method to produce Si with high purity.
Froth Flotation of Chalcopyrite/Pyrite Ore: A Critical Review
Authors: Castellón César I. , Toro Norman , Gálvez Edelmira , Robles Pedro , Leiva Williams H. , Jeldres Ricardo I.
Published: September 2022

In the present work an intense bibliographic search is developed, with updated information on the microscopic fundamentals that govern the behavior of flotation operations of chalcopyrite, the main copper mineral in nature. In particular, the effect caused by the presence of pyrite, a non-valuable mineral, but challenging for the operation due to its ability to capture a portion of collector and float, decreasing the quality of the concentrate, is addressed. This manuscript discusses the main chemical and physical mechanisms involved in the phenomena of reagent adsorption on the mineral surface, the impact of pH and type of alkalizing agent, and the effect of pyrite depressants, some already used in the industry and others under investigation. Modern collector reagents are also described, for which, although not yet implemented on an industrial scale, promising results have been obtained in the laboratory, including better copper recovery and selectivity, and even some green reagents present biodegradable properties that generate a better environmental perspective for mineral processing.
Experimental Investigation of Cohesion between UHPC and NSC Utilising Interface Protrusions
Authors: Horák Pavel , Pešková Šárka , Jogl Marcel , Sovják Radoslav , Vítek Petr
Published: September 2022

The interaction of ultrahigh-performance concrete (UHPC) and normal-strength concrete (NSC) is one of the main issues for strengthening conventional concrete structures or other applications where NSC and UHPC are interrelated. UHPC stands out for its strength and durability, while NSC is significantly inexpensive and easier to work with. Efficiently designed structures can exploit the advantages of both mixtures. At the interface of these materials in newly designed structures, the formwork can be modified at the interface to give the concrete surface sufficient roughness and thus cohesion as required. This improves both the tensile and shear strength of the contact resulting in the enhanced capacity of the composite structure. In this study, a button foil was inserted into the formwork for the UHPC and then a part of NSC was made. The shear strength of the interface without any stress component in the transverse direction was measured on small-scale samples. It was to justify the possibility of the use of this interface in real constructions such as beams and columns. The main objective of further research is to design a composite beam using a UHPC shell as formwork for NSC and protrusions at the interface. It is expected that the U-shaped shell made of the UHPC could significantly contribute to the load-bearing capacity of the resulting composite NSC–UHPC structure and also to its enhanced durability. In addition, if the NSC is enclosed in a shell of UHPC, it can be made from various secondary materials, therefore it can decrease cement consumption by more than 50%.
A Statistical Porosity Characterization Approach of Carbon-Fiber-Reinforced Polymer Material Using Optical Microscopy and Neural Network
Authors: Eliasson Sara , Karlsson Hagnell Mathilda , Wennhage Per , Barsoum Zuheir
Published: September 2022

The intensified pursuit for lightweight solutions in the commercial vehicle industry increases the demand for method development of more advanced lightweight materials such as Carbon-Fiber-Reinforced Composites (CFRP). The behavior of these anisotropic materials is challenging to understand and manufacturing defects could dramatically change the mechanical properties. Voids are one of the most common manufacturing defects; they can affect mechanical properties and work as initiation sites for damage. It is essential to know the micromechanical composition of the material to understand the material behavior. Void characterization is commonly conducted using optical microscopy, which is a reliable technique. In the current study, an approach based on optical microscopy, statistically characterizing a CFRP laminate with regard to porosity, is proposed. A neural network is implemented to efficiently segment micrographs and label the constituents: void, matrix, and fiber. A neural network minimizes the manual labor automating the process and shows great potential to be implemented in repetitive tasks in a design process to save time. The constituent fractions are determined and they show that constituent characterization can be performed with high accuracy for a very low number of training images. The extracted data are statistically analyzed. If significant differences are found, they can reveal and explain differences in the material behavior. The global and local void fraction show significant differences for the material used in this study and are good candidates to explain differences in material behavior.
Thermally Modified Palygorskite Usage as Adsorbent in Fixed-Bed Reactor for High Concentration NH4+-N Removal and Further Application as N—Fertilizer in Hydroponic Cultivation
Authors: Lazaratou Christina Vasiliki , Panagopoulos Stylianos Dimitrios , Vayenas Dimitrios V. , Panagiotaras Dionisios , Papoulis Dimitrios
Published: September 2022

Palygorskite sample (Pal) underwent thermal treatment at 400 °C (T-Pal) to be used as adsorbent for the removal of 200 mg NH4+-N/L from artificial solution. After thermal treatment, the sample was characterized via X-ray diffraction (XRD) and scanning electron microscopy (SEM). For NH4+-N removal, T-Pal was added as a bed matrix in fixed-bed reactor experiments and the effect of flow rate was determined. It was indicated that with the flow rate increase from 10 mL/min to 50 mL/min, fewer liters of the solution were purified, rendering a longer residual time of interactions, which is optimal for NH4+-N removal from T-Pal. The maximum removed amount was calculated at 978 mg NH4+-N (qtotal), suggesting T-Pal is a promising ammonium adsorbent. The data of kinetic experiments were applied to Clark, Yoon–Nelson, and Thomas kinetic models, with Clark having the best fit, highlighting a heterogenous adsorption. At the end of kinetic experiments, T-Pal applied in hydroponic cultivations and presented a sufficient release rate, which was found utilizable for saturated T-Pal usage as N fertilizer that satisfactory results were deemed concerning lettuces characteristics and growth.
Mechanical and Acoustic Emission Characteristics of Coal-like Rock Specimens under Static Direct Shear and Dynamic Normal Load
Authors: Guo Jun , Yu Luyang , Wen Zhijie , Feng Guorui , Bai Jinwen , Wen Xiaoze , Qi Tingye , Qian Ruipeng , Zhu Linjun , Guo Xingchen , Mi Xincheng
Published: September 2022

In underground engineering, shear failure is a common failure type in coal-rock mass under medium and low strain-rate disturbance loads. Analyzing the shear failure mechanical properties of coal-rock mass under dynamic normal load is significant. In order to reveal the influence of disturbance load on the shear mechanical properties of coal rock, a dynamic and static load coupling electro-hydraulic servo testing machine was used to conduct the shear tests of coal-like rock materials under dynamic and constant normal load. The amplitude of dynamic load is 10 kN and the frequency is 5 Hz. The damage process of the specimens was detected by the acoustic emission (AE) detection system. The results imply that the shear failure process of coal-like rock materials under constant normal load can be divided into four stages. The normal disturbance decreased the shear strength of the specimens and increased the shear modulus of the specimens. With the increase in normal load, the influence of disturbance on the shear strength of the specimen decreased. By analyzing the AE parameters, it was found that the dynamic load made the internal damage of the specimen more severe during the shear failure process. The damage variable was calculated by AE cumulative energy, and the damage evolution was divided into three stages. The shear failure mechanism of the specimen was judged by RA (rise time/amplitude) and AF (average frequency). It was found that from the elastic deformation stage to the unstable development fracture stage, the proportion of shear fracture increased. When the dynamic normal load was 10 kN and 30 kN, the fracture was mainly shear fracture; When the dynamic normal load was 50 kN, the fracture was mainly tensile or mixed fracture. The dynamic normal load affects the shear strength and failure mechanism. Therefore, the influence of disturbance load on coal-rock mass strength cannot be ignored in underground engineering.
Sintering Analysis of Porous Ti/xTa Alloys Fabricated from Elemental Powders
Authors: Macias Rogelio , Garnica-Gonzalez Pedro , Olmos Luis , Jimenez Omar , Chavez Jorge , Vazquez Octavio , Alvarado-Hernandez Francisco , Arteaga Dante
Published: September 2022

The present work is focused on developing Ti-xTa porous alloys processed by the space holder method and solid-state sintering. The volume fraction of Ta ranged between 20 and 30 wt.%. The sintering kinetics was evaluated by dilatometry tests. Sintered materials were characterized by SEM, XRD and computed tomography. Porosity features and permeability were determined from 3D images, and their mechanical properties were evaluated from microhardness and compression tests. The sintering behavior and the final microstructure are driven by the Ta diffusion into the Ti, slowing down the densification and modifying the transition temperature of α-to-β. Due to β-stabilization, martensite α′ was obtained after sintering. Mechanical properties are reduced because of the β-stabilization and pore addition, being predominantly the pore effect. Permeability depended on the pore characteristics, finding values close to the human bones. It was concluded that powder metallurgy generates highly TixTa alloys with a combination of α, β and α′ Ti phases as well as remaining Ta particles that are beneficial to improve the biocompatibility and osseointegration of such materials. Being the Ti25Ta40salt alloy the most suitable for orthopedic implants because of its characteristics and properties.
Investigation of the Microstructure, Optical, Electrical and Nanomechanical Properties of ZnOx Thin Films Deposited by Magnetron Sputtering
Authors: Mazur Michał , Obstarczyk Agata , Posadowski Witold , Domaradzki Jarosław , Kiełczawa Szymon , Wiatrowski Artur , Wojcieszak Damian , Kalisz Małgorzata , Grobelny Marcin , Szmidt Jan
Published: September 2022

The paper presents the results of an investigation of the influence of technological parameters on the microstructure, optical, electrical and nanomechanical properties of zinc oxide coatings prepared using the pulsed reactive magnetron sputtering method. Three sets of ZnOx thin films were deposited in metallic, shallow dielectric and deep dielectric sputtering modes. Structural investigations showed that thin films deposited in the metallic mode were nanocrystalline with mixed hexagonal phases of metallic zinc and zinc oxide with crystallite size of 9.1 and 6.0 nm, respectively. On the contrary, the coatings deposited in both dielectric modes had a nanocrystalline ZnO structure with an average crystallite size smaller than 10 nm. Moreover, coatings deposited in the dielectric modes had an average transmission of 84% in the visible wavelength range, while thin films deposited in the metallic mode were opaque. Measurements of electrical properties revealed that the resistivity of as-deposited thin films was in the range of 10−4 Ωcm to 108 Ωcm. Coatings deposited in the metallic mode had the lowest hardness of 2.2 GPa and the worst scratch resistance among all sputtered coatings, whereas the best mechanical properties were obtained for the film sputtered in the deep dielectric mode. The obtained hardness of 11.5 GPa is one of the highest reported to date in the literature for undoped ZnO.
Corrosion Properties of Boron- and Manganese-Alloyed Stainless Steels as a Material for the Bipolar Plates of PEM Fuel Cells
Authors: Lovaši Tomáš , Pečinka Vojtěch , Ludvík Jakub , Kubásek Jiří , Průša Filip , Kouřil Milan
Published: September 2022

Stainless steels are materials that could be used for constructing not only the bearing parts of fuel cells but also the functional ones, particularly the bipolar plates. The advantage of stainless steel is its valuable electrical and thermal conductivity, reasonably low cost, excellent mechanical properties, and good formability. Paradoxically, the self-protection effect resulting from passivation turns into the main disadvantage, which is unacceptable interfacial contact resistance. The aim of this study was to test a number of possible stainless steels in a simulated fuel cell environment, especially those alloyed with boron and manganese, which were found to improve the contact resistance properties of stainless steels. The primary focus of the study is to determine the corrosion resistance of the individual materials tested. Electrochemical tests and contact resistance measurements were performed following the DOE requirements. Manganese-alloyed LDX stainless steel achieved the best results in the electrochemical tests; the worst were achieved by boron-containing steels. Boron-containing stainless steels suffered from localized corrosion resulting from chromium-rich boride formation. All steels tested exceeded the DOE limit in the contact resistance measurement, with 316L reaching the lowest values.
Mechanical Properties and Failure Mechanism of Anchored Bedding Rock Material under Impact Loading
Authors: Wu Yunhao , Liu Xuesheng , Tan Yunliang , Ma Qing , Fan Deyuan , Yang Mingjie , Wang Xin , Li Guoqing
Published: September 2022

In view of the problem that anchored bedding rock material is prone to instability and failure under impact loading in the process of deep coal mining, and taking the lower roadway of a deep 2424 coal working face in the Suncun coal mine as the engineering background, a mechanical model of anchored bedding rock material was established, and the instability criterion of compression and shear failure of anchored bedding rock material was obtained. Then, the separated Hopkinson pressure bar was used to carry out an impact-loading test on the anchored bedding rock material, and the dynamic mechanical properties of the rock with different anchoring modes and bolt bedding angles were studied; the evolution law of the strain field of the anchored bedding rock material was also obtained. The results show the following: (1) The bolt support could effectively improve the dynamic load strength and dynamic elastic modulus of the rock material with anchorage bedding, the degree of improvement increased with the increase in the angle of the bolt bedding, and the full anchorage effect was much higher than the end anchorage effect was. (2) The bolt bedding angle and anchorage mode greatly influenced crack development and displacement characteristics. After an impact, the bedding rock material had obvious shear displacement along the bedding direction, and obvious macroscopic cracks were produced in the bedding plane. The research results offer theoretical guidance to and have reference significance for deep roadway anchorage support engineering.
Predictive Monitoring System for Autonomous Mobile Robots Battery Management Using the Industrial Internet of Things Technology
Authors: Krot Kamil , Iskierka Grzegorz , Poskart Bartosz , Gola Arkadiusz
Published: September 2022

The core of the research focuses on analyzing the discharge characteristic of a lithium NMC battery in an autonomous mobile robot, which can be used as a model to predict its future states depending on the amount of missions queued. In the presented practical example, an autonomous mobile robot is used for in-house transportation, where its missions are queued or delegated to other robots in the system depending on the robots’ predicted state of charge. The system with the implemented models has been tested in three scenarios, simulating real-life use cases, and has been examined in the context of the number of missions executed in total. The main finding of the research is that the battery discharge characteristic stays consistent regardless of the mission type or length, making it usable as a model for the predictive monitoring system, which allows for detection of obstruction of the default shortest paths for the programmed missions. The model is used to aid the maintenance department with information on any anomalies detected in the robot’s path or the behavior of the battery, making the transportation process safer and more efficient by alerting the employees to take action or delegate the excessive tasks to other robots.
Poly(sodium acrylate)-Modified Magnetite Nanoparticles for Separation of Heavy Metals from Aqueous Solutions
Authors: Bobik Magdalena , Korus Irena , Synoradzki Karol , Wojnarowicz Jacek , Biniaś Dorota , Biniaś Włodzimierz
Published: September 2022

Two types of magnetite nanoparticles: unmodified (Fe3O4 NPs), and modified with poly(sodium acrylate) (Fe3O4/PSA NPs) were synthesized by the co-precipitation method and characterized using different techniques: X-ray diffraction (XRD), transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), Brunauer–Emmett–Teller (BET) adsorption, Fourier-transform infrared spectroscopy (FTIR). Additionally, magnetic properties and the effect of pH on the zeta potential were analyzed for both types of nanoparticles. Magnetites were used as adsorbents for seven heavy metal ions (Zn(II), Cu(II), Ni(II), Cd(II), Pb(II), Cr(III), Cr(VI)) within the pH range of 3–7. Research revealed nanometric particle sizes, a specific surface area of 140–145 m2/g, and superparamagnetic properties of both tested materials. Moreover, the presence of PSA functional groups in modified magnetite was confirmed, which lowered the pH of the isoelectric point. Both types of magnetite were effective metal ion adsorbents, with metal cations more effectively removed on Fe3O4/PSA NPs and Cr(VI) anions on Fe3O4 NPs. The adsorption of most of the examined cations (performed at pH = 5) can be well described by the Langmuir isotherm model, whereas the adsorption of Cr(VI) ions on modified magnetite correlated better with the Freundlich model. The Dubinin–Radushkevich model confirmed that chemisorption is the predominant process. The adsorption of all metal ions was well-characterized by the pseudo-second-order kinetic model.