This paper presents double shear tests performed to investigate factors influencing the bond behavior between basalt fiber-reinforced polymer (BFRP), glass fiber-reinforced polymer (GFRP) laminate, ...and concrete blocks. In detail, thirty-six twin concrete blocks strengthened with the aforementioned FRP types were tested to evaluate the influence of FRP length, width, and thickness, and their bonding behavior. The 2D-DIC (digital image correlation) technique and several strain gauges bonded along the laminate were used to measure the strain distributions of the FRP-to-concrete interface. The failure mode, ultimate load, load–slip, strain distribution, and bond–slip relationships between the laminates and concrete were analyzed. Furthermore, bond–slip curves were compared with some other existing literature models. The results from the experiment showed that the ultimate load, peak bond stress, and slip increased with the increase in the BFRP and GFRP laminates length, width, and thickness. The values of peak shear stress and the corresponding maximum shear slip were significantly different because of the above-mentioned factors’ influence on them. The bond interface that contributes to the bearing of the shear load may grow to an extent and later shift from the loaded end when debonding progresses. Finally, the fractured surfaces of the failed FRP laminates were examined using scanning electron microscope (SEM), revealing that FRP rupture, debonding in concrete, and debonding in an adhesive–concrete interface were the main failure types.
This work aims to evaluate the failure mechanisms of plain glass and basalt fiber reinforced composites and a selected glass/basalt hybrid composite sequence subjected to artificial seawater ...conditions. Sets of plain and five hybrid composite configurations were fabricated by vacuum assisted resin injection technique (VARI), and subjected to seawater aged for 258 days at 30 °C and 70 °C followed by tensile, flexural and charpy impact testing, respectively. Failure analysis for dry and seawater-aged composites were undertaken using scanning electron microscopy (SEM). Results showed that some hybrid laminates with sandwich-like and alternating sequencing exhibited superior mechanical properties and ageing resistance than plain laminates. GB3 (B2G2S) type hybrid composite with basalt fiber outer plies retained 100% tensile strength and 86.6% flexural strength after ageing, which was the highest among all the laminates. However, GB4 (BGBGS) type specimen with alternating sequencing retained the highest residual impact strength after ageing. SEM analysis on the failed specimens showed fiber breaking, matrix cracking and debonding caused by fiber–matrix interface degradation due to seawater exposure. However different hybrid configurations to a considerable extent prevented crack propagation across specimens, hence altering the overall damage morphology among different specimens.
The purpose of this study is to investigate the influence of adhesive types on the interfacial behavior of externally bonded basalt fiber reinforced polymer (BFRP) sheet-concrete substrate. Twelve ...manufactured double-lap shear samples were tested using four bonding adhesives. The strains on the surface of BFRP‐concrete joint were determined using electrical resistance strain gauge together with two‐dimensional digital image correlation technique (2D‐DIC). Experimental results show that properties of different bonding adhesives i.e., stiff (linear elastic, higher strength) and soft (nonlinear elastic, lower modulus, higher ultimate strain) has a significant impact on the failure mode, stiffness, ultimate load, strain and shear stress distribution nonetheless not so much on bond-slip relationship. The failure modes of specimens changed from interfacial debonding or cohesive failure in concrete substrate for stiff adhesive specimens to debonding in adhesive layer when soft adhesives are used. Stiff adhesive interfaces experienced higher ultimate loads from 1.1 to 1.3 times higher than soft adhesive interface. Meanwhile soft adhesives are shown to possess a lower maximum shear stress, higher interfacial fracture energy and longer stress transfer length.
A number of studies have identified interfacial debonding as a major challenge in externally bonded FRP strengthened systems. The addition of steel fiber into concrete enhances the debonding ...resistance, ductility and subsequently increase the strength of FRP laminate-concrete interface. The main purpose of this experiment is to explore the incorporation of different steel fiber contents in the interfacial bond between CFRP laminates and concrete substrate. Five groups of the double shear specimens were fabricated with hooked-end short steel fibers having five different volume contents namely; 0, 0.25%, 0.5%, 1.0%, and 1.5%. The impact of different fiber volume content on the maximum shear stress, slip at maximum shear stress and interfacial bond stress-slip relationship were analyzed. Results showed specimens with 0.25%–1.5% short steel fibers improved their maximum shear stress considerably over the control specimens. The failure modes of specimens were debonding in concrete substrate and concrete shear failure. Finally, an analytical interfacial bond-slip model considering the influence of volume fraction of short steel fibers is proposed.
Glass and basalt fiber reinforced vinyl ester epoxy (GFRP and BFRP) composites offer considerable potential for underwater and deep sea applications. In spite of their increasing usage in various ...sectors, there are still questions concerning their long term reliability in marine environment. In this article, the response of GFRP and BFRP to seawater ageing and their subsequent mechanical properties were evaluated. The composites were fabricated by vacuum assisted resin injection technique and seawater aged at 30 0C for 18, 28, 38, 258 and 305 days. By using scanning electron microscope (SEM), the failure of dry and seawater aged specimen after mechanical testing showed fiber breaking, debonding and sporadic fracturing along the laminate. This was due to higher moisture concentration in these areas during ageing. The results also revealed an overall steady decrease in tensile, flexural and impact strengths of seawater aged laminates with increasing ageing duration. Overall, the seawater ageing property of BFRP composites is almost identical to that of GFRP. The use of different nano-materials could also be explored in future works to address some drawbacks in the fiber–matrix interface durability after seawater ageing.
In the absence of microscopy, Plasmodium falciparum histidine-rich proteins 2 (PfHRP2)-based rapid diagnostic tests (RDTs) are recommended for the diagnosis of falciparum malaria, particularly in ...endemic regions. However, genetic variability of the pfhrp2 gene threatens the usefulness of the test due to its impact on RDT sensitivity. This study aimed to investigate the diversity of pfhrp2 in malaria cases among children in Ghana.
A cross-sectional study was conducted at the Adidome Government Hospital in the Volta Region of Ghana. A total of 50 children with mean age of 6.6 ± 3.5 years and diagnosed falciparum malaria were included. Blood samples were collected for complete blood count, malaria parasite identification and counting using auto analyzer and microscopy, respectively. DNA was isolated from blood-spotted Whatman filters, amplified and sequenced. Nucleotide sequences were translated in silico to corresponding amino acids and the deduced amino acids sequences were analyzed for diversity using Mega X.
The number of repeats and number of each repeat within PfHRP2 varied between isolates. Twelve rare PfHRP2 repeat types, two of which are previously unreported, were identified in this study. The HRP2 sequence obtained in this study shared high similarities with isolates from Kenya. Using Baker's regression model, Group B was the highest occurring type (58.0%). Screening of all sequences for epitopes recognized by PfHRP2-specific monoclonal antibodies (mAbs), the predominant motif was AHHAADAHH, which is recognized by the C1-13 mAbs.
This study reports diversity of P. falciparum HRP2 in samples from Ghanaian children with symptomatic malaria. The findings of this study highlight the existence of extra amino acid repeat types which adds to the PfHRP2 antigenic variability.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This study investigates the impact of workplace bullying on nurses' psychological distress and the quality of care as well as the impact of resilience in mitigating the negative effect of workplace ...bullying.
A cross-sectional survey design was employed to study the phenomenon among a purposive sample of 326 nurses in the Ghanaian healthcare sector with self-administered questionnaires for data collection. Data was analyzed using IBM’s Statistical Package for Social Sciences (SPSS) version 27.0 and Process Macro Version.
The study found evidence that bullied nurses in hospitals often suffer from psychological distress. Results also demonstrate a negative link between workplace bullying and the quality of care delivered by nurses. Furthermore, the study found that resilience moderated the workplace bullying and nurses' psychological distress relationship, however, resilience is not a significant moderator in the workplace bullying and quality of care relationship.
The study advances our understanding of workplace bullying's consequences for nurses in the Ghanaian healthcare sector. It underscores the importance of addressing workplace bullying, offering practical recommendations for healthcare administrators and managers. Fostering personal resources like resilience is crucial to empower nurses in facing the challenges of their workplace environment effectively.
Purpose>The main purpose of this study was to assess constraints and determinants of pineapple farmers' choice of certification schemes in Ghana.Design/methodology/approach>A multistage sampling ...method was used to solicit data from 345 pineapple farmers from Eastern and Central regions of Ghana. Analytical techniques including descriptive statistics, four-point Likert scale index and multinomial logistic regression model (MNL) were used to analyze the data.Findings>The four-point scale index shows that high renewal fee for certification schemes is the most important constraint facing certified farmers before high labor cost of production. The MNL model shows that both off-farm income and age negatively influenced farmers' choice of GlobalG.A.P scheme. However, household size had significant positive influence on farmers' choice of GlobalG.A.P and Organic schemes. Likewise, formal education had significant positive relationship with the choice of Fairtrade and Organic certification schemes while farming experience positively influenced organic scheme choice. On the other hand, premium price and extension services positively influenced the likelihood of choosing all the three certification schemes. Lastly, regional dummy only negatively influences the choice of organic certification schemes.Research limitations/implications>This study contributes to the literature on certification schemes adopted by smallholder by analyzing the determinants and constraints of choice of scheme(s).Originality/value>The study brings to bear the issues confronting smallholder pineapple farmers in the employment of certification schemes in developing countries, specifically Ghana.
The physical demands of caring for children and adolescents diagnosed with cancer, over a lengthy period, exert significant strain on the health and well-being of family caregivers. The capacity of ...family caregivers to surmount and cope with the various strains they experience due to the diagnosis and treatment trajectory is essential to the quality of life of the child and adolescent who has been diagnosed with cancer. However, the experiences of family caregivers have been under-explored. This study explored the strains, resources, and coping strategies of family caregivers of children and adolescents diagnosed with cancer in Ghana. Guided by a descriptive phenomenological design, 20 semi-structured interviews with family caregivers were conducted at a tertiary health facility that provides paediatric oncology services. The study was conducted between June and October 2022. The interviews were transcribed verbatim, translated and coded using NVivo software. An inductive thematic analysis approach using Vaismoradi et al.'s thematic analysis framework was followed in analysing the data. The study revealed that family caregivers of children diagnosed with cancer experienced three main strains: somatic strains (poor sleep quality, loss of appetite, and unintended weight loss), economic strains (financial burden and loss of economic livelihood), and psychosocial strains (isolation from social activities and network, frustration and helplessness, and balancing multiple family needs). The following themes emerged as coping resources: family cohesiveness, community support, and support from health care providers. Coping strategies that emerged included trusting in God and being self-motivated. The study concludes that family caregivers experience somatic, economic, and psychosocial strains. However, they can leverage available resources (family cohesiveness, community support, and support from healthcare providers) to cope with these strains. There is a need to educate and sensitize family caregivers about the potential strains that they are likely to experience prior to the assumption of care roles. Also, the formal inclusion of non-governmental organizations and religious bodies will ensure that family caregivers receive sufficient community support to cope with the strains of caregiving.
Poultry enterprise is challenged with high economic losses due to viral infections. The outbreak of such infections, including Newcastle disease, avian influenza, infectious bronchitis and infectious ...bursal disease, could undermine poultry performance leading to decreased meat and egg production. The potency of vaccines in recent times has dropped with the rise in the virulence of antigens, which can interrupt vaccination defence. Natural herbs and phytochemicals have been extensively recommended because of their vast advantageous effects. Garlic and its bioactive organo-sulphur compounds have been proven to have antiviral, immunomodulatory and other pharmaceutical properties. Remarkable effects in poultry include a decrease in viral loads, an increase in antibody titres, lessening inflammatory cytokines and augmenting antiviral gene expression; however, methods of preparation, the dose of bioactive compounds and proportions administered may cause disparities in different reports. Therefore, this review highlights the potential of garlic against viral diseases, immunomodulatory, toxicity and pathological status in embryonated chicken eggs and poultry.
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