bluuebunny/crossref_metadata_2025 huggingface dataset:
Community bylaws concerning sexual and reproductive health and rights in Machinga District, Malawi: to what extent are they responsive to young people’s needs?
Authors: Kok Maryse , Munthali Alister , Mvula Peter , Chisiza Zindaba , Mat Marielle Le
Published: November 2023

Background

Community bylaws are commonly accepted mechanisms to influence behaviour change to achieve better health and development outcomes in sub-Saharan Africa. However, the uses, benefits, and potential downsides of community bylaws are largely unclear, especially regarding sexual and reproductive health and rights (SRHR) of young people. The objective of this study was to determine the extent to which community bylaws in Machinga District in southern Malawi are responsive to young people’s realities and SRHR needs.

Methods

In Phase 1 of this qualitative study, 35 community members were interviewed, including 14 young people (15–24 years), five parents, five traditional leaders, and eleven key informants. Based on findings from Phase 1, eleven members from local youth groups co-created a drama performance that covered issues concerning bylaws and young people’s SRHR (Phase 2). The drama was performed in the community, after which young women (18–24 years), young men (17–24 years), female and male parents discussed on what they saw in the drama, focusing on young people’s SRHR, in four focus group discussions (Phase 3). All transcripts were coded and thematically analysed and narratives were written on main themes.

Results

Three community SRHR bylaws, related to teenage pregnancy, child marriage, and sexual harassment and rape were identified and commonly accepted in the community. While these bylaws intend to reduce SRHR-related issues among young people, they are often not involved in bylaw formulation. The bylaws were associated with protection of girls, and a good reputation for boys, young men and traditional leaders. Bylaw enforcement faced problems, as fines were not in line with national laws, and wealthy offenders could avoid them through bribes. Effects of bylaws on teenage pregnancy rates seemed limited, while some positive effects on school readmission, prevention of child marriage, and reporting sexual harassment were reported.

Conclusions

The study revealed that community bylaws were accepted but not owned by young people, and had different effects on the rich versus the poor, and girls versus young men. Bylaws were associated with punishment in terms of money, which seemed to overpower their potential to promote rights and address social norms underlying SRHR issues of the youth.
A candidate nanoparticle vaccine comprised of multiple epitopes of the African swine fever virus elicits a robust immune response
Authors: Song Jinxing , Wang Mengxiang , Zhou Lei , Tian Panpan , Sun ZhuoYa , Sun Junru , Wang Xuannian , Zhuang Guoqing , Jiang Dawei , Wu Yanan , Zhang Gaiping
Published: November 2023

The African swine fever (ASF) pandemics pose a significant threat to the global swine industry, and the development of safe and effective vaccines is a daunting but necessary challenge. The level and persistence of immunity are very important for the effectiveness of the vaccine. Targeting antigens to antigen presenting cells (APCs) can greatly enhance immunogenicity. In this study, we developed a self-assembled nano-ASFV vaccine candidate (NanoFVax) targeting DCs, by covalently coupling the self-assembled 24-mer ferritin with the dominant B and T cell epitopes of the highly immunogenic ASFV antigen (p72, CD2v, pB602L and p30) and fused with the chemokine receptor XCL1 (a DC targeting molecule) through the SpyTag/SpyCatcher protein ligase system. Compared to monomeric protein, the nanoparticle vaccines can induce a more robust T-cell response, and the high-level antibody response against ASFV can last for more than 231 days. Therefore, the NanoFVax is a novel and promising vaccine candidate for ASFV.

Graphical Abstract
“It’s starting to weigh on me”: Exploring the Experiences and Support Needs of Harm Reduction Staff in Connecticut using the Social-Ecological Model
Authors: Hill Katherine , Dunham Katherine , Grau Lauretta E. , Heimer Robert
Published: November 2023

Background

The experiences and perceived support needs of harm reduction workers in the USA have been understudied. While previous research has explored staff burnout and role-related stress, there is a research gap around potential supports for staff wellbeing and individual longevity in their roles. This is especially critical given the growing overdose crisis and the need for sustainable harm reduction programming. Thus, we sought to describe the experiences of harm reduction staff and identify the perceived support that could empower harm reduction staff to successfully navigate their roles.

Methods

Purposive sampling methods were used to recruit harm reduction staff working in Connecticut. Seventeen semi-structured, one-on-one interviews were conducted between December 2022 and March 2023. Participants were asked about their experiences with role-related stressors and supports. Informed by the Social-Ecological Model, transcripts were coded using both inductive and deductive codes, and themes were developed using thematic analysis approaches.

Results

Study participants described their experiences working in harm reduction and the numerous ways they already are or could be receiving support in their roles. These experiences were organized into eight themes according to the levels of the Social-Ecological Model. At the individual level, participants explained that support could help them navigate the variability of the physical environment, boundary setting, and self-care. Relationships between clients and co-workers were both identified as means of support at the interpersonal level, helping participants navigate difficult situations and feelings of stress. At the organizational level, study participants explained how they look to their organization to provide sufficient support by way of training, staffing, compensation, and benefits. Additionally, participants stressed the importance of having supervisors who valued their work and provided emotional support. Lastly, at the community level, participants discussed how support was needed to help them navigate complex systems while working with a stigmatized population in an often-stigmatized field.

Conclusions

To best support harm reduction staff in their day-to-day roles, our findings underscore the need for support on multiple levels. Future research could explore how the provision of support to harm reduction staff impacts not only staff perceptions of support but also the success of clients accessing harm reduction services.
Aging and the impact of global DNA methylation, telomere shortening, and total oxidative status on sarcopenia and frailty syndrome
Authors: Kmiołek Tomasz , Filipowicz Gabriela , Bogucka Diana , Wajda Anna , Ejma-Multański Adam , Stypińska Barbara , Modzelewska Ewa , Kaliberda Yana , Radkowski Marcin , Targowski Tomasz , Wrona Julia , Paradowska-Gorycka Agnieszka
Published: November 2023

Aging is a biological event that influences many organs and systems. Both sarcopenia and frailty syndrome refer to geriatric conditions with overlapping phenotypes. Many mechanisms are involved in the aging process such as DNA methylation telomeres which are susceptible to oxidative stress, and inflammations which result in telomere shortening, leading to chromosomal instability. The study aimed to determine the associations between these processes, frailty and sarcopenia syndrome. Global DNA methylation was analyzed using the ELISA method. Telomere length was analyzed using qPCR. Total oxidative status (TOS) was analyzed using a colorimetric method. The present study revealed that the main factor affecting methylation, telomeres length and level of total oxidant stress was age.
Short-term outcomes following total correction of tetralogy of fallot in adult patients
Authors: Khajali Zahra , Mohammadi Nasibeh , Toloueitabar Yaser , Maleki Majid , Saedi Sedigheh , Norouzi Zeinab , Mazloum-Zadeh Saeedeh , Chenaghlou Maryam , Jalali Amirhossein , Tatari Hassan , Aliramezany Maryam
Published: November 2023

Objectives

Tetralogy of Fallot (TOF) is a common congenital heart disease which should be corrected. The recommended time for the Tetralogy of Fallot Total Correction (TFTC) surgery is during the infancy for the possible difficulties during the surgery and the related issues. However, sometimes TOF is diagnosed and managed during the adulthood.

Methods

This study is a descriptive and retrospective one which included all patients who underwent TFTC at the age of 15-year and older in 10 years (between the years 2010 and 2020) to identify short-term (in-hospital mortality, ICU stay, postoperative bleeding, respiratory complications after the surgery such as pulmonary edema, pneumonia, etc.) and one-year (left ventricle ejection fraction (LVEF), right ventricle (RV) ejection fraction, the severity of tricuspid and aortic regurgitation after surgery) outcomes. All data were taken from medical records at Rajaie Cardiovascular Medical and Research Center. Data were analyzed using SPSS 22.

Results

94 patients with the mean ± SD age of 26.7 ± 9.6 years were enrolled. Most of them were male (59.6%) (P-value: 0.009). In-hospital mortality in our study were 5.3%. Tricuspid regurgitation (TR) was significantly resolved after the surgery (P-value: 0.006). Of 17 (18.1%) patients with small or hypoplastic pulmonary artery (PA) branches, 14 patients had acceptable PA branch size after surgery.

Conclusion

TFTC at an older age is safe with acceptable results. Age is not a contraindication for TFTC and surgery should be recommended if the patients are diagnosed with TOF in adulthood. Also, the TOF diagnosis should be considered in adult patients with suspicious signs and symptoms.
Aortoesophageal fistula treated using one-stage total reconstruction: a case report from a high-volume center
Authors: Lee Yi-Ping , Ozaki Kensuke , Oshima Susumu , Hirokami Tomohiro
Published: November 2023

Background

Aortoesophageal fistula (AEF) is a rare but typically life-threatening condition. Although several treatment strategies exist, including conservative treatment with intraluminal stent graft and open thoracic aortic replacement, the overall outcome remains poor, ranging from 16 to 39%. Furthermore, esophageal reconstruction methods vary between hospitals. Herein, we report a case of aortoesophageal fistula treated using one-stage total reconstruction.

Case presentation

This case involved a 58-year-old woman who developed acute type A aortic dissection and underwent successful total arch replacement at the other hospital. However, she developed AEF 1 year later and underwent urgent thoracic endovascular aortic repair, which eventually failed. We performed thoracic aortic replacement, total esophagectomy, gastric tube reconstruction, and omental flap in a one-stage operation. The patient was extubated the next day and transferred to the general ward on postoperative day 3. Computed tomography revealed favorable results.

Conclusions

For postoperative AEF, dedicated debridement with reconstruction is more effective than conservative treatment. In an experienced center, post-procedure-related AEF can be easily treated using one-stage reconstruction.
Measurement and characteristics of the temporal-spatial evolution of China’s healthcare services efficiency
Authors: Ye Yizhong , Tao Qunshan
Published: November 2023

Background

Healthcare services efficiency (HSE) is directly related to the healthcare demands of the general public and also plays an essential role in the country’s coordinated economic and social development.

Methods

In this study, the stochastic frontier approach (SFA)-Malmquist model was applied to measure the HSE of 31 Chinese provinces based on panel data from 2010–2020. Then, kernel density estimation, Markov chain, and exploratory spatial data analysis were adopted to study the temporal-spatial dynamic evolution characteristics of the HSE.

Results

The study found that China’s HSE showed an average value of approximately 0.841, indicating room for improvement. The HSE varied significantly across regions, presenting an “East > Central > West” distribution layout. The TFP of healthcare services in China grew by 1.6% per year, driven mainly by technological progress of 1.8% per year. The trend of the HSE shifting to a high level in China was significant, but its evolution exhibited stability of maintaining the original state, and it was harder to achieve leapfrog transfer. The temporal-spatial evolution of the HSE was also significantly affected by geospatial factors, with a clear spatial spillover effect and spatial agglomeration characteristics. Provinces with high-level HSE exhibited positive spatial spillover effects, while provinces with low-level HSE had negative spatial spillover effects. Thus, the “club convergence” phenomenon of “high efficiency concentration, low efficiency agglomeration, high levels of radiation, and low levels of suppression” was formed in the spatial distribution.

Conclusions

The results indicate that countermeasures should be taken to improve the HSE in China. Theoretical support for the improvement of HSE is provided in this paper.
Current knowledge gaps in extracorporeal respiratory support
Authors: Tonetti Tommaso , Zanella Alberto , Pérez-Torres David , Grasselli Giacomo , Ranieri V. Marco
Published: November 2023

Extracorporeal life support (ECLS) for acute respiratory failure encompasses veno-venous extracorporeal membrane oxygenation (V-V ECMO) and extracorporeal carbon dioxide removal (ECCO2R). V-V ECMO is primarily used to treat severe acute respiratory distress syndrome (ARDS), characterized by life-threatening hypoxemia or ventilatory insufficiency with conventional protective settings. It employs an artificial lung with high blood flows, and allows improvement in gas exchange, correction of hypoxemia, and reduction of the workload on the native lung. On the other hand, ECCO2R focuses on carbon dioxide removal and ventilatory load reduction (“ultra-protective ventilation”) in moderate ARDS, or in avoiding pump failure in acute exacerbated chronic obstructive pulmonary disease. Clinical indications for V-V ECLS are tailored to individual patients, as there are no absolute contraindications. However, determining the ideal timing for initiating extracorporeal respiratory support remains uncertain. Current ECLS equipment faces issues like size and durability. Innovations include intravascular lung assist devices (ILADs) and pumpless devices, though they come with their own challenges. Efficient gas exchange relies on modern oxygenators using hollow fiber designs, but research is exploring microfluidic technology to improve oxygenator size, thrombogenicity, and blood flow capacity. Coagulation management during V-V ECLS is crucial due to common bleeding and thrombosis complications; indeed, anticoagulation strategies and monitoring systems require improvement, while surface coatings and new materials show promise. Moreover, pharmacokinetics during ECLS significantly impact antibiotic therapy, necessitating therapeutic drug monitoring for precise dosing. Managing native lung ventilation during V-V ECMO remains complex, requiring a careful balance between benefits and potential risks for spontaneously breathing patients. Moreover, weaning from V-V ECMO is recognized as an area of relevant uncertainty, requiring further research. In the last decade, the concept of Extracorporeal Organ Support (ECOS) for patients with multiple organ dysfunction has emerged, combining ECLS with other organ support therapies to provide a more holistic approach for critically ill patients. In this review, we aim at providing an in-depth overview of V-V ECMO and ECCO2R, addressing various aspects of their use, challenges, and potential future directions in research and development.
Regeneration of joint surface defects by transplantation of allogeneic cartilage: application of iPS cell-derived cartilage and immunogenicity
Authors: Abe Kengo , Tsumaki Noriyuki
Published: November 2023

Background

Because of its poor intrinsic repair capacity, articular cartilage seldom heals when damaged.

Main body

Regenerative treatment is expected for the treatment of articular cartilage damage, and allogeneic chondrocytes or cartilage have an advantage over autologous chondrocytes, which are limited in number. However, the presence or absence of an immune response has not been analyzed and remains controversial. Allogeneic-induced pluripotent stem cell (iPSC)–derived cartilage, a new resource for cartilage regeneration, reportedly survived and integrated with native cartilage after transplantation into chondral defects in knee joints without immune rejection in a recent primate model. Here, we review and discuss the immunogenicity of chondrocytes and the efficacy of allogeneic cartilage transplantation, including iPSC-derived cartilage.

Short conclusion

Allogeneic iPSC-derived cartilage transplantation, a new therapeutic option, could be a good indication for chondral defects, and the development of translational medical technology for articular cartilage damage is expected.
Maximizing the cost effectiveness of electric power generation through the integration of distributed generators: wind, hydro and solar power
Authors: Idoko Idoko Peter , Ayodele Temitope Raphael , Abolarin Sogo Mayokun , Ewim Daniel Raphael Ejike
Published: November 2023

Background

The transition towards renewable energy sources has become an imperative step to mitigate climate change, reduce carbon emissions and improve energy security and economic prosperity in a sustainable manner. Maximizing the cost effectiveness of electric power generation is crucial to making renewable energy sources viable and attractive options for clean energy production. The strategic allocation of wind, hydro and solar power systems is essential to achieving this goal. This paper attempts to demonstrate how the cost effectiveness of electrical power system could be maximized through the integration of wind, solar and hydropower systems and comparison at different penetration levels of 0, 25, 50, 75 and 100% on cost effectiveness of electric power generation. The different generator technologies were designed based on their electrical output attributions.

Results

The cost of electric generation for the integration of each generator at the various buses were calculated at different penetration level for fair comparison. The results indicate that the minimum money loss for the integration of solar power was $743.90 at bus 4 and at 50% penetration level, the minimum money loss for the integration of wind power was $999.00 at bus 4 and at 25% penetration level while the minimum amount loss for the integration of hydropower was $546.50 at bus 4 and at 75% penetration level.

Conclusions

The magnitude to which the integration of the different generator affects the cost effectiveness of power production hinges on the type of generator, the penetration level and the location of the generator in the grid.
Employee perception of electronic human resource management and COVID-19 restrictions in public organizations: the experience of Ghana Revenue Authority, Bono Region
Authors: Abane Juliana Abagsonema , Brenya Edward , Agyapong Andrews Boakye
Published: November 2023

The purpose of this study was to find out what measures were taken to manage human resources during the COVID-19 pandemic by the Ghana Revenue Authority in Ghana. This was necessary because, even though electronic human resource practices have been implemented in most public organizations in the country, it was uncertain whether or not these practices were vital in delivering public service during the peak of the pandemic at the regional level due to government restrictions implemented to curb the spread of the virus. The study used 78 employees of the Ghana Revenue Authority in the Bono Regional Office of the Ghana Revenue Authority. The study used inferential statistics by employing Pearson correlation and multiple regression techniques to test the effect of employee perceptions, electronic human resource management practices, and COVID-19 practices on electronic human resource adoption. The findings revealed that e-human resource practices had the strongest effect on e-human resource adoption with a beta value of 0.781 and apvalue of 0.000, followed by employee perception with a beta value of 0.272 and apvalue of 0.004. Significantly, the entire effect of the COVID-19 practices was statistically insignificant yet positive. Overall, the four regression models were significant (p < 0.01), with the fourth model indicatingR2to be 0.677 points. Based on the findings, the study recommends that the Ghana Revenue Authority focuses more on transformational human resource management strategies to increase employee adoption of electronic systems. Furthermore, it is suggested that the organization includes employees in new technologies that improve their performance. Our findings are significant because the outbreak of COVID-19 made scholars focus more on flextime, health and safety, and remote working practices. Little has been done to determine whether or not the new normal has impacted how electronic human resource practices have been implemented in public sector organizations compared to the private sector. So, this study stands out as one of the critical studies in electronic human resource management practices in sub-Saharan Africa.

Graphical Abstract
Reading for Time in How Europe Underdeveloped Africa
Authors: Drayton Richard
Published: November 2023

Walter Rodney’s How Europe Underdeveloped Africa (1972) examined, of course, how European imperialism turned Africa into a subordinate zone of the world economy. But beyond that, this essay seeks to show how Rodney explored, with Marxist and Caribbean tools, the complex problem of temporality in world history: how events in one conjuncture form enduring structures; how imperial power orders, and is reproduced by, ways of living in and thinking about time; and revolutionary time, in particular the Tricontinental moment. Rodney’s time conjuring was anchored both in that heroic 1960s emergency and in a tradition of challenging the constrictions of modern (imperial) time, alive in both elite and popular currents of the Caribbean intellectual tradition.
ENHANCING POLYLACTIC ACID (PLA) FOR 3D PRINTING WITH CELLULOSE NANOFIBERS VIA TWIN SCREW MELT EXTRUSION
Authors: BHAGANAGAR SIDDHARTH , BISWAS PIAS KUMAR , AGARWAL MANGILAL , DALIR HAMID
Published: November 2023

In this study, cellulose nanofiber (CNF) reinforced polylactic acid (PLA) filaments were made via melt extrusion for 3D printing applications. The use of CNF reinforcement may enhance the PLA's mechanical attributes, making it a better material for a variety of 3D printing applications. In order to create the nanocomposites, a master batch of PLA and CNFs was premixed, and the CNFs were subsequently diluted throughout the extrusion process to final concentrations of 1, 3, and 5 wt%. The dilution was done to evaluate how the morphological and mechanical characteristics of the composites would be affected by different CNF concentrations. The findings demonstrated that adding 3 wt. % CNF greatly improved the mechanical characteristics of the PLA composites. In particular, the flexural strength rose by 60.2%, the compressive strength rose by 62.7%, and the tensile strength rose by 77.7%. These results show that the melt extrusion of PLA filaments reinforced with CNF is a practical method for creating nanocomposites with enhanced mechanical characteristics for 3D printing applications. The study's conclusion emphasizes how CNF reinforcement may be used to enhance the mechanical characteristics of PLA for 3D printing applications. The findings may be useful for researchers and businesses in the 3D printing and materials science fields, and they may also aid in the creation of more sophisticated and environmentally friendly 3D printing materials.
DEVELOPMENT OF NOVEL CARBON FIBER BASED ELECTRODES FOR LITHIUM-ION BATTERIES
Authors: KAYNAN OZGE , RAJ AYUSH , CARROLA MIA , CASTANEDA HOMERO , ASADI AMIR
Published: November 2023

Carbon fiber-based structural lithium-ion batteries are attracting significant attention in the automotive and aerospace industries due to their dual capability of energy storage and mechanical load-bearing, leading to weight reduction. These batteries utilize lightweight carbon fiber (CF) composites, which offer excellent stiffness, strength-to-weight ratios, and electrical conductivity. Polyacrylonitrile-based CFs, comprising graphitic and amorphous carbon, are particularly suitable for Li-ion battery applications as they allow the storage of lithium ions. However, integrating lithium iron phosphate (LFP) into CFs poses challenges due to complex lab-scale processes and the use of toxic dispersants, hindering large-scale industrial compatibility. To address this, we investigate the development of water-based LFPintegrated CF structural Li-ion batteries. Homogeneous suspensions are created using cellulose nanocrystals (CNCs) to form hybrid structures. The battery system employs LFP-modified CF as the cathode, unsized CF as the anode, and a water-based electrolyte. The LFP-CNC-graphene nanoplatelet (GNP) hybrids are coated onto CFs through immersion coating. Scanning electron microscopy (SEM) images confirm the well-dispersed and well-adhered LFP-CNC-GNP structures on the CF surface, contributing to their mechanical interlocking and electrochemical performance. The batteries demonstrate a specific energy density of 62.67 Wh/kg and a specific capacity of 72.7 mAh/g. Furthermore, the cyclic voltammetry experiments reveal the stability of the LFP-CNC-GNP-coated CF batteries over 200 cycles without degradation. This research enables the engineering of hybrid nanostructured battery laminates using novel LFP-CNC-GNP-coated CFs, opening avenues for the development of innovative Li-ion structural batteries.
MESOSCALE MODELING AND HOMOGENIZATION OF WOVEN CARBON FIBER COMPOSITES
Authors: CREVELING PETER J. , SOMMER DREW , COLLINS LINCOLN N. , ROBERTS SCOTT A.
Published: November 2023

In this study, we investigated the impact of varying boundary conditions and simulation domain size on the calculation of homogenized elastic moduli, Poisson’s ratio, thermal expansion, and cure shrinkage for woven carbon composites. The boundary conditions of interest included kinematically uniform (KUBC), statically uniform (SUBC), and periodic (PBC). Stress and strain distributions were compared across the entire simulation domain and for sub-volume regions of interest when the domain size was increased. Additionally, homogenized properties were quantified and compared across varying domain sizes. Key results show that effective moduli determined using KUBCs and SUBCs provide upper and lower limits that bounded values determined using PBCs. However, for out-of-plane thermal expansion and cure shrinkage, the effective values were not bounded by the values determined using KUBCs and SUBCs. Thermal expansion coefficients determined using KUBCs and SUBCs were underpredicted compared to values obtained from PBCs. Similarly, cure shrinkage determined using KUBCs and SUBCs were overpredicted compared to values obtain from PBCs. Lastly, it was shown that homogenized values obtain using PBCs could be well approximated using KUBCs or SUBCs with an increased domain size. Specifically, homogenized properties determined using KUBCs or SUBCs exhibited fast convergence to the periodic solution when the simulation domain size was increase both in-plane and out-of-plane, followed by calculation of properties from the centrally located unit cell within the domain.
EFFECT OF REPRESENTATIVE VOLUME ELEMENT SIZE FOR CREATING STATISTICALLY EQUIVALENT COMPOSITE MICROSTRUCTURES
Authors: HUSSEINI JAMAL F. , STAPLETON SCOTT E. , POURKAMALI-ANARAKI FARHAD
Published: November 2023

Micromechanical models of fiber reinforced composites often need to have fiber arrangements which are equivalent to manufacture samples to capture local features such as fiber clusters or matrix pockets which may impact failure. These features can vary in size, requiring that models must be large enough to capture features which may be most important. In this study, different size windows of larger composite scans were sampled, and descriptors were measured which characterize fiber and matrix dense regions. Statistically equivalent microstructures to these windows were generated and simulated for transverse strength and stiffness using a reduced order micromechanical model. Results showed that certain statistics could be captured by smaller window sizes compared to larger, and that some statistics could not be captured by the largest window size. Also shown is how transverse strength and stiffness varied depending on microstructure size.
TENSILE PROPERTIES OF UNIDIRECTIONAL POLYMER COMPOSITES REINFORCED BY ALIGNED CARBON NANOTUBE YARNS
Authors: NADERI ALI , TARAFDAR AMIRREZA , LIN WENHUA , WANG YEQING
Published: November 2023

Carbon nanotubes (CNTs), as they possess outstanding mechanical properties and low density, are considered as one of the most promising reinforcements in composite structures. Due to their capability of transferring loads, CNTs in long continuous forms such as yarns and tapes can withstand 20 times as much load as steel can do at the same weight. In this research, carbon nanotube yarns were wound onto an aluminum plate using a custom-built fixture to fabricate a unidirectional strip. Then, by brushing epoxy resin on the strip and laminating four layers, the unidirectional CNT reinforced epoxy resin composite beam specimens were produced. The mechanical properties of the unidirectional CNT-reinforced composite (CNTRC) were determined using standard tensile tests. This study presents a method for manufacturing CNTRC out of CNT yarns, determining the CNTRC’s Young’s modulus as well as the tensile strength, and obtaining its strain field via digital image correlation (DIC) method. It is observed that the pressure due to sandwiching of the aluminum plates during the manufacturing process leads to nonuniformity of the specimen in the width along midspan of the longitudinal direction which results in the specimen’s not being perfectly unidirectional. This phenomenon can cause the matrix cracking in tensile test and reduce the ultimate tensile strength up to 78% in comparison with perfectly unidirectional specimens. However, the Young’s modulus of such composites is comparable with those obtained from previously existing research. Also, Results from DIC showed the possible failure prone areas in the specimens, as it presents a up to 64% difference between the highest and lowest strain in the tensile loading direction through the specimens. This study will serve as a foundation for future research involving CNT composites, particularly the use of their high anisotropy to produce auxetic composites with large negative Poisson’s ratios.
MAPPING PROCESS MODEL RESULTS TO FRACTURE MODEL INITIAL CONDITIONS FOR ADHESIVE BONDING
Authors: . BERGAN ANDREW C. , SREEKANTAMURTHY THAMMAIA , RATCLIFFE JAMES G. , CARVALHO NELSON V. DE
Published: November 2023

A systematic approach is proposed for mapping adhesive bonding process outcomes to initial conditions for progressive damage analysis (PDA). Herein, two mapping procedures are developed: 1) direct mapping for residual stresses, strains, and deformations obtained from a process model; and 2) functional mapping for quantities such as bondline thickness, degree of cure, and porosity that are assumed to have a functional relationship with fracture toughness but are not discretely modeled in the PDA. The spatial distribution of functionally mapped quantities may be determined by process modeling or inspection. The functional maps between the quantity of interest and fracture toughness may be obtained from independent lower-scale numerical simulations or empirical test campaigns. The proposed mapping procedure links the adhesive bonding process to the structural performance. Therefore, by accounting for the effects of bondline nonuniformities in structural analysis, analytical predictive accuracy can be improved, and off-nominal conditions can be evaluated. The mapping procedures are demonstrated and verified with example problems.
OPTIMIZATION OF VARIABLE THICKNESS AND STIFFNESS COMPOSITE PLATE BUCKLING LOAD USING FEM ANDSEMI-ANALYTICAL METHOD
Authors: DAVIDSON PAUL , LIN SHIYAO , NGUYEN HOANG , WAAS ANTHONY , CALL DAMON , TORRES EDUARDO , ESTERBAN INIGO
Published: November 2023

In this study we report results on the manufacturing and response of cylindrical sandwich panels subjected to axial compressive loads. The structural panels were manufactured using Out-of-Autoclave (OOA) carbon fiber composite face sheets and aluminum hex core, using Automated Fiber Placement (AFP) manufacturing. Two types of panels were manufactured: pristine panels with straight fiber paths, and steered fiber panels, to examine the influence of fiber steering, gaps and overlaps on the compressive buckling response. Panel testing used specially designed fixtures, and digital image correlation (DIC) for diagnostics along with point wise out of plane displacement measurements using a laser scanning system. Test results indicated that sandwich panels failed due to skin compressive failure leading to disbonding, rather than global panel buckling. Steered panels showed marginal decrease in strength.
QUANTIFICATION OF LOW VELOCITY IMPACT (LVI) DELAMINATION FROM ULTRASOUND (UT) INSPECTION DATA AND MACHINE LEARNING
Authors: DAVIDSON PAUL
Published: November 2023

In this paper we demonstrate the use of machine learning for segmentation of raw ultrasound scan of impacted composite panels. The methodology implemented describes the use of data augmentation, where sparse real data is augmented with synthetic data, to enable use of convolutional neural network for machine learning. Initial results indicate that the approach is able to segment the delamination patter with good accuracy.
MODIFIED MODE I COHESIVE TRACTION-SEPARATION LAW FOR Z-PINNED COMPOSITE
Authors: DAVIDSON PAUL
Published: November 2023

In this study a detailed numerical analysis is conducted to determine the traction-separation curve for z-pin under mode-I loading state. A single z-pin is modeled and studied with pre-stress and friction and cohesive interface modeled, to determine the traction-separation curves in mode-I. The results show that a traditional bi-linear or tri-linear traction separation curve is insufficient to capture the bending of z-pin and consequent frictional dissipation due to z-pin. Based on this a new approach to parameterize traction-separation is proposed.
IMPROVING JOINT STRENGTH PREDICTION BY ACCOUNTING FOR DEFECTS IN TENSILE TESTING SPECIMENS
Authors: GHAFFARI SEYEDEH HENGAMEH , SCHMIDT DANIEL , STAPLETON SCOTT E.
Published: November 2023

Adhesively bonded joints are widely used in various industries, highlighting the importance of understanding their behavior. While fracture toughness tests provide valuable insights, they are complex and time-consuming. As a result, engineers often rely on tensile test data alone, considering its simplicity and practicality. However, the prevalence of defects in tensile specimens can lead to an underestimation of adhesive elongation at break. Tensile specimens distribute loads over a larger area, making them more susceptible to premature failure caused by localized flaws compared to bond line loads. To address this limitation and improve accuracy, this study proposes a novel approach. Tensile tests are conducted to determine the distribution of elongation at break, and inverse modeling using User Material (UMAT) in ABAQUS is employed to acquire the defect distribution in the specimens for different mesh sizes. Single Lap Joint (SLJ) tension tests are performed to compare force-displacement results from experimental data with simulation. The results highlight the significance of considering proper flaw distribution in the adhesive layer. By incorporating the defect distribution obtained from inverse modeling, the prediction of failure displacement can be enhanced compared to using adhesive with uniform properties based solely on average tensile data.
PREDICTION OF EFFECTIVE ELASTIC PROPERTIES OF CARBON/UHMWPE NANOCOMPOSITES BY COMBINATION OF NUMERICAL AND ANALYTICAL MODELING
Authors: BUKLOVSKYI STANISLAV , MIROSHNICHENKO KATERYNA , TSUKROV IGOR , THOMSON REBECCA J. , SOLBERG PEDER C. , CITTERS DOUGLAS W. VAN
Published: November 2023

In this paper, we investigate ultra-high-molecular-weight-polyethylene (UHMWPE) doped with conductive carbon black (CCB) nanoparticles. This nanocomposite is considered a candidate for biomedical applications such as orthopedics. Micro-computed tomography (μCT) and scanning electron microscopy studies show that the composite has a complex microstructure consisting of larger particles of UHMWPE surrounded by a thin layer containing a high concentration of CCB nano inclusions. The overall mechanical properties of these composites depend on the volume fraction of CCB and the manufacturing procedures e.g., compression molding or equal channel angular extrusion. To predict the effective elastic properties of the CCB/UHMWPE nanocomposite, we propose a multiscale modeling framework based on a combined analytical-numerical approach. μCT images are processed to extract the size, shape, and orientation distributions of UHMWPE particles as well as the volume fractions and spatial distribution of CCB containing layer. These distributions are used to develop multiscale numerical models of the composite including finite element analysis of representative volume elements on the mesoscale, and micromechanical predictions of CCB containing layer on the microscale. The predictive ability of the models is confirmed by comparison with the experimental measurements obtained by dynamic mechanical analysis.
A COUPLED EXPERIMENTAL-NUMERICAL METHOD DEDICATED TO THE DYNAMIC CHARACTERIZATION OF COMPOSITE BRAIDS UNDER DROP WEIGHT CONDITIONS
Authors: RALLO M. , FERRERO J. F. , MARGUET S. , NAVARRO P. , MEUR K. LE
Published: November 2023

Bird strike simulation is crucial for designing aircraft blades, but characterizing materials at high strain rates presents challenges. This study presents a Dynamic Tensile Test Device (DTTD) for characterizing composite materials usually used in blades industry. The DTTD, integrated with a drop weight tower, converts kinetic energy into tensile loading, allowing material characterization of any material. In this article, experimental results for aramid/epoxy 2D braids at different angles were obtained and load curves were analyzed. However, the effort is produced by an impact, which generates a shock wave that must pass through the system, resulting in several vibrations that makes the primary results difficult to exploit. To overcome this, a finite element (FE) model of the drop tower system was created for reverse engineering material characterization. This approach enables material characterization and strain rate analysis. Further investigations can explore additional braid angles and refine the modeling techniques.
PERIDYNAMICS FOR MICROSTRUCTURAL DAMAGE MODELING OF 3D CARBON/CARBON (C/C) COMPOSITE MATERIALS
Authors: MADENCI ERDOGAN , BARUT ATILA , YAGHOOBI AMIN , YAO ZHIYANG , HU YILE
Published: November 2023

This study presents a peridynamic model to investigate damage initiation in complex 3D C/C microstructures for optimal design and fabrication. The peridynamic theory unifies the mechanics of continuous and discontinuous media. It is a continuum approach without spatial derivatives, thus without mathematical singularities. It restores nonlocal interactions and introduces an internal length parameter (horizon of a point) which links different length scales. Because of these features, it enables autonomous multiple damage initiation sites and their complex interactions at unspecified locations along unguided paths. The numerical results concern damage initiation and growth in a complex 3D C/C microstructure. A repeating representative volume element (RVE) composed of yarns and surrounding matrix is constructed according to the periodic architecture of the 3D woven C/C composites. The analysis is conducted through a mixed implicit-explicit algorithm with GPU parallel computing. The strength properties of the constituents are used to determine the critical stretch for damage initiation and growth in the microstructure. The isolated initial micro cracks start merging as the load increases. Subsequently, the crack front reaches to the surface of a nearby fiber. However, the micro-crack cannot pass through that fiber directly. Instead, it deflects along the fiber direction and starts climbing up around the fiber lateral surface.ERDOGAN MADENCI
COMPARISON OF MICROMECHANICS THEORIES FOR MODELING DISCONTINUOUS LONG FIBER REINFORCED COMPOSITES
Authors: PINEDA EVAN J. , KALEEL IBRAHIM , BEDNARCYK BRETT A. , MILLER SANDI G.
Published: November 2023

Two micromechanics theories, the high fidelity generalized method of cells and Carrera Unified Formulation, are used to model a repeating unit cell of a discrete long fiber composite. The models are used to predict the effective properties of a single fiber with varying fiber-to-fiber end gap lengths, as well as the local stresses in the fiber and matrix. Both models produced similar results and demonstrated that they could capture the complex local load transfer due to the shear lag effect.
ASSESSING DAMAGE IN COMPOSITES WITH ACOUSTO-ULTRASONICS AND MACHINE LEARNING
Authors: BADABAGNI SAI THARUN , TALREJA RAMESH
Published: November 2023

This work presents an approach to assessing the severity of damage consisting of delamination emanating from transverse cracks using features of ultrasonic waves and machine learning tools. Matrix cracking and delamination are two commonly observed damage mechanisms in composite laminates. Assessing the severity of these damage modes during service is important for structural safety. Structural health monitoring (SHM) methods are commonly concerned with detecting the location and extent of damage but do not provide quantitative measures to evaluate the ability of structures for continued safe operation. Ultrasonic waves based SHM methods, known as acousto-ultrasonics (AU), have shown great potential for in-field material inspections due to their ease of execution with simple portable sensors and their sensitivity toward damage. The transmitted waves in AU interact with damage, producing complex displacement patterns that cause alterations in the signals at the receiving sensor. The current work aims to utilize the features of those received wave signals to establish correlative relationships between them and the severity of damage for complex damage cases observed in composite laminates. The features extracted from the wave signals may not always provide direct and unambiguous measures reflecting the damage state, making it difficult to assess damage with a single signal. However, the advances in machine learning and pattern recognition make it possible to optimize the feature selection process, eliminating the need to inspect individual signal features. In this work, data from the finite element simulations of various realizations of delamination emanating from transverse cracks are used in machine learning models. It is found that these models successfully identify the signal features that correlate with the damage for the random test cases used and thereby give an excellent prediction tool to assess the damage severity.
EFFECT OF GRAPHENE QUANTUM DOTS ON THE MECHANICAL PROPERTIES OF BISPHENOL F-BASED EPOXY
Authors: DESHPANDE PRATHAMESH P. , KELES OZGUR
Published: November 2023

Nanofillers have gained popularity in the composites industry to enhance the already desirable thermo-mechanical properties of the material. These fillers have been reported to generate poor bonding, agglomeration, void-formation, and similar nano-scale defects. Graphene Quantum dots (GQDs) are one of the smallest nanofiller with a diameter of ~1 nm that can mitigate the commonly seen defects in toughened composites. Molecular Dynamics (MD) is used to investigate the molecular mechanisms generated by embedding a single GQD in an epoxy matrix. Mechanical characterization of a single pristine GQD-epoxy system is reported in this study.
Genologia w lingwistyce – lingwistyka w genologii
Authors: Wojtak Maria
Published: November 2023

GENOLOGY IN LINGUISTICS – LINGUISTICS IN GENOLOGY
The author draws a sketch picture of genology from two perspectives outlined in the title. Linguistic genology is considered as the form of presence of genology in linguistics. It’s being developed since the 1990s by a large group of linguists and treated as a sub-discipline, usually combined with textology, stylistics, pragmalinguistics and axiolinguistics. The article discusses the basic methodological assumptions of the sub-discipline, its organization and scopes, as well as results of the research.The second part of the article is dedicated to the author’s original proposal of interpreting genology as an open cognitive space, filled with various thought styles as understood by Fleck. It allows for combination of linguistic approaches preserved in the tradition with a wide range of authors’ original research proposals in the form research programs etc. in order to give genology the character of cognitive paths of humanistic nature merged in various ways.
Odproprialny czy odapelatywny? – problemy opisu motywacji związków frazeologicznych z nazwą własną
Authors: Kosek Iwona
Published: November 2023

FROM A PROPER NOUN OR FROM A COMMON NOUN? ON SOME PROBLEMS IN THE MOTIVATION OF PHRASEOLOGICAL UNITS WITH PROPER NAMES
The paper addresses the issue of the motivation of some phraseologisms which include components homonymous with proper names (e.g., dookoła wojtek, lit. ‘Wojtek in circles’; w koło macieju, lit.‘Maciej in circles’, both these idioms meaning ‘to keep talking or doing the same thing all the time’; bosy antek, lit. ‘barefoot Antek’, referring to a person from central Poland, historically under Russian occupation; cienki bolek, lit. ‘thin Bolek’ meaning a person who is weak and incompetent). The aim of the study is to indicate some difficulties in an analysis of the origin of such units, which illustrates more general problems in the description of their motivation. In the discussed expressions, the original source of their nominal components remains unclear, which distinguishes them from such unitsas Achilles heel, the shirt of Nessus. The problems identified in the analysis relate to the phenomenon of apelativisation of proper nouns, which is part of the broader issue of the relationship between phraseologism and proper nouns.
Amatorskie promowanie gwary cieszyńskiej (wybrane formy, strategie, rozwiązania)
Authors: Bortliczek Małgorzata , Bogoczová Irena
Published: November 2023

AMATEUR PROMOTION OF THE CIESZYN DIALECT (SELECTED FORMS, STRATEGIES, SOLUTIONS)
The paper focuses on the dialectological topics and problems related to sociolinguistics, ethnolinguistics and psycholinguistics. It gives us insight into Cieszyn Silesia’s linguistic situation, especially in the Czech part of Zaolzie. It presents four social and individual activities, which aim to promote, support, and even revive Cieszyn dialect. The authors describe respectively: 1) testing knowledge of the dialect in form of quizzes, 2) promotion of the dialect across musical texts, 3) encouraging children and young people to use the dialect in a dialect contest, and 4) recording amateur vlogs, which are to enhance internet users’ language and national awareness. Internet and authors’ own remarks related to the official and unofficial social events are the sources of the language materials used in this analysis. Language and cultural development in society – as it is well known – heads toward unification that is increasingly difficult to resist effectively. The subjects responsible for promoting the dialect are eager to maintain the territorial dialect of the national language for future generations. Although they sometimes do it unprofessionally, linguists should be interested respectively in their efforts.