bluuebunny/crossref_metadata_2025 huggingface dataset:
Intrusion Detection System Using the G-ABC with Deep Neural Network in Cloud Environment
Authors: Gulia Nishika , Solanki Kamna , Dalal Sandeep , Dhankhar Amita , Dahiya Omdev , Salmaan N. Ummal
Published: April 2023

Cloud computing plays a pivotal role in sharing resources and information. It is challenging to secure cloud services from different intruders. Intrusion detection system (IDS) plays a vital role in detecting intruder attacks, and it is also used to monitor the traffic in the network. The paper is aimed to control the attacks using the machine learning (ML) technique integrated with the artificial bee colony (ABC) named Group-ABC (G-ABC). The IDS detector has been implemented and further simulation results have been determined using the G-ABC. The evaluation has been carried out using the measures such as precision, recall, accuracy, and F-measure. Different attacks such as user to root (U2R), probe, root to local (R2L), backdoors, worms, and denial-of-service (DoS) attacks have been detected. The simulation analysis is performed using two datasets, namely, the NSL-KDD dataset and UNSW-NB15 dataset, and comparative analysis is performed against the existing work to prove the effectiveness of the proposed IDS. The objective of the work is to determine the intruder attacker system using the deep learning technique.
A Model of Basement Membrane-Associated Gene Signature Predicts Liver Hepatocellular Carcinoma Response to Immune Checkpoint Inhibitors
Authors: Shen Jiajia , Wei Zhihong , Lv Lizhi , He Jingxiong , Du Suming , Wang Fang , Wang Ye , Ni Lin , Zhang Xiaojin , Pan Fan
Published: April 2023

Liver hepatocellular carcinoma (LIHC) is a highly lethal malignant tumor originating from the digestive system, which is a serious threat to human health. In recent years, immunotherapy has shown significant therapeutic effects in the treatment of LIHC, but only for a minority of patients. The basement membrane (BM) plays an important role in the occurrence and development of tumors, including LIHC. Therefore, this study is aimed at establishing a risk score model based on basement membrane-related genes (BMRGs) to predict patient prognosis and response to immunotherapy. First, we defined three patterns of BMRG modification (C1, C2, and C3) by consensus clustering of BMRG sets and LIHC transcriptome data obtained from public databases. Survival analysis showed that patients in the C2 group had a better prognosis, and Gene Set Variation Analysis (GSVA) revealed that the statistically significant pathways were mainly enriched in the C2 group. Moreover, we performed Weighted Correlation Network Analysis (WGCNA) on the above three subgroups and obtained 179 intersecting genes. We further applied function enrichment analyses, and the results demonstrated that they were mainly enriched in metabolism-related pathways. Furthermore, we conducted the LASSO regression analysis and obtained 4 BMRGs (MPV17, GNB1, DHX34, and MAFG) that were significantly related to the prognosis of LIHC patients. We further constructed a prognostic risk score model based on the above genes, which was verified to have good predictive performance for LIHC prognosis. In addition, we analyzed the correlation between the risk score and the tumor immune microenvironment (TIM), and the results showed that the high-risk scoring group tended to be in an immunosuppressed status. Finally, we investigated the relationship between the risk score and LIHC immune function. The results demonstrated that the risk score was closely related to the expression levels of multiple immune checkpoints. Patients in the low-risk group had significantly higher IPS scores, and patients in the high-risk group had lower immune escape and TIDE score. In conclusion, we established a novel risk model based on BMRGs, which may serve as a biomarker for prognosis and immunotherapy in LIHC.
Bioefficacy and Safety Assessment of Protein Isolates Obtained from Nonconventional Sources
Authors: Sibt-e-Abbas Muhammad , Sadiq Butt Masood , Saeeduddin Muhammad , Taferra Tadesse Fikre , Ahmad Shabbir
Published: April 2023

Nonconventional protein isolates were prepared from defatted oilseeds (sesame, flaxseed, and canola). Bioevaluation was performed via growth study parameters i.e., protein efficiency ratio (PER), net protein ratio (NPR), and relative net protein ratio (RNPR). The highest values for these parameters were recorded in sesame protein isolates (SPIs) followed by canola protein isolates (CPIs) and flaxseed protein isolates (FPIs). Nitrogen balance study parameters represented maximum true digestibility (TD) in SPI trailed by FPI and CPI. However, biological value (BV) was found higher in FPI. Similarly, the highest value for net protein utilization (NPU) was noticed in FPI tracked by SPI and CPI. Moreover, safety assessment of protein isolates was also performed including serum protein and kidney and liver function tests. All these parameters showed nonsignificant variations among the tested protein isolates. The outcomes of research explicated that these protein isolates can play a pivotal role to increase the protein level of individuals.
Experimental Implementation of Cascaded H-Bridge Multilevel Inverter with an Improved Reliability for Solar PV Applications
Authors: Dhanamjayulu C. , Girijaprasanna T.
Published: April 2023

This study presents the boost converter-based cascaded H-bridge (CHB) multilevel inverter with improved reliability for solar PV (photovoltaic) applications. The solar PV is associated with the boost converter to enhance DC link voltage by using the maximum power point tracking-perturb and observe (MPPT-P & O) technique. The proposed configuration is aimed toward the performance analysis of the boost converter-based CHB MLI by reducing the number of components, low total harmonic distortion (THD), reduced power, less cost function, low total standing voltage (TSV), improved reliability, and switching losses for solar PV application. In this study, a CHB multilevel inverter is used to obtain stepped pure sinusoidal AC from the solar PV array. The proposed boost converter extracts maximum power and enhances higher DC link voltage which provides high efficiency. The boost converter is integrated with a 27-level CHB multilevel inverter to generate near-sinusoidal output voltage with lower THD. The inverter is tested with linear and nonlinear loads for robustness, and during dynamic loads, inverter is stable and well suited to grid-connected applications. A detailed comparison is presented on the component count and reliability aspects with existing MLIs and 27-level MLIs. The simulation outcomes of the implemented arrangement are presented with the help of MATLAB/Simulink, an experimental prototype is developed using a dSPACE RTI1104 controller and also tested in the research laboratory for checking the possibility of the implemented arrangement.
Resilience Evaluation of Ports along the Maritime Silk Road from the Perspective of Investment and Construction
Authors: Lin Weishan , Liu Wei
Published: April 2023

Since the establishment of the “Belt and Road” initiative, the investment and construction of ports along the 21st Century Maritime Silk Road have received extensive attention from the international community. The evaluation of ports is of great significance to investors’ investments and construction of ports around the world, so it is very necessary to establish a reasonable port evaluation system. At present, there are few studies on defining and evaluating port resilience, and the existing port evaluation index system has defects. Therefore, according to the similarity between cities and ports, this paper introduces the concept of “three-dimensional space” and the “system of systems” theory of cities and divides the resilience of ports along the Maritime Silk Road into three-dimensional spaces of “physical-society-information.” The CRITIC-entropy method and the TOPSIS method constructed a port resilience evaluation model along the Maritime Silk Road and quantitatively evaluated and analyzed the comprehensive resilience and subspatial resilience of 28 ports along the 21st Century Maritime Silk Road. The results show that the route network port degree, the annual throughput of the port container, and the number of fixed broadband subscribers per 100 people are the key indicators that affect the port’s physical space resilience, social space resilience, and information space resilience. Also, coordinated physical, social, and information spatial resilience development plays a catalytic role in improving overall resilience. Therefore, the investment of ports along the Maritime Silk Road should adopt corresponding and more targeted investment plans according to the actual resilience of each port. The research provides new ideas and directions for investors to invest in port construction and has certain practical guiding significance for the increase of investors’ income and the sound development of the national economy.
Data from Distinct Cell Adhesion Signature Defines Glioblastoma Myeloid-Derived Suppressor Cell Subsets
Authors: Bayik Defne , Bartels Cynthia F. , Lovrenert Katreya , Watson Dionysios C. , Zhang Duo , Kay Kristen , Lee Juyeun , Lauko Adam , Johnson Sadie , Lo Alice , Silver Daniel J. , McGraw Mary , Grabowski Matthew , Mohammadi Alireza M. , Veglia Filippo , Fan Yi , Vogelbaum Michael A. , Scacheri Peter , Lathia Justin D.
Published: April 2023

Abstract
In multiple types of cancer, an increased frequency in myeloid-derived suppressor cells (MDSC) is associated with worse outcomes and poor therapeutic response. In the glioblastoma (GBM) microenvironment, monocytic (m) MDSCs represent the predominant subset. However, the molecular basis of mMDSC enrichment in the tumor microenvironment compared with granulocytic (g) MDSCs has yet to be determined. Here we performed the first broad epigenetic profiling of MDSC subsets to define underlying cell-intrinsic differences in behavior and found that enhanced gene accessibility of cell adhesion programs in mMDSCs is linked to their tumor-accelerating ability in GBM models upon adoptive transfer. Mouse and human mMDSCs expressed higher levels of integrin β1 and dipeptidyl peptidase-4 (DPP-4) compared with gMDSCs as part of an enhanced cell adhesion signature. Integrin β1 blockade abrogated the tumor-promoting phenotype of mMDSCs and altered the immune profile in the tumor microenvironment, whereas treatment with a DPP-4 inhibitor extended survival in preclinical GBM models. Targeting DPP-4 in mMDSCs reduced pERK signaling and their migration towards tumor cells. These findings uncover a fundamental difference in the molecular basis of MDSC subsets and suggest that integrin β1 and DPP-4 represent putative immunotherapy targets to attenuate myeloid cell-driven immune suppression in GBM.
Significance:
Epigenetic profiling uncovers cell adhesion programming as a regulator of the tumor-promoting functions of monocytic myeloid-derived suppressor cells in glioblastoma, identifying therapeutic targets that modulate the immune response and suppress tumor growth.
Time to Introduce Nerve Density in Cancer Histopathologic Assessment
Authors: Hondermarck Hubert , Jiang Chen Chen
Published: April 2023

The density of nerves in the tumor microenvironment is increasingly reported to be associated with worse clinical outcome in various cancers. Therefore, it is time to consider the assessment of nerve density in clinical cancer pathology, and interestingly, the development of artificial intelligence may facilitate this clinical translation.

See related article by Perez-Pacheco et al., p. 2501
Sex Differences in Cardiac Troponin Trajectories Over the Life Course
Authors: de Bakker Marie , Anand Atul , Shipley Martin , Fujisawa Takeshi , Shah Anoop S.V. , Kardys Isabella , Boersma Eric , Brunner Eric J. , Mills Nicholas L. , Kimenai Dorien M.
Published: April 2023

Background:

Cardiac troponin concentrations are lower in women than men. We examined whether age- and risk factor-related changes in cardiac troponin over the life course differ by sex and if the trajectory of cardiac troponin was informative in respect of cardiovascular outcomes in women and men in the general population.

Methods:

In the Whitehall II cohort, high-sensitivity cardiac troponin I concentrations were measured on 3 occasions over a 15-year period. Using linear mixed-effects models, the sex-specific trajectories of cardiac troponin were evaluated, and the relationship with conventional cardiovascular risk factors determined. Using multistate joint models, the association between sex-specific trajectories of cardiac troponin and a composite outcome of nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death was evaluated.

Results:

In 2142 women and 5151 men (mean, 58±7 and 57±7 years of age, respectively), there were 177 (8.3%) and 520 (10.1%) outcome events, respectively, during a median follow-up of 20.9 (25th to 75th percentile, 15.8–21.3) years. Cardiac troponin concentrations were persistently lower in women than in men (median baseline concentration: 2.4 [25th to 75th percentile, 1.7–3.6] ng/L versus 3.7 [25th to 75th percentile, 2.6–5.8] ng/L, respectively,
P
<0.001), with women exhibiting a relatively larger increase with advancing age as compared with men (
P

interaction

<0.001). Apart from age, a significant and divergent interaction with sex was found for the association between cardiac troponin and body mass index (BMI) (
P

interaction

=0.008) and diabetes (
P

interaction

=0.003). During follow-up, cardiac troponin concentrations were associated to the outcome in both women and men (adjusted hazard ratio per 2-fold difference [95% CI, 1.34 (1.17–1.52) and 1.30 (1.21–1.40), respectively],
P

interaction

=
0.752). The slope of cardiac troponin was significantly associated with the outcome in women, but not in men (adjusted hazard ratio [95% CI, 2.70 (1.01–7.33) and 1.31 (0.62–2.75), respectively],
P

interaction

=
0.250).

Conclusions:

Trajectories of cardiac troponin differ between women and men in the general population, with differing associations to conventional risk factors and cardiovascular outcomes. Our findings highlight the importance of a sex-specific approach when serial cardiac troponin testing is applied for cardiovascular risk prediction.
Paternal Filiation in Muslim-Majority Environments: A Comparative Look at the Interpretive Practice of Positive Islamic Law in Indonesia, Egypt, and Morocco
Authors: Dupret Baudouin , Belkadi Adam , Lindbekk Monika , Yakin Ayang Utriza
Published: April 2023

In most Muslim-majority countries, Islamic normativity underwent a process of “positivization” completely altering the sense which is made of these norms and the ways through which they are obtained. This article aims to deepen our understanding of this phenomenon through a comparative examination of an issue addressed in classical fiqh, partly legislated in modern statutes and codes, sensitive to the progress of scientific evidentiary methods, and largely at judges’ discretion. It proceeds, for each of the three countries under study (Indonesia, Egypt, and Morocco), to describe the situation, starting with the legal system, family law, and the question of paternal filiation (ithbât al-nasab, in Arabic), then paying attention to the “trajectory” of a recent case, from first-instance decisions to final rulings. In conclusion, it focuses on the room that the combination of fiqh principles and contemporary legal sources and thinking opens for creative analogy, radically innovative interpretation, and polycentric tensions between various jurisdictions.
The morphological diversity of Mymaridae (Hymenoptera): an atlas of scanning electron micrographs. Part 1. General overview and structure of the head
Authors: HUBER JOHN T. , BOLTE KLAUS , READ JENNIFER D.
Published: April 2023

This is the first in a series of studies that aim to provide a comprehensive overview of the morphological diversity of Mymaridae (Hymenoptera), a monophyletic family of small parasitic wasps that are postulated as the sister group of other Chalcidoidea. The external cranial morphology of 65–75 genera and subgenera of Mymaridae (fairyflies) is described and illustrated with almost 430 scanning electron micrographs, including 73 micrographs of the anterior, 68 of the posterior, 75 of the dorsal, 75 of the lateral, and 67 of the ventral views of the head, plus 71 micrographs of the ventral view of the mouthparts. Twenty-one annotated figures illustrate the terms used for morphological structures. Two appendices list the 64 morphological terms and 5 measurements that are defined and illustrated, and the 116 currently recognized valid genera and subgenera of Mymaridae, including collection localities for those that are illustrated. Discussion of head morphology characteristic of Mymaridae is preceded by an overview that includes discussion of best practices for taxonomic descriptions and why these and accurate identifications require well preserved and imaged specimens. Aspects of intraspecific variation, colour, secondary sexual dimorphism, setation (chaetotaxy), surface sculpture and morphometrics are also treated as all of these are often important for describing and distinguishing species. Many of the features illustrated have not previously been used in Mymaridae systematics but may prove to be useful for helping to identify and describe genera and species.
Magnetohydrodynamic (MHD) Natural Convection Flow of Titanium Dioxide Nanofluid Inside 3D Cavity Containing a Hot Block: Comparative with 2D Cavity
Authors: Moderres Mourad , Boutra Abdelkader , Kherroubi Seddik , Oztop Hakan F. , Benkahla Youb Khaled
Published: April 2023

The natural convection of TiO2-Water-Nanofluid in a cubic cavity, containing a hot block under the influence of the magnetic field was studied numerically. The verticals walls are cold, the bottom wall is hot and the other walls (top, front and rear) are adiabatic. This work
aims to visualize the importance of taking into account the three-dimensionality of the flow in the presence of magnetic field as well as the impact of the addition of nanoparticles on heat exchange rate evolution. The governing equations are solved using the finite volume method and the SIMPLER
algorithm is used for pressure-velocity coupling. The problem was simulated at different Rayleigh numbers (103 ≤ Ra ≤ 106), Hartmann numbers (0 ≤ Ha ≤ 90) and inclination angles of the magnetic field (0 ≤ ω ≤ 135°) as well
as nanoparticles volume fraction (φ = 0%, φ = 5%) with fixed Prandtl number (Pr = 7). The thermal conductivity and dynamic viscosity of the nanofluid are estimated by taking into account temperature-dependent properties, using Corcione’s correlations. Based
on the cooling optimization of cold walls along with comparative analysis between 3D cavity and 2D cavity, the obtained results show that the buoyancy force enhances the heat exchange, while the magnetic field produces opposite effects. When the buoyancy force is dominated, the intensification
of heat transfer becomes large, compared to the case where conduction is dominant. The qualitative difference between a 3D and 2D configuration is remarkable for higher Ra, and becomes smaller when the magnetic field is applied horizontally or vertically with relatively high intensity. But,
quantitatively, the 3D flow is far from being considered as a 2D flow for all pertinent parameters control. Finally, adding nanoparticles enhances heat transfer for both configurations, the best transfer rate is obtained for ω = 0.
Computational Simulation of Unsteady Squeezing Hybrid Nanofluid Flow Through a Horizontal Channel Comprised of Metallic Nanoparticles
Authors: Murtaza Saqib , Kumam Poom , Ahmad Zubair , Ramzan Muhammad , Ali Ibne , Saeed Anwar
Published: April 2023

The characteristics of hybrid nanofluid flow contained copper (Cu) and cobalt ferrite (CoFe2O4) nanoparticles (NPs) across a squeezing plate have been computationally evaluated in the present report. In biomedical fields, in very rare cases fluid flow through a
static channel. Similarly in industrial sights, we are also often observed that the fluid flows through comprising plates rather than fixed plates (flow in vehicle’s engine between nozzles and piston). CoFe2O4 and Cu nanoparticles are receiving huge attention in
medical and technical research due to their broad range of applications. For this purpose, the phenomena have been expressed in the form of the system of PDEs with the additional effect of suction/injection, heat source, chemical reaction, and magnetic field. The system of PDEs is simplified
to the dimensionless set of ODEs through similarity replacements. Which further deals with the computational approach parametric continuation method. For the validity and accuracy of the outcomes, the results are confirmed with the existing works. The results are displayed and evaluated through
Figures. It is detected that the hybrid nanoliquid has a greater ability for the velocity and energy conveyance rate as related to the nanofluid. Furthermore, the energy profile declines with the consequences of unsteady squeezing term, while enhances with the effects of suction factor, heat
absorption and generation, and lower plate stretching sheet.
Northward Shifts of the Sahara Desert in Response to Twenty-First-Century Climate Change
Authors: Tian Chuyin , Huang Guohe , Lu Chen , Song Tangnyu , Wu Yinghui , Duan Ruixin
Published: April 2023

The spatial extent of the Sahara (the largest nonpolar desert) has significant impacts on the livelihood of people residing in its surrounding areas. Despite the fact that climate change would foreseeably impact the location and size of the desert, its future responses (i.e., advance or retreat) are rarely explored in previous studies. Here, through the development of an ensemble Bayesian discriminant analysis approach, we use 10 of the latest high-resolution GCM (global climate model) simulations to document robust annual and seasonal responses of the Sahara Desert to twenty-first-century climate change, with the consideration of modeling uncertainties. We find northward shifts of the Sahara/Sahel and eastern expansion of the nondesert zone under both SSP2–4.5 and SSP5–8.5 scenarios, the former more pronounced in the wet season and the latter in the dry season. Countries located near the Mediterranean may thus experience higher risks of drought, while the projected retreat of the Saharan southern boundary will be beneficial to the local water availability of proximal countries.

Significance Statement

Given that sub-Saharan Africa is one of the most vulnerable regions to climate change, the Sahara’s expansion would bring unexpected health risks to billions of people. It is thus vital to understand its robust response to global warming. However, previous studies are merely focused on using a simple precipitation threshold as the definition criterion to estimate the varying size of the Sahara Desert. In addition, significant uncertainty in precipitation projections also limits relevant investigations of the Sahara’s future responses. Here, by developing an ensemble Bayesian discriminant analysis approach, we could provide an objective basis for desert identification under large intermodel uncertainty. Further, we find significant northward shifts of both the Sahara and the Sahel, which may induce higher risks of drought over the northwest of North Africa.
Suicides among adults in Paraguay: An 18-year national exploratory study (2004–2022)
Authors: Torales Julio , Barrios Iván , Melgarejo Osvaldo , Tullo-Gómez Juan Edgar , Díaz Noelia Ruiz , O’Higgins Marcelo , Maggi Carol , Adorno Víctor , Medina Alicia , Villalba-Arias Jorge , González-Urbieta Israel , Caycho-Rodríguez Tomás , Castaldelli-Maia João Mauricio , Ventriglio Antonio
Published: April 2023

Background:

The number of suicides has been increasing worldwide, year after year, becoming the fourth leading cause of death among young people between 15 and 29 years of age.

Aim:

In this study, we explored the frequency and characteristics of suicides among the adult general population in Paraguay between 2004 and 2022, considering that suicide attempts and suicidal risk/ideation are frequent and relevant issues in the consultation activity, even if epidemiological evidence on the national rates of suicide is scarce.

Methods:

In this observational, descriptive, and exploratory study, official records of all deaths by suicide were reviewed and information analyzed. In addition, an attempt was made to predict the number of suicides in the next 5 years according to a mathematical modeling.

Results:

In the 18-year period, 5,527 suicides of adults were recorded. Patients’ mean age was 36.8 ± 17 years old. A 76.77% of them were males, 77.44% were from an urban area and 25.98% from the Greater Asunción and Central Department of Paraguay. The most frequently used method of suicide was intentional self-inflicted injury by hanging, strangulation, or suffocation (all 67.6%). The expected number of national suicides in the following years from 2023 to 2027 will range between 462 and 530. Limitations include the lack of information regarding diagnoses and personal history in the suicide reports as well as the possibility of underreporting of national suicide cases.

Conclusion:

Our results represent the first large national epidemiological report of suicides in Paraguay and may be of interest for mental health professionals and health authorities in order to reduce the suicide mortality rate within the country.
Asymmetric burden-sharing and the restraining and deterrence effects of alliances
Authors: Iwanami Yukari
Published: April 2023

Alliances are often presumed to serve the dual purpose of restraint and deterrence, though few existing studies examine their relationship and the connection with defense burden-sharing. This research employs a three-player game-theoretic model, which endogenizes the process of alliance formation and arms buildups, to demonstrate how intra-alliance burden-sharing allows the alliance to preserve the status quo. The results suggest that alliance burden-sharing may exert the deterrence and restraining effects, while at most one effect is observable at a time because the effects occur in separate parameter spaces. If a prospective ally’s cost of arms buildups is relatively low, a status-quo-oriented superpower may form an alliance even by shouldering a disproportionately heavy burden to dissuade the ally from overturning the status quo ( the restraining effect). Conversely, if the cost is relatively high, the superpower may form an alliance to protect the ally from external threats ( the deterrence effect). However, to prevent being exploited by this ally, the superpower provides only the units of armed forces that are sufficient to incentivize the ally to bolster its military capabilities to deter the threats. Their alliance entails power aggrandizement, but it does not provoke a non-signatory as the ally remains too weak to act unilaterally.
Making Futures by Freezing Life: Ambivalent Temporalities of Cryopreservation Practices
Authors: Braun Veit , Lafuente-Funes Sara , Lemke Thomas , Liburkina Ruzana
Published: April 2023

The preservation of biological matter at extremely low temperatures has gained increasing importance in a broad range of life science fields in recent years. Social and cultural studies of cryotechnologies have often likened the freezing of life to a stillstand of time. This special issue explores the argument that cryotechnologies require us to rethink time and temporality more broadly: freezing does not simply equate to an interruption of the “natural” course of time. Covering diverse types of freezing practices and biological materials—egg cells, cord blood, lab mice, and breast milk—the articles in this issue inquire empirically and theoretically into different ways in which cryotechnologies contribute in making particular pasts, presents, and futures. In engaging with cryopreservation, we have to take into account the complex, sometimes contradictory, pathways in which life, death, and time are made and remade through freezing.
Developmental Networks of Young Adults for Career Growth Opportunities: South Korean Self-Initiated Expatriates in Vietnam
Authors: Oh Seokyoung , Jang-Tucci Kyoungjin
Published: April 2023

This quantitative study examined the characteristics of the developmental networks of young South Korean self-initiated expatriates (SIEs) in Vietnam and the effects of the network characteristics on developmental functions and career growth. Based on a literature review, a hypothesized model was developed and examined using a path analysis. The results demonstrated that organizational, cultural, and program diversity and network strength influenced different types of developmental functions (career, psychosocial, and cultural support). The findings also demonstrated that cultural support did not have a direct relationship with perceived career growth opportunities, while it indirectly influenced career growth through career and psychosocial functions of developmental networks. This study provides a comprehensive understanding of SIEs’ developmental networks and their effect on career development with empirical evidence. The results of this study will inform career counselors and educators on how to support SIEs’ career development and career-related relationship building.
Effects of non-electrical parameters on the characteristics of discharge craters and machining performance in short electrical arc milling
Authors: Wang Bingbing , Zhou Jianping , Chen Xiaokang , Xu Yan , Tang Wei , Qin Caoyang , Ji Yu
Published: April 2023

During electrical discharge machining (EDM), the process parameters greatly influence the discharge characteristics and machining performance, including electrical and non-electrical parameters. As a new EDM method, short electrical arc milling (SEAM) is plagued by frequent short circuits, poor debris removal, and low energy-transfer efficiency. Therefore, this paper investigated the influence of non-electrical parameters (electrode material, working medium, and electrode rotation) on the crater characteristics, machining efficiency, and electrode wear. The micromorphological characteristics of the workpiece were explored. The results suggested that non-electrical parameters compressed and fractured the plasma channels, thus changing the effect of EDM. The air-tap water medium and electrode rotation promoted debris removal and arc breaking, which prevented the arc from ablating the workpiece. When GH4099 alloy was machined with a copper electrode, the workpiece surface quality and machining efficiency were high, and the thickness of the heat-affected zone was small. This work reveals the characteristics of short electric arc discharge and provided a theoretical basis for the efficient and high-quality machining of difficult-to-cut materials by SEAM.
Secondary air induced flow structures and mixing in a fixed bed combustor
Authors: Junejo Awais , Chapela Sergio , Porteiro Jacobo , Al-Abdeli Yasir M
Published: April 2023

Air staging features widely in biomass combustion from small space heaters to industrial-scale moving grate systems. Whilst studies have been conducted into the impact of air staging on emissions and combustion performance, there is little or no insight into the exact flow dynamic and physical mechanisms that are induced by secondary air under such conditions. This paper uses experimental data to validate numerical predictions before investigating the flow field structures and mixing characteristics in a fixed bed air staged combustor. The study utilizes Constant Temperature Anemometry (CTA) experiments to establish boundary conditions for a lab-scale fixed bed combustor. Results from numerical simulations obtained using [Formula: see text] l- 𝜔 model were in good agreement with experimental data. Conditions tested cover five different secondary to total air ratios (Qs/Qt) and two different locations of secondary air injection. Results show that at Qs/Qt = 0.50, 0.25 and 0.18 one strong recirculation zone is induced upstream of the secondary air injection and one downstream. Varying the point of injection of secondary air from h/D = 0.64 to h/D = 0.40 also had an effect on the size of the upstream recirculation zone. Qs/Qt = 0.50 had the highest values of mixing index among all spatially located planes at the upstream of secondary air injection. The overall findings shed light on the possible flow interactions between secondary air and the top layers of fuel bed. They also highlight the significance of secondary air on inducing both upstream and downstream flow structures.
Vibration characteristics of a functionally graded polymer nanocomposite shaft-disk rotor reinforced with graphene nanoplatelets
Authors: Cai Yi , Liu Zi Feng , Gu Junjie , Fu Yan Ming , Zhao Tian Yu
Published: April 2023

In this paper, a rotating functionally graded (FG) polymer nanocomposite shaft-disk assembly reinforced with graphene nanoplatelets (GPLs) resting on elastic supports is modelled and its vibration behaviours are analysed. The effective material properties of the shaft and disk are assumed to vary along their radius directions and determined via the Halpin–Tsai model together with the rule of mixture. Different non-uniform and uniform distributions of GPLs in the rotating assembly are taken into account. In accordance with the finite element (FE) method, the modelling and free vibration analysis of the nanocomposite shaft-disk rotor system is conducted. To verify the present analysis, both the theoretical and experimental methods are employed. A comprehensive parametric study on the effects of the graphene nanoplatelets (GPL) weight fraction, GPL distribution pattern, length-to-thickness ratio and length-to-width ratio of GPLs, shaft length, elastic support stiffness and rotating speed on the free vibration results are investigated, which gives effective ways to achieve improved mechanical performance of a rotating nanocomposite disk-shaft assembly.
The Plane Hydrostatic Test as a Means for Selecting Appropriate Failure Criteria in Fibre Composites
Authors: Theocaris Pericles S.
Published: April 2023

Biaxial tests in anisotropic plates of composite materials do not provide a conclusive evidence for the selection of the appropriate version of the failure tensor polynomial criterion (FTP). On the other hand triaxial tests, which could be decisive, present difficulties and inaccuracies when anisotropic materials should be tested.

It was shown in this paper that a simple biaxial hydrostatic test in the transverse isotropic plane of a transversely isotropic material constitutes an accurate technique to decide which version of the criterion is valid. It was proved that the anisotropy along the strong stress axis of the material increases considerably the differences in failure in the transverse isotropic plane between the various criteria and it constitutes a safe test for deciding the validity of the appropriate criterion. Tests in biaxial hydrostatic tension or compression with different composite materials indicated clearly the superiority of the elliptic paraboloid failure surface criterion (EPFS).
Relation between Weight Changes and Bending Properties of GFRP Panel Immersed in Hot Water
Authors: Morii Tohru , Tanimoto Toshio , Hamada Hiroyuki , Maekawa Zen-ichiro , Hirano Takahiro , Kiyosumi Kenji
Published: April 2023

This study deals with the relation between weight changes and the bending properties of GFRP panels immersed in hot water. The GFRP panels used in this study were three kinds of randomly oriented E-glass fibre continuous strand mat reinforced unsaturated polyester resins. These panels were different in matrix resin and filler content. The water immersion tests were conducted at 80°C and the specimen weight before and after immersion was measured. After water immersion, three point bending tests were performed in order to evaluate the reduction in elastic modulus and strength. Weight changes were evaluated in two ways: the weight gain due to water absorption and the weight loss due to matrix dissolution. The water absorption kinetics was different from the typical Fickian diffusion behaviour, and a great amount of water penetration into the interface was associated with weight loss. Extensive weight loss due to matrix dissolution was caused by degradation at the fibre/matrix interface. The main causes of the modulus and strength reduction of GFRP immersed in water were clarified from the relation between weight changes and bending properties. The elastic modulus decreased with increasing water absorption, and eventually it became constant. The strength decreased linearly with the weight gain due to water absorption. The modulus and strength reductions were caused by the degradation of matrix resin due to water absorption-related processes, such as plasticisation and hydrolysis. However, the modulus reached a constant value in spite of a great amount of water absorption and this was caused by extensive degradation at the interface. The strength reduction observed along with matrix dissolution was caused by the reduction in the load bearing capacity of the fibre following interface breakdown.
Microstructure of Composite Materials Using Small-Angle Neutron Scattering and Contrast Variation: Approaches toward Understanding the Structure of Carbon Black-Elastomer Mixtures
Authors: Hjelm Rex P. , Seeger Philip A. , Wampler Wesley A.
Published: April 2023

Mixed composites of rubber and carbon black are of fundamental importance to rubber technology, and neutron scattering provides a unique view of structure in these interesting and complex systems. This is due, in part, to the nature of the interaction of the neutron with nuclei, which is a function of the specific nucleus, not on atomic number, per se. This allows neutrons to be used to probe fluctuations in chemical and isotopic composition and density in a manner that is a distinct from x-rays or electrons. This aspect of neutron scattering has been used extensively in the study of multicomponent systems, even when components have elements of similar atomic numbers. The large difference in scattering from some isotopes—hydrogen and deuterium being the most important example—can be used to enhance fluctuations in these systems and thus to probe structures that are not accessible by other methods.

We describe the use of small-angle neutron scattering in carbon black, elastomer and carbon black elastomer mixtures using the method of contrast variation. In this approach the sample is suspended in solvents containing different proportions of perdeuterated and protonated molecules. The variation in scattering observed as a function of solvent scattering power gives information on the distribution of components within the sample. Our first experiences using this approach show the potentials of the technique. The use of solvents near the average scattering length density of the carbon black allows observation of non-uniformity in carbon black particles that has not been previously noted. Further, we have established that the shape of the scattering curves in N762 carbon black can be explained as scattering from spherical particles of size and polydispersity measured by electron microscopy. In N121, in which the particle sizes are smaller than N762, contribution to the scatter from the carbon black particle interactions is observable. In gels of solvent extracted carbon black and elastomer we find that the scattering is dominated by carbon black density fluctuations. We find further that the elastomer coats the carbon black particles, at least in N762. There are differences in the association of the carbon blacks in solvent extracted mixtures compared to the carbon blacks suspended in cyclohexane. There may be changes, as well, in the elastomer conformation in the mixtures compared to the polymer alone in cyclohexane. These differences are small in gels containing low concentrations of polyisoprene and carbon black, but are quite profound in a gel containing styrene butadiene rubber with high concentrations of components. Further measurements and modelling of die data will be needed to come to a more satisfactory picture of carbon black morphology and elastomer conformation in the solvent extracted mixtures.
Marine Grade Polyester Resins for Boat Building in the 1990s
Authors: Norwood L.S. , Holton E.C.
Published: April 2023

Long-term evidence strongly supports the suitability of polyester resins for the construction of marine structures. However, misuse and incorrect selection has resulted in some distrust of their use for the manufacture of large structures.

In this paper the issues surrounding the limitations of general purpose resins are discussed and cost-effective alternatives suggested which, if used correctly, can resist blister formation indefinitely. The mechanical performance of these systems is also discussed and compared with vinyl esters, epoxies and toughened resins.

Under cold curing conditions isophthalic acid and isophthalic acid-neopentyl glycol based resins are more than adequate for resisting blister formation for, in some systems, in excess of 20 years at ambient temperatures and with laminate properties matching those of cold cured epoxy or vinyl ester systems.

Examples are given of the effective combination of different resin systems where the main structural laminate is protected by an environmental barrier providing cost-effective structural composites suitable for all marine structures.
The Effect of Mixer Type and Processing Conditions on the Morphology of Polyamide/Polypropylene Blend
Authors: Vainio Tommi P. , Seppälä Jukka V.
Published: April 2023

The effect of mixer type and processing conditions on the morphology of immiscible binary polyamide/polypropylene blend was studied. Blends were prepared in seven different mixers operating at various screw speeds. Changing the screw speed altered the shear stress and mixing intensity applied to the melt, and also the viscosity ratio.

Average panicle sizes of the dispersed phase (PP) and the particle size distributions were determined for extruded and for subsequently injection moulded blends. The number average particle size level achieved in the melt blending was fairly well transferred to the injection moulded blend although the size distribution was broadened after the injection moulding due to the formation of both small (≍1 μm) and large (>10 μm) particles. The morphology of the skin region was very different from that of the core region in both the extruded and the injection moulded blends. The dispersed phase droplet size was dependent on screw speed to some degree. This dependency was greatest for the single screw extruder. Particle size correlated strongly with shear stress, specific mechanical energy input, and mixing intensity of the mixer. Shear stress, we were led to conclude, is a more important factor in controlling the morphology than the shear-rate-dependent viscosity ratio. Mechanical properties of the blends were poor due to weak adhesion at the interface of the blend components. Additionally, we found that melt blending promoted a better and more homogeneous dispersion in the injection moulded blend.
Synthesis and Application of Phosphorylated Glucose in Flame Retardancy Finishing
Authors: Waly A. , El-Aref A.T. , Abdel-Mohdy F.A. , Zamzam N.E. , Hebeish A.
Published: April 2023

An organo-phosphorus compound, namely, phosphorylated glucose (PG) was synthesized. Four chemically modified cottons, namely, carbamoylethylated, acrylamidomethylated, cellulose carbamate, and cyanoethylated cotton bearing comparable amounts of nitrogen were also prepared. The effect of incorporation of PG into a finishing formulation containing Pyrovatex CP and etherified methylolated melamine (EMM) on flame-retardancy and other properties of these modified cottons was studied when the application was carried out under different conditions. The synergistic effect of N/P ratio was thoroughly investigated through an estimation of nitrogen and phosphorus contents and their impact on flame-retardancy properties, crease recovery, tensile strength and elongation at break of the finished cotton products determined.
Detection of Undercure in Carbon-Fibre/Epoxy Composites by Dynamic Mechanical Thermal Analysis
Authors: Akay M. , Cracknell J.G. , Farnham H.A.
Published: April 2023

Desirable properties in thermosetting polymer matrix composites can only be realised after a sufficient degree of matrix curing. It is, thus, important that the state of cure should be clearly identified. Carbon-fibre/epoxy laminates of varying degrees of matrix cure were prepared, and evaluated using static mechanical tests, impact tests and dynamic mechanical thermal analysis. Interlaminar shear and compression tests, although widely used in quality control, were not sufficiently sensitive to distinguish between the cured and significantly undercured laminates. Furthermore, considerable scatter was experienced in the interlaminar shear strength measurements. In contrast, the data obtained from dynamic mechanical analysis were reproducible and indicated more accurately the condition of the materials. Instrumented impact testing also produced relevant information.
Effects of Fibre Treatment on Fibre/Matrix Interfacial Bonding in Pinus Radiata Fibre/Thermoplastic Composites
Authors: Miller N.A. , Stirling C.D. , Van Tilburg V.S.M.
Published: April 2023

The effects of five different chemical treatments of Pin us Radiata fibres, produced by different pulping methods, on interfacial bonding between fibres and polyethylene and polypropylene have been investigated for composites produced by melt blending of fibre and polymer. The effects of adding a proprietary compatibiliser and a maleated polypropylene wax to the blend were also studied. The chemical treatments failed to give any improvement in tensile properties. Untreated fibres on their own and untreated fibres with addition of maleated polypropylene wax gave significant improvement in both tensile strength and stiffness. The lignin content on the surface of the fibres appeared to influence the degree of interfacial bonding in that fibres with low lignin surface content gave better results than fibres with high lignin on the surface.
Cure Kinetics of Epoxy Resin with Styrene Maleic Anhydride Copolymer by Differential Scanning Calorimetry Technique
Authors: Vora Rasikial A. , Trivedi Harikrishna C. , Patel Chandrakant P. , Kazlauciunas Algy , Guthrie J.T. , Trivedi Mukundray C.
Published: April 2023

The curing reactions of an epoxy resin with a styrene-maleic anhydride copolymer were investigated using differential scanning calorimetry at various scan rates (5, 10, 20 and 50°C/min) in a nitrogen atmosphere. The values of certain kinetic parameters, namely activation energy (E), pre-exponential factor (Z), rate constant (k) and half-life (T1/2) were evaluated for various mixtures of a commercial epoxy resin and a styrene maleic anhydride copolymer on the basis of the Ozawa as well as Kissinger methods, which were found to be in reasonably good agreement with each other.
Opto-Thermal Properties of Fibres: 1. Effect of Annealing and Quenching Processes on the Optical Parameters of Courtelle Fibres
Authors: Fouda I.M. , Seisa E.A.
Published: April 2023

The effect of annealing and quenching temperatures, in the range (80–180°C), on various optical parameters has been studied for Courtelle (Courtaulds acrylic fibre) using a Pluta polarizing interference microscope. Relationships between the optical parameters at different temperatures are given for these fibres. The results obtained were utilized for calculations of the isotropic refractive indices and polarizabilities per unit volume, and relationships between these new parameters at different temperatures are given. Also, determinations of Cauchy's constants, dispersive power and the dielectric constant at infinity were carried out. The change in the refractive index profile of the annealed and quenched Courtelle fibres with temperature is given. Illustrations are given using graphs and microinterferograms.