bluuebunny/crossref_metadata_2025 huggingface dataset:
Cracking of Poly(Vinylidene Fluoride) Due to Chemical Attack
Authors: Stirling C.D. , Van Tilburg V.S.M. , Miller N.A.
Published: April 2023

The effects of exposure of poly(vinylidene fluoride) (PVDF) to various chemical solutions has been investigated. Scanning electron microscopy (SEM) was used to examine the exposed samples for signs of chemical attack and cracking, while tensile and flexural bend tests were used to determine the effects of exposure on mechanical properties. Samples exposed to 50% sodium hydroxide exhibited both chemical attack and cracking together with a significant loss in ductility. Exposure to 16% sodium hypochlorite and concentrated sulphuric acid did not give either chemical attack or cracking but exposure to sulphuric acid did cause significant loss of mechanical properties. From the results obtained it was concluded that the cause of cracking in 50% sodium hydroxide was chemical embrittlement, whereby a brittle layer was formed on the surface of the material. This brittle layer subsequently cracked under applied tensile stress. The actual mechanism by which the brittle layer was formed was not established. The cracking was not considered to be due to environmental stress cracking as this requires the simultaneous action of tensile stress and cracking medium.
Interpretation of Disorder and Fractal Dimensions in Transversely Loaded Unidirectional Composites
Authors: Pyrz Ryszard
Published: April 2023

The dispersion patterns of fibres in unidirectional composites are investigated by introducing second-order statistical functions which categorize the patterns of fibre centres as being aggregated, random or orderly. Furthermore these functions allow us to deduce the range of local disorder in the geometrical arrangement of fibres. A series of fracture surface profiles of transversely haded unidirectional composites are analysed in terms of fractal geometry. The fracture profiles are studied from three well-characterized materials having the same constituents but different dispersions of fibres. Fractal properties of fracture profiles are shown to correlate with an appropriate pattern's descriptors, which represent distance-based statistics of fibre distribution.
Structure and Molecular Motions in Crosslinked Isotactic Polypropylene
Authors: de Candia F. , Michele A. , Renzulli A. , Vittoria V. , Chodak I.
Published: April 2023

The structure and the molecular motions of chemically crosslinked iPP samples have been analysed. The samples differ in gel content (i.e. degree of crosslinking). The X-ray analysis shows that two crystalline phases (α and γ) are present, their relative amount depending on the gel content. The thermal analysis suggests that the crosslinked samples are characterized by smaller and more defective crystals. The sample structure (in terms of crystallinity, phase composition and crystal defects) affects the molecular motion phenomena, analysed using the low resolution NMR spectroscopy. In particular, the analysis of the FID (free induction decay) signal shows a complex relationship between temperature, molecular mobility, and phase composition, which agrees with the thermal data.
Design Optimisation of FRP Universal Connectors
Authors: Mosallam Ayman S. , Bedewi Nabih E. , Goldstein Evan
Published: April 2023

There has been an increased demand for developing special connecting elements for pultruded fibre reinforced plastics (PFRP) structures. The first prototype of a moulded fibre reinforced plastic (FRP) universal connector (UC) was presented to the industry in previous work. The merit of this connector was proven through a full-scale testing program for PFRP beam-to-column connections. In order to develop a series of FRP connections with high structural performance and the lowest possible associated cost, design optimisation techniques must be utilised. For this reason, a design optimisation study on a FRP universal connector was conducted. In evaluating the structural performance of each UC design, finite element analysis was employed. The main objective of the study is to develop an optimum design for the UC by maximising its load carrying capacity and minimising the stress concentration at the critical locations. In order to minimize the number of design variables required for producing the optimum UC, the Taguchi statistical method for quality control was incorporated in this study. In this method, statistically planned experiments are used to identify the settings of the UC design parameters that reduce performance variation. Among the different parameters selected in the study are the UC geometry, composite lay-up, and thickness of the various elements comprising the connector. The results of the analysis indicated that the UC wall thickness, the addition of diagonal webs, and the orientation of the fibres in the webs improve the stiffness significantly. Other design recommandations and conclusions are also presented.
Electrical Properties of Solid Insulating Polymers by Thermally Stimulated Discharge Method
Authors: Vaezi-Nejad S.M. , Juhasz C.
Published: April 2023

The electrical phenomena in solid insulating polymers are intimately linked to their physical morphology and microstructure, their temperature and the time at which the observations are made with respect to time at which the stimulus was first applied. In this paper, the authors present a brief account of various transport mechanisms and the methods of investigation. Among several experimental techniques for investigation of electrical conduction, the decay methods, time of flight methods, and contact electrification are briefly described. This is then followed by a detailed description of thermally stimulated discharge technique for investigation of traps, space charges and dipole processes in polymers. In order to illustrate the usefulness of this technique, experimental results will be presented to demonstrate the existence of deep interface hole traps in double layer amorphous semiconductor photoreceptors.
Compressive Strength Retention of Impact-Damaged Laminates Containing Particulate Fillers
Authors: Yang Q. , Pritchard G.
Published: April 2023

The effect of six particulate fillers on the compressive strength of undamaged and damaged glass-epoxy laminates was studied. The intention was to determine whether, and how, the mechanical properties of the filled organic matrix could be correlated with the impact damage tolerance (expressed as compressive strength retention after impact) of fitted epoxy-glass laminates. Impact damage was induced by an instrumented falling weight device. The laminates contained solid glass beads, hollow glass microspheres, quartz, calcium carbonate, alumina trihydrate (ATH) and mica. The test results showed that all the fillers, apart from hollow glass microspheres, increased the tensile and flexural moduli of the fitted epoxy, and this in turn was accompanied by an improvement in the compressive strength of some of the undamaged lominates, but there was no positive correlation between the flexural modulus of the fitted matrix and the impact damage tolerance as reflected in compressive strength retention. In contrast there was a good correlation with matrix strength; i.e. a significant decrease in the compressive strength retention of impact-damaged laminates as the matrix flexural strengths were reduced by adding fillers. The pre-impact interlaminar shear strength of the laminates also correlated well with the compressive strength retention after impact.
Sillicon Compounds as Factors Stimulating the Proliferative-Reparative Function of Connective Tissue and Modifying Reactogenicity of Polymeric Implants
Authors: Slutskii L.I. , Dombrovska L.E. , Sevastjanova N.A. , Shkirmante B.K. , Djakov V.M.
Published: April 2023

Initially, it was found that some representatives of silicon compounds, a new class of silicon organic compounds ‘monocyclic analogs of silatranes, - possess a biological activity which is expressed as a stimulation of the proliferative-reparative function of connective tissue. The. Silicon compounds which were tested accelerated wound healing and epithelisation in rats, they accelerated the evolution of dermal wounds caused by thermal burningas well. When included in the covering of subcutaneously implanted olive-shaped polyethylene devices, silicon compounds effectively stimulated development and maturation of granulation-fibrous capsules surrounding the implants.
The Long Term Mechanical Behaviour of Filled and Unfilled Injection Moulded Thermotropic Liquid Crystalline Polymers
Authors: Plummer Christopher J.G. , Kausch Hans-Henning , Wu Yujun , Gola Muzio
Published: April 2023

Injection mouldings of thermotropic liquid crystalline polymers (TLCPs) have complex, highly anisotropic layered structures, and correspondingly large spatial variations in orientation and mechanical properties. The room temperature axial mechanical properties of standard tensile test specimens moulded from TLCPs are remarkable (ten-fold and two-fold increases in modulus and strength respectively, compared with conventional resins). Nevertheless, in practice glassfibre or mineral fillers are recommended to overcome problems associated with the anisotropy of unfilled TLCP mouldings, such as warping. The resulting reduction of anisotropy and more uniform local properties are not found to compromise seriously the axial mechanical properties, and indeed may improve both the short and the long-term behaviour, depending on the moulding conditions. Short glass-fibre addition appears particularly beneficial for the creep and fatigue resistance.
An Investigation of the Dynamic Response of Continuous Fibre Reinforced Composite Laminates - Failure Morphology
Authors: Li R.K.Y. , Choy C.L. , Duan Zhuping , Zhang Mingqiu
Published: April 2023

By using the split Hopkinson pressure bar technique, impact tests were carried out on fully clamped three-point bending, laminated beam specimens made from continuous glass fibre and carbon fibre reinforced polyphenylene sulphide of three different lay-up sequences. This paper focuses on scanning electron microscope investigations of the impact failure morphology, with the aim of providing a phenomenological background for a new model which can describe the dynamic response behaviour during transverse impact, as well as understanding comprehensively the dominant failure patterns at high strain rate. The results show that the fracture morphology possesses distinct features for each type of laminate, and is a function of both the material characteristics and lay-up sequence. Fibre to matrix adhesion exerts a strong influence on the microcracking mechanism.
Stacking Sequence Effect on Tensile and Fatigue Strength of Symmetric Laminates
Authors: Carroll M. , Ellyin F. , Kujawski D.
Published: April 2023

This paper presents the results of an experimental investigation into the tensile monotonic and fatigue behaviour of symmetric fibreglass-epoxy coupons using three ply angle orientations, 45°, -45° and 0° which were interchanged in three different configurations: [452, -452, 02]s, [452, 02, -452]s and [02, 452, -452]s. The results show that there is significant sequence effect on the monotonic strength and the fatigue performance. The monotonic results demonstrate an increase of 11% in the strength and 6% in stiffness between the weakest laminate, [02, 452, -452]s, and the strongest laminate, [452, -452, 02]s. The fatigue performance depends on lay-up and stress level. At higher stresses, the trend in stacking sequence effect on fatigue strength is the same as for monotonic loading. In contrast, at lower stresses the trend is opposite. The sequence effect observed in the monotonic and fatigue loading is discussed subsequently based on the numerical analysis of interlaminar stresses induced by the free-edge and constraint effect of 0° ply on damage development.
Lap Joint Theory Revisited
Authors: Jones R. , Chiu W.K. , Tomas J. , Trippit B.
Published: April 2023

This paper discusses the stress analysis of adhesively bonded joints and therefore, by analogy, bonded repairs. Attention is focused on the effects of the rate dependence of structural adhesives and it is shown that the use of rate independent solutions to obtain the adhesive shear stresses and shear strains, cannot be said to be generally conservative.
Grafting of Acrylamide to Loomstate Cotton Fabric Using Potassium Permanganate-Thiourea Redox System
Authors: Abdel-Hafiz S.A.
Published: April 2023

Graft polymerisation of acrylamide (Aam) to loomstate cotton fabric using a KMnO4 H2N-C-NH2 system was studied under a variety of conditions. The polymerisation reaction was studied with respect to graft yield, homopolymer total conversion and graft efficiency. Results indicated that the polymerisation reaction was found to depend upon the concentrations of potassium permanganate, thiourea and acrylamide, as well as upon the pH of the reaction medium, reaction time and temperature of polymerisation. Based on detailed investigation of these parameters, the optimal grafting was obtained with 0.04 g/1 kMnO4; 0.06 g/1 thiourea; pH 3; temperature 80°C and time 60 minutes.
The Use of Capillary Rheometry in Predicting Polymer Processing Performance
Authors: von Kemenczky Oliver , Van Buskirk Paul
Published: April 2023

The Theological characterisation of novel polymers is increasingly recognised as vitally important for the prediction and characterisation of processing performance. This paper discusses the use of laboratory scale capillary rheometry and shows that apparent viscosity data at appropriate shear rates correlates well with the behaviour of polymer melts.
The Damage Tolerance of Fire-Retardant Glass-Epoxy Laminates
Authors: Yang Qiang , Pritchard G. , Phipps M.A. , Rose R.G.
Published: April 2023

Alumina trihydrate is an effective and widely used fire retardant and smoke suppressant, with several other incidental advantages, but it usually lowers the mechanical strength of thermosetting resins and laminates. This paper reports the extent of the reduction in the impact damage tolerance of glass-epoxy woven roving laminates, when measured by determining their compression strength retention after impact (CAI). Inserting aramid plies reduced rather than increased the damage tolerance at low impact energies, regardless of their position. Tentative reasons for this observation are offered. Other material changes were also investigated. The benefit of using a rubber toughening modifier (Hycar ATBN) in the epoxy matrix was confined to the lowest impact energy range. Changing the epoxy resin curing agent from a cold curing, mixed amine system to a hot curing piperidine one resulted in an improved compression strength before impact, and in some cases also an improvement in post-impact strength retention.
Phase Behaviour of Blends of poly(chlorinated-ethyl methacrylate) with poly(styrene-co-aciylonitrile) and with poly(p-methylstyrene-co-acrylonitrile)
Authors: Goh S.H. , Lee S.Y. , Low S.M. , Peng Jiande , Ni Xiping
Published: April 2023

The phase behaviour of blends of four poly(chlorinated-ethyl methacrylates) with poly(styrene-co-acrylonitrile) (SAN) and with poly(p-methylstyrene-co-acrylonitrile) (pMSAN) was studied. Poly(1-chloroethyl methacrylate) and poly(2,2-dichloroethyl methacrylate) are miscible with SAN and pMSAN over a certain copolymer composition range, showing miscibility windows. Poly(2,2,2-trichloroethyl methacrylate) (PTCEMA) is miscible with SAN and pMSAN having high acrylonitrile contents, showing miscibility doors. PTCEMA is also miscible with polyacrylonitrile. However, poly(1,2,2,2-tetrachloroethyl methacrylate) is immiscible with any of the SAN and pMSAN samples.
The Influence of Crimp Measurements on the Development and Appraisal of 3D Fully Integrated Woven Structures
Authors: Hill B.J. , McIlhagger R. , Soden J.A. , Hanna J.R.P. , Gillespie E.S.
Published: April 2023

There is a need for an analytical assessment of the properties of 3D woven structures. In this paper a sophisticated method of predicting the proportions of fibre in three mutually perpendicular axes, X (warp), Y (weft) and Z (through-the-thickness), of 3D fully integrated complex woven structures is described. Unlike previous models, this system takes into account in-layer crimp in both the warp and weft directions. The system has been validated against woven fabric structures and regression analysis has predicted a high level of confidence in the results. The method has also been compared with previous methods and has been shown to provide superior results.
Fracture Behaviour of Chopped Glass Strand Reinforced Phenolic Composites
Authors: Gopal P. , Dharani L.R. , Blum Frank D.
Published: April 2023

Modified phenolic composites were fabricated by compression moulding a mixture of chopped glass strands and a cashew nut shell liquid modified phenolic resin. Single edge notched bend (SENB) tests, double edge notched (DEN) tension tests and 3-point flexure tests on unnotched specimens were conducted at various fibre volume fractions and strand lengths. The candidate stress intensity factors of SENB specimens were significantly higher than those of DEN specimens. Glass strand/phenolic interface debonding and strand pull-out were observed for both SENB and DEN specimens. In addition, the DEN specimens exhibited a considerable degree of splitting of glass strands parallel to their axes. By increasing the fibre volume fraction and the strand length, it was possible to improve the flexural strength without adversely affecting the fracture toughness.
Penetration of Aromatic Hydrocarbons into Natural Rubber
Authors: Sombatsompop N. , Christodoulou K.J.
Published: April 2023

An investigation of organic solvents penetrating into and out of natural rubber (NR) vulcanisates as a function of time was conducted with respect to degree of swelling and deswelling, diffusion characteristics and mechanical properties. The natural rubber was vulcanised using different techniques to obtain various types of crosslinking; these included flexible and rigid sulphur, peroxide and mixed linkages. Stress-strain measurement was utilised to determine the overall crosslink density and the mechanical properties of the rubber. The degree of swelling and deswelling was conclusively related to the flexibility and mobility of polymer chains, size of the penetrant, temperature, and desulphuration and decomposition reactions of the crosslinks. Before and after equilibrium swelling overall degree of swelling was affected by the penetrant characteristics, whereas during the equilibrium state the degree of swelling was influenced by the types of crosslinks present in the rubber vulcanisates. The reduction in mechanical properties during swelling was due to the conversion of mechanical energy into an activation energy, this being used to achieve the penetration of the solvents into the polymer network. The property recovery after deswelling involved stress relaxation of the polymer network.
Fire Behaviour of Unsaturated Polyesters
Authors: Mortaigne B. , Baudry A. , Dufay J. , Bourbigot S. , Bras M. Le , Cordellier G.
Published: April 2023

This work is concerned with the fire behaviour of unsaturated polyester resins and particularly with the limiting oxygen index and oxygen consumption data. The influence of styrene level on the rate of heat release is shown. The combustion products of the resins are identified. No change in the nature or proportions of the evolved gases could be detected with different amounts of styrene.
Stress Corrosion Cracking in Fibreglass Composite Structures - A Case Study
Authors: Frankle Robert S.
Published: April 2023

One failure mechanism experienced by fibreglass composite structures is stress corrosion cracking, which occurs in structures under load in a corrosive environment. Over time, stress corrosion cracking attacks the glass fibres, which weakens the structure and can lead to premature failure. Stress corrosion cracking failure is characterized by flat fracture surfaces perpendicular to the fibres at both the macroscopic and microscopic levels. Prevention of stress corrosion cracking includes proper selection of fibre and resin, and use of a protective layer between the glass fibres and the environment. Fibreglass structures that have failed due to stress corrosion cracking include chemical tanks, sewer pipe and pressure vessels.

This paper describes the phenomenon of stress corrosion cracking in fibreglass composite structures. It also presents, as a case study, the investigation of the failure of a fibreglass overwrapped compressed air cylinder, used in a self-contained breathing apparatus. The failure was attributed to stress corrosion cracking following exposure to a highly acidic cleaning fluid.

The cause of the failure was determined based on the results of fractography, chemical analysis, and stress corrosion tests performed on samples of the accident cylinder.
Polymer Foams as Core Materials in Sandwich Laminates (Comparison with Honeycomb)
Authors: Altstädt V. , Diedrichs F. , Lenz T. , Bardenhagen H. , Jarnot D.
Published: April 2023

The mechanical properties of sandwich laminates with two different closed cell polymer foams (PEI and PMI) as core materials were examined compared with sandwich laminates with honeycomb as core material. The applied test methods were compression, tension, four-point bending and instrumented falling weight impact. To examine the influence of the adhesive bonding between the face sheet and the core material, the sandwich laminates were tested with and without adhesive bonding. For comparison purposes the processing procedure for all sandwich laminates was kept constant. Therefore all sandwich laminates were produced at the same time in the same autoclave. In comparison to a honeycomb core, sandwich laminates with foam as core material showed superior surface quality and impact energy absorption. The influence of the adhesive bonding between face sheet and core material was found to be very small under tensile loading conditions. From microscopical investigations of the bond line it was deduced that in the case of direct bonding, sufficient resin was able to flow during processing from the face laminate into the micropores at the foam core surface without adhesive.
Polytetrafluoroethylene-Blended Polyphenylenesulphide Coatings for Mitigating Corrosion of Steel in Geothermal Environments
Authors: Sugama T.
Published: April 2023

To improve the ability of polyphenylenesulphide (PPS) coatings to protect cold-rolled steel against corrosion in a low pH, hypersaline brine geothermal environment at 200°C, polytetrafluoroethylene (PTFE) was blended into the PPS. Not only does PTFE inhibit hot brine-induced oxidation of PPS surfaces, it provides a less susceptible surface to moisture because of its hydrophobic characteristics, reducing the rate of infiltration of corrosive ionic species through the coating film. However, blending an excessive amount of PTFE into PPS creates two undesirable features, causing the failure of the coatings as corrosion-preventingbarriers. One is the development of porous microstructure in the coating layer; the other is the formation of a weak boundary region at the interphase between the blended topcoating and the zinc phosphate precoating. The reason for the latter is the phase separation of PTFE from PPS.
Experimental Investigation of Design Rules for Resin Gating and Venting Using the Vacuum Injection Technique
Authors: Abraham D. , McIlhagger R.
Published: April 2023

Various resin gating methods commonly used for the Resin Transfer Moulding (RTM) method of composite manufacture are discussed, with their associated advantages and disadvantages. Peripheral gating combined with vacuum impregnation was identified from previous studies as being particularly beneficial in achieving complete wet-out and fast injection times. Reported design rules for gating and venting arrangements are also discussed. This investigation has attempted to assess the capabilities of peripheral gating, initially for simple geometrical shapes which then increased in complexity. Existing design guidelines were confirmed and new concepts proposed. RTM processing of the final shape to be considered was finally assessed by comparison of peripheral with rectilinear gating. This process also identified the importance of component design for manufacture and the benefits of peripheral gating. It is hoped that this experimental investigation will not only be useful to RTM mould designers but also to those involved in resin flow modelling of such processes for composite components
The Gunas Personality Framework: Validating a Contemporary Scale
Authors: Sachar Surabhi , Mulla Zubin R. , Krishnan Venkat R.
Published: April 2023

Gunas personality framework is an inclusive and comprehensive personality framework. Every human being is composed of three gunas or fundamental elements —sattva (intelligence-stuff), rajas (energy-stuff), and tamas (mass-stuff). Some of the prior measures of gunas do not fully capture the content of this variable, and some are not suitable for contemporary use. We conceptualize gunas in terms of an individual’s attitude towards social issues and have developed a new measure of gunas. We have demonstrated the concurrent and predictive validity of the measure through a study of two samples of 60 executives and 356 MBA students. We show that sattva predicts performance, rajas predicts effort, and tamas is positively related to dispositional negativity. We show how the new gunas scale is a useful tool in contemporary times.
Vibration isolation performance of a beam clamped with torsional quasi-zero-stiffness isolator
Authors: Tian Yishen , Zhang Xiaoyun , Chen Chao , Fang Bo , Cao Dengqing
Published: April 2023

Elastic beam structures connected by hinges are a common basic component of many mechanical systems. In this study, the nonlinear transverse vibration of a beam with one end free and the other end simply supported with a torsion spring is investigated. A torsional quasi-zero-stiffness vibration isolator is employed at the fixed end of the beam for isolating the vibration excitation from the base. Using Hamilton’s principle, the differential equation of motion for the transverse vibration of the beam is obtained, and the natural characteristics of the beam are determined. The dynamic equation of the system is derived by using Galerkin truncation method and the harmonic balance method is adopted to obtain the nonlinear vibration response. Compared with the vibration transmissibility of the beam supported by the equivalent linear torsion spring, the quasi-zero-stiffness vibration isolation system shows superior vibration isolation performance. It is found that the beam fixed with a torsional quasi-zero-stiffness isolator can reduce the first resonant frequency and provide a wide effective isolation range at low frequency, which is rarely affected by the strong nonlinearity. The results would provide an innovative method of introducing the torsional quasi-zero-stiffness isolator into the passive vibration control of continuum system.
Rating the Honesty of White and Black Children via Implicit and Explicit Measures: Implications for Child Victims in the Criminal Justice System
Authors: O’Connor Alison M. , Hall William , Campbell Karen L.
Published: April 2023

The present study explored implicit and explicit honesty perceptions of White and Black children and whether these perceptions predicted legal decisions in a child abuse case. Participants consisted of 186 younger and 189 older adults from the online Prolific participant pool. Implicit racial bias was measured via a modified Implicit Association Test and explicit perceptions through self-reports. Participants read a simulated legal case where either a Black or White child alleged physical abuse against their sports coach, and they rated the honesty of the child’s testimony and rendered a verdict. Participants were implicitly biased to associate honesty with White children over Black children, and this bias was stronger among older adults. In the legal vignette, for participants who read about a Black child victim, greater implicit racial bias predicted less trust in the child’s testimony and a lower likelihood of convicting the coach of abusing the child. In contrast to their implicit bias, participants self-reported Black children as being more honest than White children, suggesting a divergence in racial attitudes across implicit and explicit measures. Implications for child abuse victims are discussed.
Respite and connection: Autistic adults’ reflections upon nature and well-being during the Covid-19 pandemic
Authors: Friedman Samantha , Noble Roan , Archer Stephanie , Gibson Jenny , Hughes Claire
Published: April 2023

The Covid-19 pandemic and associated lockdowns provided opportunities to engage and reconnect with nature, with many people noting associated benefits to well-being. Research from the pandemic period has largely focused on the way neurotypical or general populations experienced nature; less is known about how autistic people used nature to support well-being during this time. In this qualitative survey study of 127 autistic adults in the United Kingdom, we used reflexive thematic analysis of text box responses to develop two themes: respite in nature and connecting amid widespread disconnection. For some autistic adults during the pandemic, nature provided physical distance from others or from crowded homes, enabling them to use nature to experience relief from stress. In addition, some participants felt more psychologically connected to nature itself during the pandemic, while for others, nature served as a way of connecting with others during a potentially isolating time. These findings have implications for autistic people and their families and carers who may want to seek out nature-based activities to support well-being in the wake of the pandemic.

Lay abstract

The Covid-19 pandemic and associated lockdowns provided opportunities to spend time in nature, with many people reporting that this benefitted their well-being. However, existing research from the pandemic period has focused on the way general populations experienced nature; less is known about how autistic people used nature to support their well-being during the pandemic. We created a survey that invited autistic adults living in the United Kingdom to reply to text box questions. A total of 127 people responded to our survey; we analysed their responses using a method called reflexive thematic analysis and developed themes based on patterns among all the responses. We developed two themes: respite in nature and connecting amid widespread disconnection. For some autistic adults during the pandemic, nature provided physical distance from others or from crowded homes, which helped them reduce their stress. In addition, some participants felt more psychologically connected to nature itself during the pandemic, while for others, nature served as a way of connecting with others during a potentially isolating time. These findings are important for autistic people and their families and carers who may want to seek out nature-based activities to support well-being in the wake of the pandemic.
Commentary on Kögler: Analysing the Ukraine war through a ‘new wars’ perspective
Authors: Kaldor Mary
Published: April 2023

This essay provides supplementary evidence for Kögler’s thesis. It argues that Putin will have ‘won’ if he succeeds in reducing Ukrainian society to a chaotic, fragmented, violent, long-term social condition that can be characterised as a ‘new war’. The essay describes the combination of the ‘political marketplace’ and exclusivist identity politics typical of new wars and how they apply to Putin’s Russia. It concludes with a proposal for negotiations based on principles, especially justice, instead of or as well as borders.
Hand and Wrist Amputation: A Demographic Analysis Using the National Inpatient Sample
Authors: Stearns Stephen A. , Weidman Allan A. , Engmann Toni F. , Valentine Lauren , Hernandez Alvarez Angelica , Foppiani Jose , Lin Samuel J. , Dowlatshahi Sammy
Published: April 2023

Background:

Traumatic hand and wrist amputations are rare but debilitating injuries. Surgical replantation of the hand provides a unique alternative to revision surgery but requires appropriate access to necessary medical resources. This study aims to understand the national practice of replantation of traumatic hand amputation and to determine whether disparities exist in accessing surgical treatment.

Methods:

International Classification of Diseases, 10th Revision codes for replantation and revision amputation surgeries were used to gather data from the National Inpatient Sample from 2016 to 2019. Summary statistics were calculated on demographic, hospital, and outcome variables, with subanalysis performed for effect on replantation and revision rates.

Results:

Seventy-two patients were identified. The average patient was 35 years old with a strong male predominance (90%). The racial distribution of the cohort roughly mirrored the demographic proportions of race in the US population. Fifteen (21%) patients underwent replantation. This rate was similar between sexes, races, and income brackets. Hand replantation was primarily performed at large bed size (87%), private not-for-profit (73%), and urban teaching hospitals (94%). The most common insurance status for these patients was private, followed by Medicaid, Medicare, and self-pay. Forty-seven patients underwent revision amputation (65%) with no association between demographic characteristics. The patients remained hospitalized for significantly longer periods ( P = .0188) and paid significantly more ( P = .0014) if replanted. The patients were most frequently discharged home (65%), followed by skilled nursing facilities (18%).

Conclusion:

This study describes the current state of hand amputation management and finds no evidence of sociodemographic factors influencing the surgical care provided.
Perceptions of teacher leadership in the Arab region: A comparative analysis of three countries
Authors: Hammad Waheed , Sawalhi Rania , Salim Al-Harthi Aisha , Alamri Faisal , Morad Hosam
Published: April 2023

This study compares teachers’ perceptions of teacher leadership in three Arab countries: Qatar, Oman and Egypt. Using the Teacher Leadership Inventory tool, the study examined the factors and demographic variables associated with teacher leadership in the selected countries. Specifically, the study explored the four factors identified by the TLI: Sharing Expertise (SE), Sharing Leadership (SL), Supra-Practitioner (SP), and Principal Selection (PS) and investigated if teachers’ perceptions of these factors would differ based on their country, gender and school type. Three sets of data were collected from the selected countries, and the respondents were teachers working in primary and middle public schools. Means, standard deviations, t-test and one-way ANOVA were used to analyze the data. The results showed the overall level of teacher leadership to be moderate, with Sharing Expertise being the highest ranked factor, followed by Sharing Leadership, Supra-Practitioner and Principal Selection. The study also found both similarities and differences between the three countries. For example, the Qatari sample provided the highest scores on all TLI factors, followed by Egypt and Oman. Differences were also noted based on school type and gender. Implications emerging from the results are discussed and suggestions for improvement are provided.
Twitter-based analysis of anti-refugee discourses in Türkiye
Authors: Yılmaz Fahri , Elmas Tugay , Eröz Betil
Published: April 2023

As the number of refugees in Türkiye continues to grow, the constructed discourse of welcoming refugees with open arms has weakened, transforming the image of refugees from ‘guests’ to ‘threats’. Social media platforms are used to spread hate speech, discrimination, racism, and otherization. Drawing on the Corpus-assisted Critical Discourse Analysis approach, the present research investigates how language is used to produce online discourses in tweets about refugees in the aftermath of a major social triggering event in Türkiye. This mixed-methods study incorporated both a corpus analysis of tweets posted on Twitter over a specific period, as well as a critical discourse analysis of a randomly selected subset of 100 tweets. The findings revealed that the prevalence of discontent and frustration of the host population against refugees has turned into a discourse of discrimination, hate, and racism. Moreover, a negative portrayal of refugees was created and maintained not only through lexical choices, but also characteristics attributed to them, as well as assumptions and prejudices about them.
A multi-view automatic table tennis umpiring framework
Authors: Wong Patrick , Myint Hnin , Dooley Laurence , Hopgood Adrian
Published: April 2023

This paper presents a low-cost, portable, multi-view table tennis umpiring framework, as a viable alternative to the current expensive systems which are almost exclusively restricted to elite professional sports. Table tennis has been selected as the sport to evaluate this framework primarily because it comprises many different complex match elements, including the service, return and rally elements, which are governed by a strict set of regulations which need to be umpired. The aim is to develop novel methods to analyse and judge the legality of such key match facets, with ball detection and tracking in video frames being integral to reliably and accurately determining the ball’s position and flight path during rallies. While a low-cost option is attractive and offers several benefits, it is a technically challenging problem due to the small number and generally low-resolution cameras that are used. A novel multi-view camera setup and multi-agent system (MAS) framework is presented, which comprises computationally lightweight agents which detect and track the table tennis ball, create a 3D representation of the flight path of the ball, predict the ball’s trajectory, and identify and analyse key facets in a table tennis rally. The MAS correctly detects all state transitions in seven test table tennis sequences with minimal latency and while the processing rate of a standard computer may be unable to analyse long rallies in real time, the potential of running the MAS on a parallel architecture is a propitious alternative. The MAS is also scalable, enabling additional camera pairs to be deployed to achieve enhanced accuracy and coverage. The framework affords the potential to reform the way matches are umpired, especially for amateur players, providing an economic and objective manner of dispute resolution, while the multi-view facility is extendible to other relevant ball-based sports. The ball flight path analysis mechanism can be exploited as a valuable training tool for skill development.
Isometric thumb extension exercise as part of a multimodal intervention for de Quervain’s syndrome: A randomised feasibility trial
Authors: McBain Brodwen , Rio Ebonie , Cook Jill , Sanderson Jeffrey , Docking Sean
Published: April 2023

Introduction

de Quervain’s syndrome is a painful condition commonly presented to hand therapists. Exercise is utilised as an intervention, but isometric exercise has not been investigated. We aimed to assess the feasibility and safety of isometric thumb extension exercise for de Quervain’s syndrome and to explore differences between high-load and low-load isometric exercise.

Methods

This parallel-group randomised clinical feasibility trial included individuals with de Quervain’s syndrome. All participants underwent a 2 week washout period where they received an orthosis, education, and range of motion exercises. Eligible participants were then randomised to receive high or low-load isometric thumb extension exercises, performed daily for 4 weeks. Feasibility and safety were assessed by recruitment and drop-out rates, adherence, adverse events, and participant feedback via semi-structured interviews. Secondary outcomes included patient-reported outcomes for pain and function, and blinded assessment of range of motion and strength.

Results

Twenty-eight participants were randomised. There were no drop-outs after randomisation, and no serious adverse events. Adherence to exercise was 86.7%, with 84% of participants stating they would choose to participate again. There were clinically and statistically significant improvements in pain and function over time ( p < 0.001) but not in range of motion or strength. There were no statistically significant between-group differences.

Conclusions

Isometric thumb extension exercise within a multimodal approach appears a safe and feasible intervention for people with de Quervain’s syndrome. A large multi-centre trial would be required to compare high- and low-load isometric exercises. Further research investigating exercise and multimodal interventions in this population is warranted.
The structure of informality: The Zambian copperbelt and the informal/formal dialectic
Authors: Finn Brandon Marc
Published: April 2023

The study of urban informality has exploded since Keith Hart theorized the term the ‘informal sector.' This explosion has coincided with a growing interest among urban scholars who train their eyes toward the ‘Global South.' Informality is used as shorthand for any number of urban experiences and realities ranging from the economy to governance, housing, the state, agency, political resistance, the urban form, and poverty. Much scholarship carefully illustrates different versions and modes of ‘informality,' while equating the term's first use with the provenance of the practice itself. Despite the global heterogeneity of informality, its instantiation can be traced further back than the 1960s and 1970s. Nearly half a century since the advent of the term the ‘informal sector,' we are still left with a deceptively simple question. If the creation and practice of informality predate African independence, where does it come from? This paper argues that the Zambian Copperbelt's early 20th–century history of urbanization and migration produced the informal/formal dialectic, establishing the grounds for inequalities that proliferate in the present. The structure of ‘informality’ finds its roots in colonial spatial strategies central to the formation of global capitalism. Through this dialectic, urbanization became a key mode of colonialism.
Sustainability Project Champions as Environmental Leaders in a City Organization: Driving the Urban Circular Economy
Authors: Pitkänen Jatta , Lehtimäki Hanna , Jokinen Ari
Published: April 2023

While the role of projects in sustainability change is widely recognized, the understanding of project managers’ behaviour in sustainability projects is limited. We examine project champions who act without hierarchical and authoritative power as environmental leaders and drive sustainability-related changes in the mindsets of actors and in city administration. Based on longitudinal action research, we elaborate on the practices and characteristics of project champions in initiating and advancing the circular economy in a city organization. Our study contributes to the intersection of research on project champions and environmental leaders by increasing the understanding of the ways through which champions develop their potency to promote sustainability in the course of the project.
Post COVID-19 Vaccination Side Effects and Associated Factors Among Vaccinated Clients in Bahir Dar City, Ethiopia
Authors: Siraj Ebrahim Abdela , Yayehrad Ashagrachew Tewabe , Yilma Zewdu , Getahun Tamyalew , Melaku Mequannent Sharew , Bizuneh Gizachew Kassahun , Kifle Zemene Demelash , Yimenu Dawit Kumilachew
Published: April 2023

Introduction

The lack of local side effect profiles for vaccines could hinder vaccination uptake. Since all COVID-19 vaccines are brand-new medications, it is crucial to keep track of any safety related concern.

Objective

This study is aimed to investigate post-vaccination side effects of COVID-19 vaccines and associated factors in Bahir Dar city.

Method

An institutional-based cross-sectional study was conducted among vaccinated clients. A simple random and a systematic random sampling method were used to select the health facilities and the participants, respectively. Bi-variable and multivariable binary logistic regression analyses were executed with odds ratio at 95% confidence intervals at p < .05.

Results

A total of 72(17.4%) participants reported at least one side effect following vaccination. The proportion prevalence was higher after the first dose than that of the second dose and the difference was also found to be statistically significant. In the multivariable logistic regression analysis female participants (AOR = 3.39, 95% CI =  1.53, 7.52), participants with a history of regular medication use (AOR = 3.34, 95% CI  =  1.52, 7.33), participants aged 55 and above (AOR = 2.93, 95% CI  =  1.23, 7.01), and participants who had taken only the first dose (AOR = 14.81, 95% CI  =  6.40, 34.31) were more likely to develop side effects for COVID 19 vaccination compared to their counterparts.

Conclusion

A significant number (17.4%) of participants reported at least one side effect following vaccination. Sex, medication, occupation, age, and type of vaccination dose were factors statistically associated with the reported side effects.
Genome-wide analysis of the metallothionein gene family in cassava reveals its role in response to physiological stress through the regulation of reactive oxygen species
Authors: Ma Yanyan , Xue Maofu , Zhang Xiaofei , Chen Songbi
Published: April 2023

Background

Cassava (Manihot esculenta Crantz) is widely planted in tropical and several subtropical regions in which drought, high temperatures, and other abiotic stresses occur. Metallothionein (MT) is a group of conjugated proteins with small molecular weight and rich in cysteine. These proteins play a substantial role in response to physiological stress through the regulation of reactive oxygen species (ROS). However, the biological functions of MT genes in cassava are unknown.

Results

A total of 10 MeMT genes were identified in the cassava genome. The MeMTs were divided into 3 groups (Types 2–4) based on the contents and distribution of Cys residues. The MeMTs exhibited tissue-specific expression and located on 7 chromosomes. The MeMT promoters contain some hormones regulatory and stresses responsiveness elements. MeMTs were upregulated under hydrogen peroxide (H2O2) treatment and in respond to post-harvest physiological deterioration (PPD). The results were consistent with defense-responsive cis-acting elements in the MeMT promoters. Further, four of MeMTs were selected and silenced by using the virus-induced gene silencing (VIGS) method to evaluate their functional characterization. The results of gene-silenced cassava suggest that MeMTs are involved in oxidative stress resistance, as ROS scavengers.

Conclusion

We identified the 10 MeMT genes, and explore their evolutionary relationship, conserved motif, and tissue-specific expression. The expression profiles of MeMTs under three kinds of abiotic stresses (wounding, low-temperature, and H2O2) and during PPD were analyzed. The tissue-specific expression and the response to abiotic stresses revealed the role of MT in plant growth and development. Furthermore, silenced expression of MeMTs in cassava leaves decreased its tolerance to ROS, consistent with its predicted role as ROS scavengers. In summary, our results suggest an important role of MeMTs in response to physiological stress as well as species adaptation via the regulation of ROS homeostasis.