bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterizing the behavior of blended concrete incorporating metakaolin and quarry dust: an experimental investigation
Authors: Parmar Nilesh R. , Salla Sanjay R. , Khungar Hariom P. , Kondraivendhan B.
Published: February 2024

Purpose

This study aims to characterize the behavior of blended concrete, including metakaolin (MK) and quarry dust (QD), as supplementary cementing materials. The study focuses on evaluating the effects of these materials on the fresh and hardened properties of concrete.

Design/methodology/approach

MK, a pozzolanic material, and QD, a fine aggregate by-product, are potentially sustainable alternatives for enhancing concrete performance and reducing environmental impact. The addition of different percentages of MK enhances the pozzolanic reaction, resulting in improved strength development. Furthermore, the optimum dosage of MK, mixed with QD, and mechanical properties like compressive, flexural and split tensile strength of concrete were evaluated to investigate the synergetic effect of MK and quarry dust for M20-grade concrete.

Findings

The results reveal the influence of metakaolin and QD on the overall performance of blended concrete. Cost analysis showed that the optimum mix can reduce the 7%–8% overall cost of the materials for M20-grade concrete. Energy analysis showed that the optimum mix can reduce 7%–8% energy consumption.

Originality/value

The effective utilization is determined with the help of the analytical hierarchy process method to find an optimal solution among the selected criteria. According to the AHP analysis, the optimum content of MK and quarry dust is 12% and 16%, respectively, performing best among all other trial mixes.
Death by remote control: Drone warfare in Afghanistan, Ukraine and beyond
Authors: González Roberto J.
Published: February 2024

This article examines the use of military drones over the past 20 years. It includes the following: (1) a critical review of how drone warfare in the US‐led ‘war on terror’ affected drone crews and those ‘living under drones’; (2) an analysis of how drone warfare in Ukraine and Russia differs from previous deployments of the technology; and (3) a careful assessment of what lies ahead, as national governments and technology firms race to develop AI‐enabled drones and autonomous weapons systems on a broad scale.
Guns, gangs and metal: The double‐edged sword of protection inside Beirut's scrap economies
Authors: Saleh Elizabeth
Published: February 2024

In Beirut, the role of ‘local strong men’, known as the masoul, has significantly transformed, particularly in Lebanon's financial crisis and since the devastating Beirut port explosion in August 2020. Traditionally, these armed henchmen, affiliated with mainstream political parties, have exerted control over the scrap metal industry, from collection to transportation. However, the increasing profitability of scrap metal, notably copper and iron – long‐standing leading exports – has led to new forms of ‘local strong men’, termed ‘asabet (gangs). These groups have escalated violence, breaking from what was previously considered normative behaviour. This article examines these evolving protection practices and their implications for Lebanon's sociopolitical landscape.
Survival of pre‐formed zirconia crowns in primary teeth: a prospective practice‐based cohort study
Authors: Foster M , Patel J , Turlach B , Anthonappa R
Published: February 2024

Background

This study aimed to investigate the (1) survival probabilities of prefabricated zirconia crowns (PZCs) placed on primary teeth and (2) identify demographic and tooth‐related factors that might affect survival probability.

Methods

This study prospectively followed children treated under general anaesthesia by a single practitioner between 2012 and 2020. Demographic variables including the age at treatment, gender and tooth‐related variables including FDI tooth number, crown size used and any procedural complications at postoperative reviews were collected.

Results

A total of 155 children involving 319 teeth with PZCs were followed up between 12 and 78 months postoperatively with a mean of 38 months. Of the 319 crowns followed, five failures were observed in three patients requiring extraction. Other procedural complications noted included fracture (n = 3), overhangs (n = 3), internal resorption (n = 5) and 24% of crowns showed signs of radiographic changes on postoperative radiographs when these were taken. Age at treatment, tooth type and need for pulp therapy were not statistically associated with clinical success (P > 0.1).

Conclusions

PZCs provide an aesthetic and durable solution in the management of children with early childhood caries. This study shows very good clinical success and survival extending up to 78 months for PZCs placed on primary teeth under general anaesthesia.
The systematic structural studies of some Byzantine ceramic fragments from Dobrudja region of Romania: Raman spectroscopy, neutron diffraction, and imaging data
Authors: Zhomartova Ayazhan Zh. , Abdurakhimov Bekhzodjon A. , Talmațchi Cristina , Kichanov Sergey E. , Kozlenko Denis P. , Bǎlǎșoiu Maria , Talmațchi Gabriel , Șova Constantin , Belc Marius C.
Published: February 2024

The systematic studies of composition and spatial distribution of main phases inside volume of 25 fragments of Byzantine ceramic obtained in archeological works in the Dobrudja region, Romania, have been performed using neutron diffraction and tomography, and Raman spectroscopy. The obtained structural data on the content of phases, the presence of calcite grains and pores, and the uniformity of phase spatial distribution made it possible to systematize the studied fragments and correlate them with clay sources or pottery workshop. The experimental possibilities of neutron methods of nondestructive structural diagnostics as well as the structural markers provided by them in the studies of ceramic samples are discussed.
Constructing victimhood in Canadian news coverage of HIV criminalisation: Claims‐making activities and HIV non‐disclosure
Authors: Aguinaldo Jeffrey P. , Greenspan Nicole R.
Published: February 2024

A robust body of research has documented the representational politics of news coverage in their depiction of HIV‐positive people charged for HIV non‐disclosure. News media representations of HIV‐negative sex partners in cases of HIV non‐disclosure have received far less scholarly attention. Adopting a social constructionist perspective, this article identifies how “victims” of HIV non‐disclosure are constructed in news media. It is based on a dataset consisting of 341 news articles on HIV non‐disclosure from 14 English Canadian newspapers across the political spectrum. Victims of HIV non‐disclosure were constructed as: (1) suffering horribly, (2) morally pure and virtuous, (3) vengeful and (4) agentic and responsible for their situation. We consider how such constructions are enmeshed within arguments that establish or reject HIV non‐disclosure as a social problem. We then discuss the ways these constructions and the assumptions upon which they are based reflect broader discussions on the severity of HIV, the responsibility for HIV risk and exposure, and the contestations over the very nature of the social problem of HIV non‐disclosure. Constructions of victims that uphold HIV criminalisation have relied on assumptions of HIV as a deadly disease but de‐emphasise personal responsibility for HIV risk. By contrast, constructions of victims that, in effect, oppose HIV criminalisation have tended to minimise the harms of HIV and invoke personal responsibility for HIV risk. We suggest that both proponents and opponents of HIV criminalisation engage in the “ideology of victimhood” and thus participate in and reinforce what Best (1997) termed, the “victim industry.”
Know thy audience: Children teach basic or complex facts depending on the learner's maturity
Authors: Qiu Fanxiao Wani , Ipek Canan , Gottesman Elizabeth , Moll Henrike
Published: February 2024

What kind of information is appropriate to teach depends on learner characteristics. In three experiments, 5‐ to 7‐year‐old children (N = 170, 50% female, 68% White; data collection: 2022–2023) chose between basic and complex information to teach an infant or adult audience. The older, but not younger, children, taught more complex information to adults and more basic information to infants, (OR = 2.03). Both ages overcame their own preference for complex information when teaching infants (h = .45). Children's reflections on why they made particular pedagogical choices did not predict audience‐contingent teaching. The findings suggest that young children can infer what kind of information is suitable given a learner's maturity, with a key developmental progression between ages 5 and 7.
Analysing governance‐led infrastructural development nexus in sub‐Saharan Africa: Does the moderating role of institutional quality matter?
Authors: Appiah Michael , Onifade Stephen Taiwo , Gyamfi Bright Akwasi
Published: February 2024

Governments engage in infrastructural developments across the globe, and the level of success often colligates with institutional quality levels. However, despite the presence of governance, the lack of well‐developed infrastructure has bedevilled sub‐Saharan African (SSA) countries for decades. Therefore, this study investigates the governance‐led infrastructural development hypothesis for the SSA region from an institutional quality perspective towards addressing the infrastructural deficit challenges of the region. A combination of advanced panel econometric techniques was applied to data collected from the African Development Bank, World Bank World Development Indicator, and International Monetary Fund (IMF) to investigate the governance‐led infrastructural development hypothesis in SSA while controlling for financial development, economic growth, and industrialization in the region. The findings show that the interaction of institutional quality measures and governance indicators significantly and positively induces infrastructure in sub‐Saharan Africa (SSA). Additionally, while economic growth and financial development yield no expected significant influence on infrastructural developments, industrialization plays a crucial role, as its spillover effects are not confined to boosting economic growth alone but also to infrastructural transformations. Thus, the provision of policy frameworks by authorities to strengthen institutions and promote good governance is vital for articulating and facilitating infrastructural development plans for SSA.
Safety and effectiveness of SARS‐CoV‐2 vaccines for patients with intractable hepatobiliary diseases: A multicenter, questionnaire‐based, cross‐sectional study
Authors: Tanifuji Ayaka , Ohfuji Satoko , Matsumoto Kosuke , Abe Masanori , Komori Atsumasa , Takahashi Atsushi , Kawata Kazuhito , Sato Ken , Joshita Satoru , Umemura Takeji , Ueno Masayuki , Nakayama Nobuaki , Kakisaka Keisuke , Arinaga‐Hino Teruko , Ito Koichi , Kanai Sachiko , Miura Ryo , Arizumi Toshihiko , Asaoka Yoshinari , Ito Takanori , Shimizu Tetsuya , Yoshida Hiroshi , Ohta Masayuki , Mizuno Suguru , Isayama Hiroyuki , Morimoto Youichi , Mochida Satoshi , Ohira Hiromasa , Tanaka Atsushi
Published: February 2024

Aim

There are few data regarding the safety and effectiveness of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) vaccines in patients with intractable hepatobiliary diseases. We conducted a multicenter, questionnaire‐based, cross‐sectional study to determine the safety and effectiveness of the SARS‐CoV‐2 vaccines in Japanese patients with intractable hepatobiliary disease.

Methods

Patients aged ≥18 years with autoimmune hepatitis (AIH), primary biliary cholangitis, primary sclerosing cholangitis, Budd–Chiari syndrome, idiopathic portal hypertension, and extrahepatic portal vein obstruction at each center were consecutively invited to join the study. Participants were asked to complete a questionnaire regarding their characteristics, vaccination status, post‐vaccination adverse effects, and SARS‐CoV‐2 infection. Additionally, liver disease status, treatment regimens, and liver function test values pre‐ and post‐vaccination were collected.

Results

The survey was conducted from September 2021 to May 2022, and 528 patients (220 AIH, 251 primary biliary cholangitis, 6 AIH– primary biliary cholangitis/primary sclerosing cholangitis overlap, 39 primary sclerosing cholangitis, 4 Budd–Chiari syndrome, 5 idiopathic portal hypertension, and 3 extrahepatic portal vein obstruction) participated in the study. Post‐vaccination adverse effects were comparable to those observed in the general population. Post‐vaccination liver injuries classified as grade 1 or higher were observed in 83 cases (16%), whereas grades 2 and 3 were observed in only six cases (1.1%); AIH‐like liver injury requiring treatment was not observed. Overall, 12 patients (2.3%) were infected with SARS‐CoV‐2, and only one patient was infected 6 months after the second vaccination.

Conclusion

SARS‐CoV‐2 vaccines demonstrated satisfactory safety and effectiveness in Japanese patients with intractable hepatobiliary diseases.
Hemostatic imbalance induced by tamoxifen in estrogen receptor‐positive breast cancer patients: An observational study
Authors: Didembourg Marie , Reda Sara , Oldenburg Johannes , Rühl Heiko , Douxfils Jonathan , Morimont Laure
Published: February 2024

Background

Estrogen receptor (ER)‐positive (ER+) breast cancer accounts for approximately 75% of all breast cancers. Tamoxifen, a selective estrogen receptor modulator, is the standard adjuvant treatment. Although better tolerated than aromatase inhibitors, tamoxifen increases the risk of venous thromboembolism (VTE) 1.4‐fold.

Aim

To assess the hemostatic imbalance induced by tamoxifen in adjuvant treatment of ER+ breast cancer.

Method

Twenty‐five patients in remission from ER+ breast cancer under tamoxifen were included. One hundred and thirty one age‐ and BMI‐matched healthy controls were included to establish reference ranges of thrombin generation assay (TGA) parameters. TGA was performed in the absence and presence of exogenous activated protein C (APC) to calculate the normalized APC sensitivity ratio (nAPCsr), a marker of APC resistance.

Results

All TG parameters except the endogenous thrombin potential (ETP) (−APC) were significantly impacted by tamoxifen (p < 0.001). In absence of APC, regardless of TGA parameters, at least 50% of results were outside the reference ranges except for ETP, which was above the upper reference limit in only two individuals. The most impacted parameter was the Peak Height with 52% (−APC) and 80% (+APC) of results above the upper reference range limit, respectively. The nAPCsr was significantly higher in tamoxifen users (mean ± standard deviation = 3.18 ± 0.91) compared to the control group (2.19 ± 0.92, p < 0.0001).

Conclusion

This observational study showed that patients in remission from ER+ breast cancer taking tamoxifen had altered thrombin generation, as well as an acquired APC resistance. Moreover, this is the first study using the validated ETP‐based APC resistance assay in tamoxifen‐treated patients.
The changing profile of infective endocarditis: A multi‐year retrospective study for dentists
Authors: Kumar Ashok , Casamassimo Paul , Kovalchin John , Claman Daniel , Peng Jin , McDaniel Jodee , Hunt W. Garrett , Wong Chloe A.
Published: February 2024

Background

Infective endocarditis (IE) has high morbidity and mortality and is often attributed to dental procedures.

Aim

This study characterized variables related to paediatric IE in a paediatric hospital cohort.

Design

A retrospective review of medical records, from January 1, 2008, to January 1, 2020, to examine demographic, medical and dental history, and risk factors associated with children diagnosed with IE at Nationwide Children's Hospital.

Results

Of the 242 patients who were admitted with tentative IE diagnoses, 67 met the inclusion criteria: 46 (69%) had underlying cardiac conditions and 21 (31%) had not. One‐third had an infection with S. aureus and viridans streptococci. Age was significantly associated with intracardiac devices in children with IE. Mean hospitalization was 25 days, and the mortality was 6 (9%); 41(61%) required surgery for causative defects, and 24 (32%) had dental consultation during admission.

Conclusion

Although cardiac‐related conditions were present in most cases, IE occurred in patients without cardiac factors.
A relationship analysis of the effects of COVID‐19 isolation on pressure sores in a tertiary hospital
Authors: Kim Min Ji , Lee Jun Suk , Mok Jung Ho , Lim Hyoseob , Hahn Hyung Min , Lee Il Jae
Published: February 2024

Management of pressure sores can have various environmental effects; moreover, the COVID‐19 pandemic notably affected efforts towards effective management of pressure sores. Some cases of COVID‐19 infections require long‐term hospitalization in the intensive care unit. Moreover, special protective equipment worn by physicians owing to the pandemic complicate wound management. In this study, we compared the pressure ulcer characteristics between isolated patients with and those without COVID‐19 and evaluated the effects of isolation on pressure sores. From November 2022 to February 2023, patients who had pressure sores were included and their medical records were reviewed retrospectively. The experimental group included patients with confirmed COVID‐19 infections, who received clinical treatment in an isolated unit. Wound characteristics in each group and associated risk factors were analysed. Fifty‐four isolated patients with COVID‐19 and 58 control patients were included. The Braden Scale score and Korea patient classification system‐1 did not vary significantly between the two groups. However, the number of Grade I pressure sores in the COVID‐19 isolation group was significantly lower than those in the control group (p < 0.001), while the number of lesions was significantly higher (p = 0.034). The mortality rate in the COVID‐19 isolation group was higher than that in the control group (p = 0.008), and more patients were discharged with unhealed wounds (p = 0.004). A higher treatment effect on pressure sores may be expected if the disease is more actively managed. Moreover, the wound care systems for isolated patients with COVID‐19 require further attention.
Epistemologies and Aesthetics of Curriculum, Pedagogical Praxis and Assessment in the Visual Arts: A Comparative Analysis of the International Baccalaureate Diploma Programme and the New South Wales Stage 6 Visual Arts Syllabus
Authors: Blaikie Fiona , Maras Karen
Published: February 2024

We compare epistemologies and aesthetics in the International Baccalaureate Diploma Programme and the Australian New South Wales Stage 6 Visual Arts Syllabus, focusing on curriculum content, pedagogical praxis, and assessment strategies. Both curricula feature making, reflexivity, and critique. International Baccalaureate components are Exhibition, the Process Portfolio, and the Comparative Study. In New South Wales Visual Arts they are the Body of Work and Visual Diary. Issues are the teacher as curriculum; uneven resources; shifting contexts and formulating standardized expectations. In both, qualitative assessment and examination are achieved via articulating criteria and levels of achievement, and examiner training. In International Baccalaureate, what counts as good work can vary in relation to Principal Examiner standards, particularities of context, pedagogy, and resources, with work ranging from sophisticated installations, to anime, to the school art style. In New South Wales Visual Art aesthetic conventions are reinforced because the system is less distributed than International Baccalaureate, where aesthetics become engrained, perpetuating conventions around what counts as good art. In spite of supervening assessment structures, teaching, learning, and assessment in visual arts education is always highly qualitative, unfolding, and rooted in the situated shifting conditions and ways of being in the world of each teacher, student, artwork, examiner, artist, and scholar.
Neuroendocrine carcinoma of the uterine cervix with extensive pagetoid spread pattern
Authors: Sakurai Azusa , Yamanoi Koji , Yamaguchi Ken , Hamanishi Junzo , Minamiguchi Sachiko , Mandai Masaki
Published: February 2024

There have been no reported cases of neuroendocrine carcinoma (NEC) of the cervix with pagetoid spread (Pag‐S). A 44‐year‐old woman came to our department because of abnormal cytology that persisted immediately after a radical hysterectomy for NEC of the cervix. A mapping biopsy in a large area from the vaginal wall to the vulva revealed that synaptophysin/Ki‐67‐positive tumor cells were scattered within the epithelium in multiple areas, suggesting a wide Pag‐S of NEC. Because tumor cells were found beyond the vaginal wall, the anterior pelvic exenteration was performed. Since we could pathologically confirm the complete resection and no distant metastases were detected, no adjuvant therapy was performed. Four years have passed since the initial treatment without any tumor recurrence. It is known that the prognosis of NEC of the cervix that invades beyond the cervix is poor; however, if there is a Pag‐S pattern, a radical surgical treatment can be considered.
Boreal ecopoetics: Christian Dotremont's site‐specific writing in Sápmi
Authors: Sjöberg Sami
Published: February 2024

Northern Fennoscandia entered Christian Dotremont's (1922–1979) imagination in 1956. The Belgian avant‐gardist was comfortable in Central‐European artistic milieus through his involvement in CoBrA (1948–1951), but a total of 12 journeys to Sápmi between 1956 and 1978 had a profound effect on his creative work, especially the logograms he is best known for. This article studies Dotremont's travel writings and logograms as site‐specific forms of writing, which can be seen as precursors to ecopoetic approaches. Dotremont's journeys took place at a cultural turning point, when ethnographers had made their field trips but mass tourism was still in its embryonic state in Sápmi. His Sápmi‐inspired travel writings reveal how the idealism related to a hyperborean north initially intrigued him while he sought to elude modernity. Dotremont's cultural exchanges in Sápmi were non‐artistic but manifested in his art and writing. Sápmi brought about an ecological awakening through awe that was not sublimated but a lived experience. Dotremont immersed himself in Sápmi, with fundamental repercussions to his creative exploits.
Elevated evolutionary rates of biting biomechanics reveal patterns of extraordinary craniodental adaptations in some herbivorous dinosaurs
Authors: Kunz Callum , Sakamoto Manabu
Published: February 2024

Adaptation to specialist ecological niches is a key innovation that has contributed to the evolutionary success of many vertebrate clades, underpinning the acquisition of diverse skull morphologies. Dinosaurs, which dominated Mesozoic terrestrial faunas, acquired herbivory multiple times, and evolution of these herbivorous adaptations is linked to drastic changes in dental and craniomandibular functional morphology, yet whether changes in functionally relevant phenotypic traits occurred more rapidly in herbivorous lineages compared to in carnivorous lineages remains largely untested in a statistical phylogenetic framework. Here, we infer rates of phenotypic evolution using phylogenetic variable‐rate models on relative biting edge (tooth row) lengths of 107 dinosaur taxa to test the hypothesis that the acquisition of herbivory is associated with rapid changes in mandibular biomechanics. We find elevated rates of biomechanical evolution in theropods with foreshortened and beaked skulls (Oviraptorosauria, Limusaurus), as well as in ceratopsians and Diplodocus. The presence and position of a reduced tooth row and increased jaw efficiency unite these high‐rate lineages, indicating selection for greater efficiency in biting biomechanics. Large departures from the isometric scaling of these mandibular characteristics helps explain the differences in evolutionary rates in these clades and those of other herbivorous theropods (Therizinosauria, Ornithomimosauria). Additionally, we hypothesize that extreme ontogenetic changes within species lifetimes may be behind some instances of branch‐wise elevated rates. Thus, we show how exceptional rates of biomechanical evolution can reveal signatures of ecological adaptations within dinosaur lineages as well as within‐species ontogenetic sequences.
Modulation of excited state intramolecular proton transfer and intramolecular charge transfer pathways of symmetrical azines through micellar medium
Authors: Suhasini Ramalingam , Venkatasubramanian Ulagammal , Thiagarajan Viruthachalam
Published: February 2024

The photophysical studies of fluorescent probes in micellar medium can give a better insight about their interaction with biological membranes. This study attempts to access the photophysical properties of the dual emitting azine based probe diethylamino salicylidene azine dimer (DEASAD) in micellar media. DEASAD showed dual charge transfer emission due to the presence of open enol (480 nm) and closed enol (510 nm) forms in polar protic solvents. Upon increasing the concentration of ionic surfactants, there is a significant increase in the emission intensity of both the enol forms of DEASAD until premicellar concentration. After micellization, occurrence of a new anomalous keto form emission through excited state intramolecular proton transfer (ESIPT) was observed around 530 nm in ionic micelles and its intensity changes depend on the micellar surface charge. The emission studies revealed the position and interaction of DEASAD with the charge of micellar stern layer as confirmed through interaction of metal ion with the probe and control molecules with and without ESIPT and ICT moieties. In contrast, the new anomalous longer wavelength keto form of DEASAD emission was absent in neutral micelles like Triton X‐100.
Beaver dam analogs did not improve beaver translocation outcomes in a desert river
Authors: Sandbach Christine , Young Julie K. , Conner Mary , Hansen Emma , Budy Phaedra
Published: February 2024

Stream restoration programs employ beaver‐related restoration techniques, including beaver translocations and installation of beaver dam analogs (BDA), to create complex in‐stream habitat. We investigated whether BDA installations improved the probability of translocated beavers surviving and colonizing a section of a degraded desert river. We translocated beavers fitted with tracking devices to the Price River, Utah, United States, for 2 years before and after BDAs were installed. We monitored survival and site fidelity of beavers to estimate apparent survival (φ), using model selection to evaluate models with BDA, flow, and other factors hypothesized to relate to apparent survival. We found similar apparent survival 8 weeks post‐release of pre‐BDA (φ = 0.50 ± 0.08 SE) and post‐BDA beavers (φ = 0.41 ± 0.06 SE). There were 15 predator‐caused mortalities and 39 beavers emigrated out of the study site. Top models indicated apparent survival was negatively related to mean flow. Of the 70 BDAs constructed, beaver activity was detected on only two structures and the number of intact natural dams decreased due to monsoon floods. Our results suggest BDAs may not improve survival and site fidelity of translocated beavers in desert river systems. Instead, the dynamic flow of desert rivers and negative relationship between flow and apparent survival suggest the timing of release may be an important consideration for successful beaver translocation. Additional research is needed to understand how habitat, food availability, individual behavior, and resident conspecifics influence beaver translocation success.
Workers organizing in the platform economy: Local forms and global trends of collective action
Authors: Rafélis de Broves Olivier , Kang Minhyoung , Grohmann Rafael , Barcellos Victor , Gomes Mano Felipe , Yoon Cheolki , Jamil Rabih
Published: February 2024

Distinctive features of the on‐demand work platforms made it theoretically improbable for workers to organize and for collective forms of protest to emerge. Their business model and work arrangements spatially isolate and socially individualize workers, subjectivizing them as competing micro‐enterprises rather than co‐workers. However, faced with the flood of the platforms on a global scale, collective actions of platform workers surged like a backwash, especially in the ride‐hailing and food delivery sectors, during the last decade. Observers witnessed a great variety in the combination of actors involved and repertoire of actions mobilized worldwide. Despite this diversity, some common global trends can be sketched out. Through a literature review focused on Europe, Latin America, North America and Asia, this article shows that workers struggle globally to build a collective actor, through an original combination of new and old forms of protest. They ought to compensate for their weak marketplace bargaining power by leveraging their discursive, associational, coalitional and workplace bargaining powers.
Imaging diagnosis: CT characteristics of a retrobulbar hibernoma in a dog
Authors: Craig Cameron J , Young Benjamin D , Andries Courtney V , Aschenbroich Sophie A
Published: February 2024

A 12‐year‐old female spayed Beagle was referred for investigation of exophthalmos. CT revealed a well‐defined, retrobulbar mass causing rostro‐dorsal displacement of the left globe. The mass had a mildly heterogeneous precontrast soft tissue attenuation with mild heterogeneous enhancement following iohexol administration. The mass was surgically removed en bloc with an orbital exenteration. Histopathology confirmed the mass to be a hibernoma, a benign tumor of brown adipose tissue. Hibernomas have CT characteristics consistent with both benign and malignant adipose tumors and may be underrecognized by radiologists.
Genetic influences on motor learning and performance and superperforming mutants revealed by random mutational survey of the mouse genome
Authors: Jakkamsetti Vikram , Ma Qian , Angulo Gustavo , Scudder William , Beutler Bruce , Pascual Juan M.
Published: February 2024

Evolution depends upon genetic variations that influence physiology. As defined in a genetic screen, phenotypic performance may be enhanced or degraded by such mutations. We set out to detect mutations that influence motor function, including motor learning. Thus, we tested the motor effects of 36,444 non‐synonymous coding/splicing mutations induced in the germline of C57BL/6J mice with N‐ethyl–N‐nitrosourea by measuring changes in the performance of repetitive rotarod trials while blinded to genotype. Automated meiotic mapping was used to implicate individual mutations in causation. In total, 32,726 mice bearing all the variant alleles were screened. This was complemented with the simultaneous testing of 1408 normal mice for reference. In total, 16.3% of autosomal genes were thus rendered detectably hypomorphic or nullified by mutations in homozygosity and motor tested in at least three mice. This approach allowed us to identify superperformance mutations in Rif1, Tk1, Fan1 and Mn1. These genes are primarily related, among other less well‐characterized functions, to nucleic acid biology. We also associated distinct motor learning patterns with groups of functionally related genes. These functional sets included, preferentially, histone H3 methyltransferase activity for mice that learnt at an accelerated rate relative to the remaining mutant mice. The results allow for an estimation of the fraction of mutations that can modify a behaviour influential for evolution such as locomotion. They may also enable, once the loci are further validated and the mechanisms elucidated, the harnessing of the activity of the newly identified genes to enhance motor ability or to counterbalance disability or disease.

image

Key points

We studied the effect of chemically induced random mutations on mouse motor performance.

An array of mutations influenced the rate of motor learning.

DNA regulation genes predominated among these mutant loci.

Several mutations in unsuspected genes led to superperformance.

Assuming little‐biased mutagenicity, the results allow for an estimation of the probability for any spontaneous mutation to influence a behaviour such as motor learning and ultimate performance.
Analysis and Modeling of Turbulence Anisotropy of a Swirled Hot Streak Flow
Authors: Wingel Christopher , Binder Nicolas , Bousquet Yannick , Boussuge Jean-François , Buffaz Nicolas , Le Guyader Sébastien
Published: February 2024

This study is carried out in the context of hot streak flows in high-pressure turbines, for which a correct prediction of the temperature evolution is required. The present work particularly focuses on the turbulence anisotropy analysis of a swirled hot streak flow in a bent channel representative of a nozzle guide vane (NGV) passage of a high-pressure turbine. Large-eddy simulations are conducted with the in-house solver IC3 in order to measure and characterize the anisotropy of turbulence. Moreover, to evaluate turbulence modeling, steady simulations of the bent channel are performed with the elsA software, which solves the Reynolds-averaged Navier–Stokes (RANS) equations. LES is first used to complete a turbulent kinetic energy (TKE) budget that enables to understand the energetic transfers associated with turbulence. This budget reveals two distinct zones where turbulence activity is impacted when the curvature is reached. The analysis of the anisotropy of turbulence based on two metrics highlights a misalignment of the Reynolds stress tensor and the mean strain-rate tensor (Schmitt's criterion), and a strong anisotropy developing inside the bent duct (Lumley's analysis) that may cause the failure of the classical RANS turbulence models based on Boussinesq's hypothesis. To check this hypothesis, RANS is positioned against LES with different turbulence models that accounts or not for the anisotropy of turbulence. Both turbulence activity (TKE budgets, Lumley's analysis) and aerothermal fields (radial distributions) are compared. Results show that Explicit Algebraic Reynolds Turbulence Models (EARSM) enable to better account for the anisotropy of turbulence, which in turn promote a better prediction of temperature, both in terms of intensity and trajectory.
Development and Verification of a Higher-Order Computational Fluid Dynamics Solver
Authors: Tyson William C. , Jackson Charles W. , Roy Christopher J.
Published: February 2024

Over the past two decades, higher-order methods have gained much broader use in computational science and engineering as these schemes are often more efficient per degree-of-freedom at achieving a prescribed error tolerance than lower-order methods. During this time, higher-order variants of most discretization schemes, such as finite difference methods, finite volume methods, and finite element methods, have emerged. The finite volume method is arguably the most widely used discretization technique in production-level computational fluid dynamics solvers due to its robustness and conservation properties. However, most finite volume solvers only employ a conventional second-order scheme. To leverage the benefits of higher-order methods, the higher-order finite volume method seems the most natural for those seeking to extend their legacy solvers to higher-order. Nonetheless, ensuring higher-order accuracy is maintained is quite challenging as the implementation requirements for a higher-order scheme are much greater than those of a lower-order scheme. In this work, a methodology for verifying higher-order finite volume codes is presented. The higher-order finite volume method is outlined in detail. Order verification tests are proposed for all major components, including the treatment of curved boundaries and the higher-order solution reconstruction. System-level verification tests are performed using the weak form of the method of manufactured solutions. Several canonical verification cases are also presented for the Euler and laminar Navier–Stokes equations.
Searching for Suitable Binary Fluid for an Ejector Heat Pump for Domestic Water Heating
Authors: Wang Pengtao , Abu-Heiba Ahmad , Mohammed Ramy H. , Spitzenberger Jeremy , Kowalski Stephen , Ismael Laith , Ma Hongbin , Nawaz Kashif
Published: February 2024

Water heating is a major source of energy consumption in the U.S. residential sector. Heat pumps can significantly increase the energy efficiency of water heating. An ejector heat pump (EHP) is a novel, thermally driven heat pump that uses an ejector as a thermocompressor. Choosing suitable working fluids is critical in developing high-performance EHPs. Therefore, this research screens binary fluid pairs (BFPs) for EHPs to produce domestic hot water at a high coefficient of performance (COP). The criteria for screening BFP candidates for EHP water heaters (EHPWHs) are established, and BFP candidates are shortlisted. This study identifies HFE7000, Novec649, HFE7100, HFE7200, and HFE7500 for the primary fluids and RE170, R600a, R600, and R1234ze(Z) for the secondary fluids. The thermodynamic model is employed to investigate the performance of EHPWHs using the shortlisted BFPs under various operating parameters, including the evaporation pressure of the primary working fluid in the high-temperature evaporator and the condensation temperature. The highest heating-cycle COP of 1.328 is achieved by an EHPWH operating with HFE7000/R600 at a condenser temperature of 50 °C and a pressure of 1.69 MPa in the high-temperature evaporator.
Limits on Kinetic Impact Deflection of Asteroids from Laboratory Hypervelocity Cratering and Disruption of Meteorites and Analogs
Authors: Flynn George J. , Durda Daniel D. , Strait Melissa M. , Macke Robert J.
Published: February 2024

Successful deflection of a hazardous asteroid by kinetic impact requires cratering without disruption in order to avoid possibly leaving a large fragment of the asteroid on a collision course with Earth. A critical issue is the determination of the maximum change in velocity, and thus the orbital change, that can be imparted to asteroid material by a single hypervelocity kinetic impact while producing only cratering rather than fragmentation. Porosity, strength, mineralogy, and hydration influence the response of a target to hypervelocity impact. To investigate the maximum velocity that can be transferred by a single kinetic impact we performed a series of laboratory-scale hypervelocity impact cratering and disruption measurements on two types of anhydrous asteroid samples, the Northwest Africa (NWA) 869 ordinary chondrite meteorite and the NWA 4502 carbonaceous chondrite meteorite, using the NASA Ames Vertical Gun Range. Our results demonstrate that if disruption is to be avoided there is a factor of seven difference in the maximum velocity that can be imparted by a single kinetic impact between these two types of asteroid material. To investigate the effect of hydration on the maximum velocity transfer we impacted laboratory-prepared simulant of a hydrous carbonaceous meteorite target and determined that its behavior was similar to that of the NWA 4502 targets. Our results indicate that the maximum velocity change that can be imparted by a single kinetic impactor to this carbonaceous meteorite target is only ~0.27 m/s. This suggests that multiple kinetic impacts may be required for non-disruptive deflection of many Potentially Hazardous Asteroids, particularly the weaker carbonaceous asteroids.
Wave Structuring Viscosity in the Shock Compaction of Solid Matter
Authors: Grady Dennis
Published: February 2024

When subjected to projectile impact, or the load imparted by detonation of an energetic explosive, the effected regions of a solid material will undergo pressure-induced compression through the passage of a shock wave initiated by the impact or explosion. Extent of compression is dictated by both the nature of the material and the intensity of the impact or explosion. The time history of compression as the shock wave encompasses a region within the granular material is rapid. Transient local temperature and density extremes can occur. The time history of the energy imparted by the shock wave is central to assessment of physical and chemical transitions brought about by the event. This time history is dictated by a solid-state viscosity of the shock-wave effected material.
In-Situ Observation of Stress-Field Propagation and Damage Formation in Hypervelocity-Impacted Glass Materials
Authors: Kawai Nobuaki , Uemura Tomo , Watanabe Kazuma , Hasegawa Sunao
Published: February 2024

Hypervelocity impact experiments have been conducted on quartz glass and soda-lime glass to observe directly the impactinduced damage process progressing inside materials. Stress wave propagation and damage evolution associated with hypervelocity impact are visualized by employing the Edge-on Impact technique coupled with the polarized light shadowgraphy or scattered-light imaging method using an ultra-high-speed video camera. Recorded images clearly show how stress waves propagate and interact with each other, and how damages form and propagate during hypervelocity-impact events. A comparison of damage structures between quartz and soda-lime glasses reveals that differences in the short-range order of atomic configurations can affect the formation of macroscopic impact damage in amorphous materials such as glass. In experiments with a target consisting of two soda-lime glass components stacked in the direction of the ballistic axis, it is observed that damage form and propagate in the vicinity of the interface due to the interaction between the contact interface of the two glass components and the stress wave.
Numerical Modeling of High-Speed Impacts Involving thin Film
Authors: Kupchella Ryan , Ruoff Chaz
Published: February 2024

A parallelized approach for simulating tearing in thin material with a hydro-structural code is presented. The approach is built upon the shell finite element formulation and incorporates a simple remeshing scheme to facilitate material separation behind propagating tears. Tear propagation is handled using an implementation of the Virtual Crack Closure Technique (VCCT) to predict fracture based on the homogenized critical strain energy release rate (Gc). The approach is demonstrated with a simulation of an impact event from a joint JAXA/NASA series of light gas gun tests. A marked improvement in model outcome with the use of the VCCT implementation is demonstrated through quantitative and qualitative comparisons between numerical debris characteristics and experimental data.
Mesoscale Modeling of High-Velocity Impact on Thick-Section Woven Composites
Authors: Meyer Christopher S. , Gillespie John W. , Haque Bazle Z. (Gama)
Published: February 2024

This work presents an approach for modeling high-velocity impact on multi-layered plain weave composites. This approach resolves plain weave architecture with mesoscale detail, and applies the continuum assumption to the microscale. Models include rate-dependent material constitutive, damage and failure behavior, and rate-dependent cohesive interfacial failure. Rate-dependent cohesive traction-separation laws were derived from previously published microscale models of fracture. The modeling approach was validated by comparing the predicted impact versus residual velocity (VI-VR) response to previously published experimental results. Finally, the model is used to predict the VI-VR response for a 22-layer composite and the results are compared with experimental results from the literature. Good correlation is shown between experiment and model predictions.
2D VS 3D: Does Perspective Affect Thermography Temperature Values
Authors: Cagle Colton , Croessmann Charles L. , Ritchie Cole , Muniz Frank , Pantoya Michelle
Published: February 2024

Thermography is a common diagnostic for measuring spatially resolved surface temperatures. Extreme environments such as high-velocity impact testing employ thermography to probe fireball dynamics for modeling and simulation efforts. However, emissivity and related optical density are major roadblocks for accuracy. In this study, a variety of reactive projectiles are launched at 1300m/s and observed with single camera thermography from two 90° perspectives. The effect of flame shape on optical density and subsequently emissivity is compared between the different viewing angles. Trends indicate that asymmetric flames create varying optical densities between perspectives, resulting in up to 7% difference in reported median temperatures for the same flame. A maximum of 11% total difference is reported, with 6% due entirely to optical density effects. It is concluded that different viewing angles provide valuable insight into optical density and emissivity functions, and uncertainties of reported temperatures should account for this potential inaccuracy.
Railgun Launch of Cylindrical and Conical Projectiles at Muzzle Velocities up to 2100 M/S
Authors: Reck B. , Alouahabi F. , Hassler Q. , Schneider M.
Published: February 2024

Electromagnetic railguns are able to launch projectiles at velocities beyond 2500 m/s. The French-German Research Institute of Saint-Louis ISL has been operating railguns of various sizes for more than 25 years, ranging from small caliber (10-mm) guns to the 6-m long NGL60 launcher with a 60 mm square caliber. In this work, the launch and sabot discard process of projectiles is investigated, using ISL’s 3-m long railgun of caliber 25 mm. Two different types of projectiles are examined. The first type has a cylindrical geometry with a conical nose. By choosing different lengths, the projectile mass ranges from 15 to 60 grams. A thread allows for the transfer of the acceleration load from the armature-sabot petals to the cylinder. The muzzle velocities of this test series are located between 1300 m/s and 2100 m/s. The second type is a coneshaped projectile, made of copper alloy, with a base diameter of 20 mm and a round nose. Velocities up to about 1600 m/s were achieved with this type. Relevant insight in the mechanisms limiting the muzzle velocity could be obtained, which proves beneficial for future launcher up-scaling. The particular feature of the launch package design for both types of projectiles is the common separation of armature and sabot. Symmetrical discard makes sure that their craters of impact do not interfere with the projectile impact in the center region of the target plate.
Simulating Hypervelocity Impacts on Cfrp with a Discrete Element Approach
Authors: Watson Erkai , Durr Nathanaël , Murillo Jose-Luis Sandoval , Büttner Markus , Matura Pascal
Published: February 2024

Numerical simulations provide a powerful tool for investigating satellite breakups resulting from hypervelocity impact, and a discrete element simulation method has been shown to be well suited to model the fragmentation that materials undergo upon impact at high velocities. In this paper, we describe new developments to a discrete element simulation method to allow the modeling of orthotropic materials, specifically carbon fiber reinforced polymers which are commonly used in modern satellites. We model carbon fiber reinforced polymers by using different parameters for fiber and matrix materials in our discrete model. We calibrate our carbon fiber reinforced polymer model’s two free parameters with experimental hypervelocity impact data from literature. Finally, we demonstrate the numerical method’s applicability to simulate the satellite breakups with two simulations: a non-catastrophic sphere-CubeSat impact and a catastrophic CubeSat-CubeSat impact. We compare these scenarios, using aluminum and carbon fiber reinforced polymer CubeSats, to fragment size distributions predicted by the NASA standard satellite breakup model.