bluuebunny/crossref_metadata_2025 huggingface dataset:
Possibilities of evaluation of trace element loading of river sediments on the example of the Svratka River and its tributaries
Authors: Kašperák Pavel , Kašperáková Dagmar , Geršlová Eva , Geršl Milan
Published: October 2023

Most methods of evaluating river system contamination use an enrichment factor, but there is no consensus concerning the specific values of the natural geochemical background to be. This is critical for evaluation of the anthropogenic loading. Taking into account that the final evaluation is strongly dependent on the choice of this parameter, the aim of the paper is to show the importance of the choice of the natural background in assessing the pollution degree of river sediments. Element concentrations of the surrounding rocks are considered to be the natural geochemical background. The Svratka River springs in the Žárské vrchy Highlands. It flows through crystalline rocks in upstream, and further then through metamorphic volcanic rocks, sediments of the Boskovice furrow and plutonic rocks of the Brno Massif. Further on, it flows through a straight watercourse over the plain of the Dyje-Svratka deep valley, and the downstream flows through Miocene sediments of the Carpathian foredeep and flysch units of the Western Carpathians (Fig. 1). 24 samples of river sediments were taken from the Svratka River and its tributaries (Fig. 1). The samples were decomposed in a solution of 1 ml HF (40%) and 3 ml HNO3 (65%). The Al, Ti and As contents were determined by AAS, the Pb, Zr contents were determined by FAAS, and Cr and Ni element contents were determined by ICP-MS (Table 2). The Enrichment Factor (EF) was calculated for each sample using Al, Ti and Zr as reference elements and recommended concentration of the natural background values in Table 1. The resulting EF values are very different (Fig. 2a, b). The results of the statistical processing for lead, arsenic, nickel and chromium (Fig. 3a–d) using the reference elements titanium, aluminium and zirconium demonstrated that the choice of the reference element is not the main factor that significantly influences the final evaluation. The choice of the appropriate natural geochemical background value is absolutely crucial for the evaluation of the anthropogenic loading
Asociación entre la exposición a violencia íntima de pareja contra la mujer y el reporte de secreción y úlceras genitales
Authors: Noriega Arce Nicole , Romaní-Romaní Franco
Published: October 2023

Introducción. La asociación entre la violencia contra la mujer y las infecciones de transmisión sexual es materia controversial. Objetivo. Evaluar la asociación entre la violencia íntima de pareja emocional, física y sexual con el auto reporte de secreción y úlcera genital en mujeres de participantes de una encuesta poblacional. Métodos. Se realizó un análisis de la Encuesta Demográfica y de Salud Familiar del Perú, 2021. Los criterios de inclusión fueron tener 15 a 49 años, ser casadas o convivientes, y estar seleccionadas y entrevistadas para el módulo de violencia doméstica. Se estimó la prevalencia de auto reporte de secreción y úlcera genital. La asociación con la violencia íntima de pareja fue realizada mediante regresión logística binaria con la estimación de la razón de probabilidades, considerando el diseño muestral complejo. Resultados. La prevalencia del reporte de úlcera o secreción genital fue 10,0%. La razón de probabilidades para reportar secreción o úlcera genital entre las mujeres que sufrieron violencia física leve comparado con las no expuestas fue 2,25 (IC95%: 1,72 a 2,94), el riesgo incrementó a 3,42 (IC95%; 2,39 a 4,90) entre las mujeres que sufrieron violencia física severa. La razón de probabilidades generada por la exposición a violencia sexual para reportar secreción o úlcera fue mayor (OR: 3,84, IC95%: 2,47 a 5,96). Conclusiones. Las mujeres expuestas a cada uno de los tres tipos de violencia íntima de pareja tienen mayor chance de reportar secreción o úlcera genital en los últimos 12 meses. El riesgo se incrementa cuando coexisten la forma física y sexual.
A propósito de una experiencia de gestión de la Sociedad Peruana de Obstetricia y Ginecología (SPOG)
Authors: Romero José Pacheco , Ciudad-Reynaud Manuel Antonio , Gutiérrez Ramos Miguel
Published: October 2023

Las sociedades médicas usualmente tienen como misión y visión la mejora de competencias de los asociados y por ello las actividades académicas suelen ser el punto más importante. La Sociedad Peruana de Obstetricia y Ginecología (SPOG) lo hace también, pero ha avanzado en el país hasta constituirse como referente de la salud de la mujer y es parte del grupo Asesor del Ministerio de Salud, promueve y defiende políticas públicas en beneficio de la salud sexual y reproductiva, como el impulso reciente de la vacunación de las gestantes contra el COVID-19 durante la pandemia que permitió reducir las muertes maternas. Y este año 2023, la SPOG defiende el derecho de las mujeres a la anticoncepción de emergencia ante el Tribunal Constitucional y del aborto terapéutico ante la Corte Suprema de Justicia. Además, se publica desde el año 1955 la Revista Peruana de Ginecología y Obstetricia (RPGO) que ha logrado recientemente su indexación a Scopus y siempre ha contado con el apoyo de las diferentes directivas de la SPOG. Revisando el último Plan Estratégico 2022-2026, consideramos que la SPOG es una Sociedad Académica Moderna que trata de ser autosostenible mediante la ejecución de proyectos con cooperación externa y de organismos internacionales y contando con el apoyo de los asociados y una administración moderna, una gestión con transparencia y eficiencia. En conclusión, las sociedades médicas del presente y del futuro no pueden conducir solo la actividad académica científica de la especialidad que desarrollan, sino también participar en las políticas públicas de salud del área de su competencia.
El enigma del coronavirus – La variante BA.2.86 – Lo nuevo sobre el COVID prolongado
Authors: Romero José Pacheco
Published: October 2023

El coronavirus ha continuado paseándose por el mundo con nuevas variantes,algunas consideradas de preocupación. Las hospitalizaciones aumentaron enalgunas partes con la variante BA.2.86, especialmente en personas mayores obesaso con morbilidad, pero han disminuido, así como los fallecimientos. Las mujeres quegestaron mediante técnicas de reproducción asistida tuvieron similar morbilidad quequienes gestaron espontáneamente, pero con más resultados maternoperinatalesadversos en aquellas de mayor edad, con embarazos múltiples, nuliparidad, índicede masa corporal >30. Los niños que nacieron al inicio de la pandemia mostraron unmicrobioma de diferente composición que quienes nacieron antes de la pandemia,lo que pudiera afectar su salud más adelante en la vida. Las personas que presentanCOVID prolongado, un cuarto de ellas sufre secuelas en órganos y sistemas, conlimitación y años perdidos de actividades, así como posibilidad de muerte prematura.El COVID prolongado ocurre más en mujeres entre 35 y 49 años y en quienestienen menos ingresos económicos. Podrían desarrollar diabetes tipo 2. Habríainteracciones directas entre el SARS-CoV-2 y proteínas mitocondriales esenciales enla producción de energía. El ARN viral ha sido detectado en lesiones ateroescleróticascoronarias y la espiga ha sido hallada en huesos del cráneo, meninges y cerebro.Las vacunas contra el coronavirus protegen a las gestantes y sus recién nacidosa través de transferencia placentaria y la lactancia. En la población, la inmunidadprotectora de la infección y de las vacunas declina con el tiempo y se requerirá nuevavacunación con una regularidad aún no determinada.
Medicina y Salud Centrada en la Mujer
Authors: Romero José Pacheco , Távara Orozco Luis
Published: October 2023

En el reciente exitoso Curso Medicina y Salud Centrada en la Personaen Latinoamérica hemos participado 57 docentes expertos provenientesde 16 países, la mayoría de América Latina, E.E. U.U., Canadáy países europeos. Asistieron varios cientos de profesionales de lasalud de América Latina, quienes recogieron un cúmulo importantede conocimientos y experiencias a ser trasladadas a nuestra realidad.
The Points to be Considered while Developing the Activities for the Mathematics Course
Authors: ÇENBERCİ Selin
Published: October 2023

The need for constructivist classroom environments in mathematics teaching cannot be ignored in order for sustainable development to continue. One of the most important applications of constructivist classroom environments in mathematics education all over the world is mathematical activities. The proficiency of pre-service mathematics teachers in developing activities will support constructivist classroom environments. In this study, it was aimed to reveal pre-service mathematics teachers' thoughts about what points they consider while they develop activities for mathematics courses. With this aim, an open-ended question was addressed to 23 pre-service teachers taking education at Elementary Mathematics Teaching program of a state university and having received the elective course of Activity Development in Mathematics Teaching. The obtained data was analyzed via the content analysis method. As a result of the study, it was determined that the participant elementary pre-service mathematics teachers expressed the points which they considered while developing activities with a total of 161 sentences or words. The statements obtained as a result of the analysis of the answers which the pre-service teachers gave to the research problem were gathered and examined under five sub-themes, namely general, purpose, scope, planning and the role of the teacher in practice. In respect of the points which elementary pre-service mathematics teachers considered while developing activities for mathematics courses, participants considered while developing activities for mathematics courses, they were observed to use statements which were mostly related to the sub-theme of the role of the teacher in practice. When it was evaluated in general, it has been observed that the participant elementary pre-service mathematics teachers are generally aware of the points to be emphasized. However, due to the low number of pre-service teachers who emphasized some points, it was concluded that they did not have enough knowledge about developing activities.
REFLEXIA RUSKÉHO FORMALIZMU V DIELE MIKULÁŠA BAKOŠA
Authors: Pašteková Soňa
Published: October 2023

Monografia skúma, do akej miery boli impulzy prekladov teoretických prác ruského formalizmu akceptované a produktívne pre vývin terminologického inštrumentária v slovenskom vedeckom prostredí. Zameriava sa na mapovanie a rekonštrukciu prekladateľských a literárnovedných aktivít M. Bakoša s akcentom na preklady vedeckých textov predstaviteľov ruskej formálnej školy, predovšetkým významných teoretikov prózy V. Šklovského a B. Ejchenbauma. Závery výskumu vnímame ako potenciálnu perspektívnu bázu pre širšie skúmanie Bakošovej vedeckej činnosti. Za základné metodologické východisko skúmania jeho prekladateľského a bádateľského prínosu pre oblasť modernej literárnej vedy považujeme interdisciplinárny, literárnohistorický a translatologický prístup.
THE INFLUENCE OF PHYSICAL THERAPY ON INDICATORS OF LOCOMOTIVE SYNDROME IN ELDERLY PERSONS WITH OSTEOARTHRITIS OF THE KNEE AND OBESITY
Authors: Aravitska Mariia H. , Saienko Olesia V.
Published: October 2023

Aim: to assess the effectiveness of the developed physical therapy program on locomotive syndrome parameters in elderly people with osteoarthritis of the knee and obesity.

Material and methods. 93 elderly people were examined. The control group consisted of 31 people without osteoarthritis of the joints, with no obesity. The main group 1 consisted of 33 people who received rehabilitation according to the general principles of osteoarthritis correction. Representatives of the main group 2 (31 people) were engaged in a physical therapy program using functional training on the «Prosedos» platform, therapeutic exercises, Proprioceptive Neuromuscular Facilitation; massage, kinesiological taping, nutritional correction, patient education. The effectiveness of the program was evaluated according to the dynamics of the Short Physical Performance Battery, Functional Gait Assessment, Tinetti-test (Performance-Oriented Mobility Assessment), 25-question Geriatric Locomotive Function Scale.

Results. Elderly patients with osteoarthritis of the knee and obesity were found to have impaired balance (Short Physical Performance Battery), altered gait stereotype (Functional Gait Assessment), risk of falling when performing activities of daily living (Tinetti-test) at the level of locomotive syndrome II degree (25- question Geriatric Locomotive Function Scale). The developed program of physical therapy in persons of the main group 2 revealed a statistically significantly better effect on the components of the locomotive syndrome compared to the initial examination in all studied parameters (p<0.05). Elderly patients who underwent rehabilitation according to the standard program for the correction of osteoarthritis achieved a statistically significant improvement compared to the initial state according to the studied parameters (p<0.05), but less pronounced compared to the tested program.

Conclusions. Elderly patients with osteoarthritis of the knee joints and obesity need to develop physical therapy programs taking into account and correcting the specifics of each condition, the presence of static and dynamic balance disorders and the risk of falling, which will increase the overall effectiveness of rehabilitation measures.
GUT MICROBIOTA AND CARDIOMETABOLIC RISK FACTORS IN CORONARY ARTERY DISEASE PATIENTS WITH ATRIAL FIBRILLATION
Authors: Melnychuk Iryna O.
Published: October 2023

The aim: To estimate gut microbiota composition peculiarities in patients with coronary artery disease (CAD) and atrial fibrillation (AF) and to evaluate their connections with known cardiometabolic risk factors (CRF).

Materials and methods: 300 patients formed 3 groups: I group – 149 CAD patients without rhythm disorders, II group – 124 patients with CAD and AF paroxysm and control group (CG) – 27 patients without CAD and arrhythmias. 16-S rRNA sequencing checked gut microbiota composition. CRF which was explored are total cholesterol (TC), triglycerides (TG), low density lipoproteins (LDL), high density lipoproteins (HDL), lipoprotein α (Lpα), apolipoprotein A1 (ApoA1), apolipoprotein B (ApoB), C-reactive protein (CRP), interleukin-6 (IL-6), trymetilamine (TMA) and trymetilamine-N-oxide (TMAO).

Results: The significant changes of gut microbiota composition were found in CAD patients with AF paroxysm in comparison with CAD patients without arrythmia as increasing Actinomycetota phulum (P<0.05); increasing Actinobacter Spp. and decreasing Blautia Spp., Roseburia Inulinivorans, Bacteroides Thetaiotaomicron (P<0.05). Moreover, Actinobacter Spp., Akkermansia Muciniphila, Streptococcus Spp., Bacteroides Thetaiotaomicron, Bifidobacterium Spp. have the highest amount of significant correlations with CRF (body mass index, LDL levels; P<0.05). By the ROC-analysis we found the acceptable role of Lactobacillus Spp., Bifidobacterium Spp., Bacteroides Thetaiotaomicron, Blautia Spp., Actinobacter Spp. and Eubacterium Rectale in AF paroxysm occurrence in CAD patients (area under ROC-curve (AUC)<0.7). We found gut microbiota combinations with highest AUC for AF paroxysm in CAD patient: all of them include Actinobacter Spp (Actinobacter Spp. + 0.32 * Streptococcus Spp., AUC = 0.9008; 1.56 * Actinobacter Spp. – Blautia Spp., AUC = 0.9008;1.84 * Actinobacter Spp. – Akkermansia Muciniphila, AUC = 0.9008). AF paroxysm duration in CAD patients depends of plasma IL-6, TMAO, fecal Actinobacter Spp. and Akkermansia Muciniphila by the linear multifactorial regression analysis (AF paroxysm duration = 0.68*(Actinobacter Spp., lg/CFU/ml) – 3.33*(Akkermansia Muciniphila, lg/CFU/ml) – 0.6*IL6 – 0.34*TMAO – 0.98).

Conclusions: Gut microbiota condition is closely connected with occurrence AF of paroxysm in CAD patients. To find out the new ways of gut microbiota and CRF correction will be interesting in future investigations.
IMPOSTORS AMONG FAMILY DOCTORS
Authors: Vysochyna Iryna L. , Kramarchuk Volodymyr V. , Yashkina Tetiana O.
Published: October 2023

Introduction. Human resources policy issues in medicine have always played a significant role in ensuring quality medical care for the population. Young specialists face high labor market demands and constant management pressure, without having ready adaptation strategies. The beginning of a success story is always challenging, and sometimes the impostor syndrome can have its influence. Persistent self-doubt leads to emotional exhaustion and the development of a cynical attitude towards others, which can further transform into burnout syndrome.

THE AIM: To analyze the prevalence of the impostor phenomenon among young doctors in the field of “General Practice – Family Medicine” and explore potential correlations with burnout syndrome.

MATERIALS AND METHODS. We conducted an anonymous cross-sectional survey of 27 young family doctors using The Clance Impostor Phenomenon Scale and Maslach Burnout Inventory Human Services Survey for Medical Personnel. The research procedure adhered to accepted moral norms, rights, interests, and personal dignity of the participants, in line with the principles of bioethics outlined in the Helsinki Declaration “Ethical Principles for Medical Research Involving Human Subjects” and the “Universal Declaration on Bioethics and Human Rights (UNESCO)”.

RESULTS. All respondents demonstrated a certain level of impostor syndrome severity, which might be related to a shift in professional role – the transition from intern to independent practitioner – a family doctor. Every fourth intern already showed signs of emotional exhaustion and depersonalization, with 7% having developed burnout syndrome. It is not excluded that these changes are linked to working conditions and military actions on the territory of Ukraine.

CONCLUSIONS. Nearly half of the respondents were categorized under intermediate burnout syndrome profiles (Overloaded, Ineffective, Detached), which can be corrected with timely identification and effective management. Without exception, all respondents exhibited various degrees of the impostor phenomenon. The impostor syndrome is closely related to emotional exhaustion (p=0.002) and depersonalization (p=0.000214) within the structure of burnout syndrome, allowing for the development of new correction approaches and optimization of burnout prevention strategies.
Penurunan Kadar TSS Dan BOD Pada Pengolahan Limbah Cair Tahu Dengan Metode Elektrokoagulasi
Authors: Subuharni Nujulia , Masthura  , Ety Jumiati
Published: October 2023

Dalam metode elektrokoagulasi, yang menggunakan elektroda yang bertindak sebagai koagulan untuk melepaskan ion-ion logam yang ada di dalam air dan menghilangkan kotoran, arus listrik dialirkan melalui air. Limbah cair tahu harus diolah sebelum dibuang ke air karena sering kali dibuang ke badan air yang mungkin memiliki pengaruh negatif terhadap kualitas air. Penelitian ini bertujuan untuk menurunkan kadar TSS dan BOD pada limbah cair tahu dengan metode elektrokoagulasi. Air limbah yang digunakan dalam penelitian ini dikumpulkan dari Jl Abri Dusun III Desa Pancur Batu Hulu Kecamatan Pancur Batu, Kabupaten Deli Serdang, Sumatera Utara. Parameter yang dievaluasi adalah TSS dan BOD yang mengacu pada Peraturan Menteri Lingkungan Hidup dan Kehutanan Republik Indonesia Nomor P.68/Menlhk-Setjen Tahun 2016, dengan variasi waktu 40, 45, dan 50 menit pada tegangan 12 volt dan jarak elektroda 2 cm. Hasil analisa menunjukkan persentase penurunan kadar TSS dan BOD tertinggi saat waktu 50 menit. Hal ini akan menurunkan kadar TSS sebesar 90,05% dan BOD sebesar 70,89% maka ini menunjukkan bahwa metode elektrokoagulasi efektif digunakan untuk mengolah limbah cair tahu.
Efektivitas Penurunan Kadar Fe Dan Mn Pada Air Sumur Gali Kelurahan Jati Utomo Kota Binjai Dengan Metode Filtrasi
Authors: Qorina Rizki , Masthura Masthura , Jumiati Ety
Published: October 2023

Penelitian ini telah dilakukan untuk mengetahui penurunan kadar Fe dan Mn pada air sumur gali menggunakan bahan karbon aktif kulit pisang kepok aktivator HCl 5 M dan zeolit yang bertujuan untuk mendapatkan kualitas air bersih berdasarkan PERMENKES RI. No 2 Tahun 2023. Variasi komposisi karbon aktif kulit pisang kepok dan zeolit pada sampel A (25%:75%), sampel B (50%:50%) dan sampel C (75%:25%). Media pemfilteran menggunakan housing filter berukuran 10 inchi dengan tinggi 19,5 cm. Hasil penelitian menujukkan hahwa desain pemfilteran yang optimal yaitu pada sampel C dengan penurunan nilai kadar Fe sebesar 97,88% dan nilai kadar Mn sebesar 98,25% yang sesuai dengan standar mutu air bersih menurut PERMENKES RI No. 2 Tahun 2023.
Konsumsi Energi Pirolisator Kondensor Ganda Untuk Konversi Serbuk Kayu Jati Dan Meranti Menjadi Asap Cair
Authors: Febriana Ida , Effendy Sahrul , Zurohaina  , Krysthin Venny , Fenoldi Nova
Published: October 2023

Biomassa merupakan salah satu dari sekian banyak jenis sampah yang ramah lingkungan karena dapat didaur ulang menjadi barang yang bermanfaat jika dikelola dengan baik. Terdapat suatu metode yang cukup efektif untuk mengolah biomassa menjadi bernilai ekonomis yaitu dengan menggunakan metode pirolisis guna menghasilkan asap cair. Dilakukannya penelitian ini bertujuan untuk mengetahui jumlah konsumsi energi, total rendemen dan kualitas asap cair yang dihasilkan sesuai standar ASTM D7544. Proses pirolisis yang dilakukan ini memiliki variabel tetap berupa variabel bahan baku yaitu limbah serbuk kayu jati dan limbah serbuk kayu meranti dengan ukuran sampel yaitu 20-60 mesh sedangkan untuk variabel kendali, percobaan dilakukan dengan suhu 325⁰C. Dari hasil penelitian yang dilakukan, nilai konsumsi energi terendah diperoleh dari serbuk kayu meranti 60 mesh sebesar 9,08 kWh/l pada konsumsi daya 5,28 kWh dan total produk 0,581 liter, rendemen tertinggi sebesar 16% dari serbuk kayu jati 60 mesh, dan semua kondensat 1 asap cair dari masing-masing bahan baku sudah memenuhi standar fisik dari ASTM D7544 (densitas 1,1-1,3 gr/ml dan pH 2-3), serta standar kimia dari jurnal Maulina (2018) yaitu kadar asam 2,8-9,5% dan kadar fenol 0,2-2,9%.
Participation of MiR-145-5p in Neuronal Ischemia/Reperfusion Injury by Targeting Fibroblast Growth Factor-5
Authors: Xu Lei
Published: October 2023

The researchers made efforts in elucidating the mechanism for miR-145-5p participating in neuronal ischemia/reperfusion injury (I/R) via targeting fibroblast growth factor-5 (FGF5). OGD/R was performed to construct the neuronal injury model. After OGD/R, the oxidative stress injury of nerve cells was enhanced significantly, the levels of lactic dehydrogenase, reactive oxygen species and malondialdehyde rose, while the superoxide dismutase activity decreased. Both miR-145-5p and cell apoptosis rate increased. MiR-145-5p had a targeting relation to FGF5. After miR- 145-5p inhibitor transfection of nerve cells, inhibition of oxidative stress together with apoptosis was observed. FGF5 siRNA could reverse the impact on oxidative stress, FGF5, and apoptosis exerted by miR-145-5p-inhibitor in the OGD/ R model. Being a latent target of I/R treatment, miR-145-5p induces the oxidative stress injury as well as apoptosis of HT22 cells by targeting and binding FGF5.
Health Condition of Traffic Police Personnel in Nagpur Division of Maharashtra, India
Authors: Sahu Prafull Kumar
Published: October 2023

Overweight and obesity is a medical condition in which abnormal or excess body fat has accumulated to an extreme that may harm health and reduce life expectancy. It may increase the risk of hypertension, diabetes mellitus, cardiovascular disease and musculoskeletal disorder.The investigation has been conducted to assess overweight and obesity and understand its relation with the morbidity pattern in traffic police personnel.The present investigation has been conducted in the Nagpur division among 277 traffic police personnel, including both male and female police personnel. Information has been collected through an interview schedule.The study shows that more than 50 percent of traffic police personnel are overweight, and 17 percent are obese. Between male and female traffic police personnel, there is a significant difference in BMI (ᵪ2 =14.069, df=3, p=0.003). Forty percent of traffic police personnel suffer from musculoskeletal disorders, cardiovascular disease, and diabetes in 11 percent of traffic police personnel.
Pertanggungjawaban Pidana Rumah Sakit atas Kelalaian Perawat yang Mengakibatkan Tertukarnya Bayi yang Baru Dilahirkan dalam Perspektif Hukum Kesehatan di Indonesia
Authors: Yandriza Yandriza , Arma Diana
Published: October 2023

The process of enforcing criminal law should be carried out for the nurse's negligence which resulted in the exchange of newborn babies, bearing in mind that criminal law aims to protect against crimes against body and life, especially since the main victim is a baby/child where everything must be done in the best interests of the child. child. The law does not always discuss several compensations, but must also discuss the "Right to Life, and the Right to Defend Life.
The Development of the Cavitated Volume Fraction as a Creep Damage Indicator for Creep Remnant Life Prediction
Authors: Okpa Mbombo Amejima , Xu Qiang , Lu Zhongyu
Published: October 2023

This paper highlights the advantages of using the cavitated volume fraction (fv) as a superior creep damage indicator compared to traditional two dimensional (2D) based parameters. With the emergence of three dimensional (3D) experimental techniques like X-ray tomography, in-situ volumetric observations have become feasible, enabling a more accurate assessment of creep damage. The cavitated volume fraction offers a comprehensive evaluation of cavity distribution, overcoming the limitations of missing information and the impact of cavity coalescence on 2D-based assessments. We present the procedure for deriving the cavitated volume fraction using the cavity size distribution function and the cavity growth pattern equation. Additionally, we discuss the potential application of the cavitated volume fraction for rupture time prediction using early-stage creep data. Overall, this paper emphasizes the importance of adopting 3D-based parameters, specifically the cavitated volume fraction, for improved creep damage assessment and lifetime prediction.
Estimation of Composites Delamination due to the Edge Effect
Authors: Evtushenko M.A. , Skvortsov Yu.V. , Khnyryova E.S.
Published: October 2023

The paper investigates the possibility of delamination near the free edges of composites is investigated by the example of a two-dimensional formulation of the Pipes-Pagano problem. A bilinear material damage law based on the cohesive zone model (CZM) is considered. An example of selecting the stiffness of a cohesive layer is given, and a calculation of a laminated composite by the finite element method in the ANSYS program is performed. The method used makes it possible to determine the concentration of interlaminar stresses due to the edge effect, and, using a special set of interface elements simulating mating surfaces and following process of delaminaton, to investigate the composite delamination. When interface elements are added, the problem becomes non-linear and the solution in a two-dimensional formulation significantly reduces labor intensity and simplifies modeling, and also allows you to specify a large number of elements over the thickness of each layer. The problems with the convergence of the solution that have arisen can be eliminated with the help of special numerical modeling techniques and by varying the parameters embedded in the program. The revealed damage to the cohesive layer due to the edge effect can lead to delamination and premature failure of composites. The presented results can be used in the design of products from composite materials in rocket and space technology.
Mechanical Characterization of AA6061/Clay (Kaolinite) Composites for Industrial Application
Authors: Udoye N.E. , Asikoko F.C. , Fayomi O.S.I. , Okeniyi J.O.
Published: October 2023

Traditional materials have certain restrictions in an industrial application today inhibiting them from the attainment of the best blend of toughness, density and strength. The paradigm shift in the use of agro-waste products as particulate reinforcement is an excellent choice owing to the inexpensive and availability of the desired agro-waste product. This research focuses on the development of AA6061 aluminium alloy through stir casting method using kaolinite clay as the reinforcement agent in increasing weight percentages of 2.5wt %, 5wt %, 7.5wt % and 10wt %.. The use of agro-waste as reinforcements is possible as the clay kaolinite was effectively infused into the pure matrix for composites to be constructed. The tensile strength was highest at the addition of 10 wt % of clay kaolinite. Brinell’s hardness test showed an increase in value with an increase in the mass fraction of clay. It was observed from the results of the tests carried out that the reinforced specimens exhibited improved hardness when analyzed using Brinell’s hardness machine. Some of these properties improved with the increase in weight percentage of reinforcement particles. This research has shown the importance of agricultural waste to material engineers, material handlers and metallurgists in our society and that it is the right way to go.
Facile Synthesis and Supercapacitive Properties of PDA/UiO-66 Composites
Authors: Cao Chunhua , Wang Yazhen
Published: October 2023

UiO-66 in Zr-MOFs materials stands out in the research of supercapacitors due to its large specific surface, high stability and high heat resistance. In this paper, pure UiO-66 was successfully prepared using solvothermal method, and three PDA/UiO-66 composites with addition mass ratio of UiO-66 and dopamine of 2:1, 3:1 and 4:1 were prepared by autopolymerizing dopamine hydrochloride to form polydopamine at room temperature. The materials’ morphology and structure were examined using SEM, TEM and XRD, and the capacitive performances were analyzed by CV and GCD. The results indicated that the capacitor properties of UiO-66 could be improved to a certain extent with the appropriate amount of polydopamine coating. The PDA/UiO-66 composite with a mass ratio of 2:1 displayed a high specific capacitance of 822.04 F/g at 1 A/g, and maintained good capacity retention even after 4000 charge/discharge cycles in a three-electrode system. These results suggested that the PDA/UiO-66 composite had great potential as a supercapacitor electrode material.
Study on Deformed and Solution Treatment Microstructure Evolution of 2219 Alloy
Authors: Wang Yan , Cao Hailong , Tian Yuxing , Song Xiaoyu , Tong Meimei , Yang Senlin
Published: October 2023

The thermal deformation behavior of 2219 alloy is studied by using the Gleeble-1500 thermal simulation testing machine under different deformation conditions, the deformation temperature is 350°C∼500°C and the strain rate is 0.01∼1s-1. The results show that when the strain rate increases, the flow stress also increases. However, when the deformation temperature increases, the flow stress decreases. Analyzing the deformed and solution treatment microstructure evolution of 2219 alloy though the electron back-scattering diffraction (EBSD). There are mainly deformed grains and only a few recrystallization grains of 2219 alloy after thermal deformed. When the deformation temperature is high and the strain rate is low, it is easy to occur dynamic recrystallization. After solution treatment, the microstructure of 2219 alloy occurs static recrystallization, which is advantageous at 350°C and 0.1s-1. When the deformation temperature is low and the strain rate is large, it is easy to occur static recrystallization after solution treatment. When 2219 alloy deforms at higher temperatures, using a higher strain rate can effectively suppress recrystallization.
Analysis of the Thermal Deformation Behaviour of Ti2AlNb-Based Alloys Based on a Modified and Optimised Zerilli-Armstrong Model
Authors: Liu Jie , Wang Kelu , Li Xin , Zhou Tong , Wang Zengqiang
Published: October 2023

Isothermal constant strain rate compression of Ti2AlNb-based alloys was carried out using a Gleeble-3500 thermal simulation tester with deformation temperatures of 650-850°C, strain rate interval of 0.001–1s-1, on the basis of which a modified Zerilli-Armstrong model and an optimised Zerilli-Armstrong model were developed to describe the thermal deformation behaviour of Ti2AlNb-based alloys. The results show that the error between the predicted and experimental values of the modified Zerilli-Armstrong model is larger, with correlation coefficients R and EAR of 0.935 and 12.4% respectively, while the optimised Zerilli-Armstrong model can predict the flow stress better, with correlation coefficients R and EAR of 0.964 and 10.5% respectively. The optimised Zerilli-Armstrong model had high prediction accuracy and wider applicability, making it more suitable as a constitutive model for predicting the thermal deformation behaviour of Ti2AlNb-based alloys.
Study on Performance and Size of 3D Printing of Polycarbonate Materials
Authors: Liang Wen , You Xiaoping , Liang Yuxian , Dong Qiyuan , Chen Xin
Published: October 2023

The method of melting the 3D printed parts of polycarbonate materials in the high temperature resistant mold by high temperature heating, holding them for a period of time, and then placing them in the air for Free cooling to reshape the internal parts. For the corner brackets, post-processing was conducted, followed by testing for tensile strength, roughness, installation precision analysis, and installation surface analysis. The results showed that, when the melting temperature was 280 with a retention time of 25 minutes, the tensile strength of the corner brackets increased by 227.71% compared to the original brackets, and the roughness decreased by 61.72%. The positioning dimension error values of the brackets were all less than 1%, and the inner hole dimension error values were all less than 3.5%. Although there was a granular or uneven surface phenomenon in the installation surface of the three different placement positions, they still met the assembly requirements.
Morphological and Tensile Strength of Low-Density Polyethylene/Polyethylene Terephthalate Blends
Authors: Lanh Nguyen Thanh , Thuan Trinh Nam , Nga Pham Thi Hong
Published: October 2023

Low – Density Polyethylene (LDPE) is a thermoplastic made from ethylene monomer, with slightly soft properties, high strength and good impact resistance. This study aimed to improve the mechanical properties of LDPE by mixing it with Polyethylene Terephthalate (PET). This study tested the mixing of LDPE with PET in the respective ratios of 100/0, 95/5, 90/10, 85/15 and 80/20, and then used injection molding to create the mixture. The samples were measured for tensile strength according to ASTM D638. Tensile strength measurements using PET concentrations of 0%, 5%, 10%, 15%, and 20%, respectively, demonstrate that the tensile strength is 12.89, 12.65, 10.97, 12.07, and 13.4 MPa. In addition, in this experiment we used an optical microscope to study microstructure, the results showed spherical PET particles interwoven into the LDPE substrate, but no interphase adhesion was observed. According to the results, LDPE/PET composites will have a variety of uses in the future. Overall, the tensile strength of LDPE/PET composites allows for different applications
Dynamic Analysis of Skid Landing Gear of UAV Under Ground Contact Condition BASED on Finite Element Method
Authors: Yang Haoyuan , Wang Yue , Dong Jie , Wang Hong
Published: October 2023

In this paper, 3D modeling software is used to conduct structural modeling of skid landing gear of parachute landing recovery UAV, and then LS/DYNA analysis module of ANSYS software is used to conduct dynamic simulation analysis of the landing gear, which is used to simulate the structural working condition of the landing gear when the UAV lands at different attitudes and speeds and impacts the soil and concrete ground. Based on the changes of the momentum, deformation and stress of the landing gear during the simulation period, it is necessary to ground the UAV with a steady attitude Angle on the soil soft landing surface. At the same time, through the analysis of the maximum equivalent stress and safety factor of the landing gear structure at the moment of impact, the connection of the landing gear components is most vulnerable to impact damage, and it is necessary to strengthen the structure and carry out margin control on the structure, which provides theoretical guidance for the structural improvement of UAV recovery device in the future.
Structural Parameter Optimization and Fatigue Life Analysis of POM Flexspline in Harmonic Drive
Authors: Hu Qiushi , Wang Chao , Xue Shangwu , Li Heng , Li Lei
Published: October 2023

The flexspline, as a core component of the harmonic drive, is highly susceptible to fatigue failure due to elastic deformation and alternating stress during operation. Its performance directly affects the working life of the harmonic drive. In this paper, finite element modeling and analysis were carried out on the polyoxymethylene flexspline (POM FS), resulting in stress, displacement, and strain cloud maps. Then, using the control variable method, the influence of structural parameters such as cylinder length L, wall thickness d, and chamfer radius r on the maximum stress of POM FS was studied, and the structural parameters were optimized. Finally, the fatigue life of POM FS was analyzed based on the S-N curve of POM. The results show that the optimized POM FS has a fatigue life of 18,300 hours, which is 24% higher than the original POM FS with the initial parameters. This paper provides a technical reference for the optimization and improvement of the lifespan of POM FS.
Research About the Poisson’s Ratio of a Deployable Structure Based on the Kresling Origami
Authors: Wang Haotian , Wang Hongjin , Han Yafeng
Published: October 2023

Due to its unique mechanical properties, broad application prospect and design freedom, Kresling structure has been proven as a valuable tool to build deployable structures in numerous fields such as medical devices, high-tech weaponry and aerospace. However, the stress concentration caused by deformation incompatibility will occur when the structure is applied in combination with other structures Therefore, the deformation characteristic of the structure is studied in this paper. Different from the classical configuration, the Kresling structure whose relative angle (φ) between the top and bottom panels is 0 is selected in this paper. After simplification, the Poisson’s ratio of the structure during deploying and collapsing is studied, and the corresponding numerical model is constructed. Finally, finite element simulation is carried out to verify the numerical model, and the error between the simulation result and the numerical model is 2.81%, which demonstrates that the numerical model possesses the capacity to describe Poisson’s ratio of Kresling structure. In addition, the model proposed in this paper can also be utilized to predict the Poisson’s ratio of the model whose φ is not 0, which will have a significant effect in broadening the application range of the Kresling structure.
Research on the Pollution Status and Cleaning Methods of Automotive Air Conditioning Pipelines
Authors: Fei Qiang , Chen Mingxi , Wu Junlin , Jiang Hanyou , Jin Biao , Zhang Heli
Published: October 2023

The automotive air conditioning system has three basic functions, namely the need to achieve refrigeration, heating, and ventilation functions. When the external circulation of the car air conditioner is turned on, fresh air from the outside is sucked in from the car. After being heated or cooled by the car air conditioning system, it enters the car through the air outlet of the air conditioner to achieve external circulation of air. During this process, the air brought into the car from the air conditioning outlet will not only mix with a large amount of dust in the outside air, but also contain pollutants such as car exhaust and pollen. Due to the relatively closed environment inside the car, such air entering the car will not only pollute the air inside the car, but also affect people’s physical health if left in this environment for a long time. Experiments were conducted to demonstrate the severity of accumulated dust and microbial pollution in the air conditioning pipeline system of automobiles, determine the universality of the pollution situation, and analyze the current status of cleaning methods at home and abroad. It is necessary to study the composition and principles of automotive air conditioning systems and air conditioning pipeline structures, laying the foundation for designing new air conditioning pipeline cleaning devices.
Lightweight Beam Structure Topology Design Solution for Steel and Aluminum Hybrid Body
Authors: Xing Chen , Liu Bo
Published: October 2023

To solve the problems of low bending and torsional stiffness and high weight of the all-steel body-in-white (BIW), an aluminum (Al) alloy profile with optimized cross-section is used to replace the original sheet metal threshold beam. Firstly, considering the feasibility of extrusion process, the Al alloy profile cross-section is designed based on the original threshold beam cross-section. Then, we extracted the equivalent load acting on the center of mass of the threshold beam section during the calculation of the bending and torsional stiffness of the BIW, and carried out the planar topology optimization with the design boundary conditions to minimize the cross-sectional flexibility, resulting in an Al alloy section with superior performance. The optimization results show that the bending stiffness and torsional stiffness of the BIW are improved by 2.1% and 3.4%, respectively, after replacing the Al alloy foundation beam with internal reinforcing ribs. Additionally, there is a 5.0% enhancement in first-order bending mode and a 2.7% improvement in first-order torsional mode, accompanied by a slight weight reduction of 0.1%.
Numerical Study on the Effect of Geometric Parameters on the Heat Transfer Performance of Finned-Tube Adsorption Bed
Authors: Liu Jia , Zou Tonghua , Li Hongxuan , Hui Qingling
Published: October 2023

Due to the benefits in terms of conserving energy and emission reduction, which are coincident with the current energy development trend, adsorption refrigeration technology has gained popularity. The central part of the adsorption refrigeration system is the adsorption bed, in which heat transfer performance has a direct impact on the system’s efficiency. A numerical model of a finned-tube heat exchanger in a silica-gel water adsorption refrigeration system has been built as a numerical model for this study. A mathematical model along with Darcy’s law has been considered to take into the effects of heat and transfer. On how well heat transfer occurs, the influences of geometric factors including fin height, fin thickness, fin pitch, and porosity of silica gel were obtained. The findings indicate the heat exchanger’s heat transmission is uniform, with a maximum temperature differential of 1.14 K on its fin. The heat exchanger reaches a stable average temperature at the fastest rate with a 10 mm fin height. The optimal fin pitch of the adsorption bed is 2.2 mm. The heat exchanger performs better with a fin that is 0.22 mm thick. Overall, the study supplies an analytical and methodological basis for the influence of geometric factors on heat transmission in adsorption beds and generates new structural optimization ideas.
Estimation of Maximum Temperature Deformations of Solar Panels of Earth Remote Sensing Small Satellite “Aist-2D”
Authors: Serdakova V.V.
Published: October 2023

This article evaluates the temperature deformations of a solar battery panel of a small satellite “Aist-2D” designed for the Earth remote sensing as a result of a thermal shock. Such an assessment is necessary for successful performance of the target tasks of remote sensing of the Earth by a small spacecraft. As a result of the temperature shock, the orientation requirements of the spacecraft may be violated. This is especially true for the angular velocity requirements. The maximum deflection of solar panel is estimated using a one-dimensional thermoelasticity model. The incident heat flux is assumed to be perpendicular to the surface of the solar panel. The panel itself has a flat, non-deformed shape at the time of the temperature shock. This situation makes it possible to estimate the maximum effect of the thermal shock. In this case, the solar panel heating will be maximal. Significance of perturbations from temperature shock leads to the need to take it into account in the analysis of orbital motion of the spacecraft. The stress-strain state of the solar panel has been investigated. The dependences of the deflection of the solar panel points during the temperature shock are obtained. The results of the estimation can be used to assess the impact of thermal shock on the task execution of “Aist-2D”.
Experimental Research Regarding the Flow Pattern and Pressure Drop in a Slurry Composed of Polypropylene-Particles
Authors: Fan Jinchao , Xu Zhaohui , Fang Chao , Lin Zili
Published: October 2023

Pipelines used for product transportation require regular cleaning. A new method has emerged using slurry for the cleaning process, during which the flow pattern and pressure drop in the slurry are essential. The flow of slurry containing polypropylene particles was investigated using a laboratory-scale, closed-circuit pipeline facility. While the slurry was pumped, the pressure drop was measured, and the flow pattern was observed regarding particle type, slurry particle concentration, and slurry flow velocity. The results showed that after the critical flow velocity, the particles mixed uniformly with the water in the pipe, increasing the pressure drop in conjunction with the flow velocity. Although a higher particle mass fraction and small particle size reduced the critical flow velocity, the mass fraction and particle size had no significant influence on the pressure drop. This research establishes a solid foundation for the practical application of this cleaning method.
Study of Tensile Strength of Solder Joints of Through-Hole Cartridge Components Based on Full Factorial Design of Experiments
Authors: Zhang Ling , Fan Xun , Deng Chao , Liu Xiaobin , Gao Chao
Published: October 2023

This study conducts an experimental study of the tensile strength of cartridge solder joints for the effect of welding process parameters on the tensile properties of cartridge components. To design 16 sets of different combinations of assembly process parameters based on full analysis factor experiments, to complete the cartridge assembly components solder joint tension test experiments and obtain the corresponding solder joint tensile strength data; The main and interaction effects of the welded joint tensile strength data were analyzed to clarify the degree of influence of each process parameter on the tensile strength of welded joints. The results show that the main effect analysis, with a main effect value of 10.81 for the solder dispensing time, has the most significant effect on the tensile strength of the cartridge component solder joints; In the interaction analysis, the interaction effect value of solder dispensing time with spot diameter is 3.14, which has a significant effect on the tensile strength of the cartridge solder joints. At the same time, the increase of solder dispensing time and spot diameter increases the tensile strength of the solder joint, showing a positive correlation. Therefore, setting long solder dispensing time and large spot diameter can improve the tensile strength of cartridge solder joints.