bluuebunny/crossref_metadata_2025 huggingface dataset:
Cosméticos com presença de disruptores endócrinos e gestação: percepção de risco pelos profissionais de saúde
Authors: Souza Laís dos Santos Rocha , Oliveira Neta Ana Izabel de , Gomes Júlia Souza , Andrade e Silva Érika , Emidio Suellen Cristina Dias , Paraiso Alanna Fernandes
Published: October 2024

Objetivo: conhecer a percepção dos profissionais de saúde da Atenção Primária à Saúde quanto aos riscos associados ao uso de cosméticos que contêm disruptores endócrinos durante a gestação. Métodos: trata-se de um estudo qualitativo. Os participantes foram 17 profissionais de saúde que fazem consultas às gestantes na Atenção Primária à Saúde. A coleta de dados ocorreu por meio de entrevista semiestruturada. Para a análise das entrevistas, contou-se com a Análise de Conteúdo, e com referenciais teóricos de pesquisadores da área. Resultados: observou-se que há pouco conhecimento da maioria dos participantes sobre o conceito de disruptores endócrinos, os quais relataram pouca segurança para recomendarem, ou não, sobre o uso de cosméticos e produtos de higiene pessoal e, ainda, poucos demonstraram conhecer os riscos que possam apresentar à saúde. Conclusão: os profissionais de saúde mostraram que há uma fragilidade quanto ao seu conhecimento sobre os riscos dos disruptores endócrinos presentes nos cosméticos, e, consequentemente, encontram dificuldades para orientar as gestantes a reduzirem as exposições prejudiciais. Contribuições para a prática: sensibilização dos profissionais para a necessidade constante de atualizações para prestarem aconselhamento com segurança às gestantes.
En Torno A La Legitimidad De La Sustitución De La Constitución De La Corte Constitucional Colombiana: Análisis Desde La Perspectiva Habermasiana
Authors: Molina Montealegre Diego Mauricio
Published: October 2024

Habermas a partir de Facticidad y validez se plantea legitimar el derecho valiéndose de su idea de la racionalidad comunicativa de tipo intersubjetivo, que lleva como consecuencia a proponer la co-originalidad entre derechos subjetivos y soberanía popular a partir del concepto de autolegislación y como consecuencia de ello fundamentar dicha legitimidad en la inclusión de los procesos de formación de la opinión pública como filtro para la toma de las decisiones democráticas. Desde los anteriores baremos Habermas aporta al debate tradicional en torno a la legitimidad del control de constitucionalidad planteado por la tradición de la filosofía política norteamericana como una tensión entre constitucionalismo y soberanía popular; al interpretar el problema como una tensión aparente resuelta con su idea de co-originalidad. La interpretación de Habermas respecto al control de constitucionalidad y la reforma constitucional se centra en la idea de inclusión de procesos de formación de la opinión pública donde el problema se reformula como un problema sobre la racionalidad comunicativa de la decisión constitucional. Sin embargo, la poca claridad del autor sobre cómo debe darse dicho proceso de inclusión, y la excesiva confianza en la racionalidad de dicho mecanismo frente a las amenazas de los intereses particulares de los medios de poder que manipulan y distorsionan el debate público, nos hablan de las limitaciones que presenta todavía dicho modelo.
Tratados De Doble Tributación En Nicaragua Y Sus Efectos En Las Operaciones Económicas Y Financieras De Los Contribuyentes Transnacionales En El País
Authors: Tunnermann Vanegas Lester Javier
Published: October 2024

El presente artículo de investigación se realizó con el objetivo de analizar los efectos jurídicos y económicos que genera la carencia de tratados de doble imposición en Nicaragua, y sus implicaciones en las operaciones económicas, comerciales y financieras de los contribuyentes transnacionales que realizan transacciones en territorio nacional, o con sus partes relacionadas contribuyentes en el país. Se determina el alcance y los efectos de los tratados de doble imposición en materia tributaria y económica, analizando su concepto, estructura, tratamiento jurídico y estándares internacionales. Se expone el régimen del impuesto sobre la renta en las transacciones internacionales, conforme el ordenamiento jurídico nicaragüense, y los efectos adversos que genera su aplicación directa, a los contribuyentes en sus resultados económicos y financieros, en comparación con la aplicación efectiva de tratados de doble imposición, que reduzcan el gravamen de los impuestos locales con base en la normativa tributaria nicaragüense, lo que resulta en un efecto adverso en la economía del país, al no fomentarse la atracción de inversión extranjera directa, particularmente de empresas o grupos transfronterizos que tributen bajo renta mundial, y que buscan eficiencia financiera y tributaria corporativa, lo que reduce la competitividad de Nicaragua, como un país ideal para la recepción de inversión extranjera.
Exploring anesthesia-related complications in pediatric neurosurgery: a comparative analysis of the sitting and park-bench positions
Authors: Radu Oana Maria , Balaci Georgeta Magdalena , Leucuța Daniel Corneliu , Florian Ioan Ștefan
Published: October 2024

Background and aims. The purpose of this study is to analyze the sitting position and the park-bench position for intra-anesthesia complications in pediatric patients undergoing neurosurgery for posterior fossa lesions. Our goal is to highlight the risks associated with each of these positions under general anesthesia to aid in clinical decision making for optimal patient outcomes with regard to postoperative complications.
Methods. We retrospectively reviewed 41 pediatric patients (1 to 18 years old) undergoing posterior fossae surgery in the sitting (32) and park-bench (9) positions between January 2015 and December 2021. The majority of patients (15) who underwent surgery in the sitting position had fourth ventricular tumors (28.12%) and cerebellopontine tumors (18.76%) that required the sitting position.
Results. Of 32 patients operated on in the sitting position, 23 (71.78%) developed anesthetic complications, compared to 8 patients in the park-bench group (88.89%). Venous air embolism occurred in only 6.25% of patients in the sitting group. Compared to the sitting position, no cases of gas embolism were documented in the park-bench position. However, transient episodes of gas embolism cannot be excluded due to the higher incidence of hemodynamic instability (44.44%), need for additional fluid therapy (44.44%) and vasopressor support (11.11%), decreased CO2 (22.22%) and oxygen desaturation (22.22%). Patients who underwent surgery in the sitting position had a longer duration of surgery [247.5 min IQR (172.75 - 325.25)] and a longer duration of anesthesia [331 min IQR (237.5 - 423.25)]. Pneumocephalus (4, 12.5%) and postoperative hematoma (3, 9.38%) were the most common postoperative complications in patients who underwent surgery in the sitting position. In the park-bench group, three patients had postoperative complications, including postoperative hematoma (2, 25%) and hydrocephalus (1, 12.5%).
Conclusions. The incidence of anesthetic complications is lower in the sitting position compared to the park-bench position. Although there was no documented gas embolism in the park-bench position, the lower rate of venous air embolism in the sitting position may suggest a better control or a lower risk in this position. However, the sitting position has a less frequent occurrence of hemodynamic instability than the park-bench position.
Understanding microRNAs in the context of bacterial versus viral infections
Authors: Milhelm Zaki , Chiroi Paul , Harangus Antonia , Dudea Marina , Ciocan Cristina , Pop Laura , Braicu Cornelia , Berindan-Neagoe Ioana
Published: October 2024

Introduction. MicroRNAs (miRNAs), small non-coding RNAs that regulate gene expression, have emerged as biomarkers for differentiating infection types due to their distinct expression profiles in response to pathogens. This study explores miRNA profiling using microarray technology to identify miRNA signatures that differentiate viral from bacterial infections in plasma samples.
Methods. Plasma samples were collected from patients diagnosed with either bacterial (e.g., pneumonia) or viral (e.g., human papillomavirus) infections; control samples were used to evaluate altered miRNA pattern, followed by Ingenuity Pathway Analysis (IPA) analysis.
Results. Microarray analysis revealed distinct miRNA expression patterns for bacterial and viral infections. In bacterial infections, 11 miRNAs were significantly downregulated compared to controls. Similarly, 12 miRNAs were downregulated in viral infections. Pathway analysis indicated that the altered miRNAs in bacterial infections were linked to immune and inflammatory pathways. In contrast, viral infections were associated with miRNAs involved in cellular stress and replication processes.
Conclusion. Plasma miRNA profiling offers a promising diagnostic tool to differentiate bacterial from viral infections, providing specific miRNA signatures underlying immune responses. These findings represent a foundation for developing miRNA-based diagnostics, improving the precision of infection diagnosis, and paving the way for targeted therapeutic interventions.
Improving Time to Goals of Care Discussions in Invasively Ventilated Preterm Infants
Authors: Gentle Samuel J. , Cohen Charli , Carlo Waldemar A. , Winter Lindy , Hallman Madhura
Published: October 2024

BACKGROUND AND OBJECTIVES

The challenge of identifying preterm infants with bronchopulmonary dysplasia (BPD) that need tracheostomy placement may delay goals of care (GOC) discussions. By identifying infants with a low probability of ventilation liberation, timely GOC discussions may reduce the time to tracheostomy. Our SMART aim was to reduce the postmenstrual age (PMA) of GOC discussions by 20% in infants with BPD and prolonged invasive ventilatory requirement by October 2020.

METHODS

Our group conducted a quality improvement initiative at the University of Alabama at Birmingham. Infants were included if born at <32 weeks’ gestation and exposed to invasive ventilation for ≥2 weeks beyond 36 weeks’ PMA. Interventions included (1) consensus of BPD infants at risk for tracheostomy dependence, (2) monthly multidisciplinary tracheostomy meetings, and (3) development and utilization of tracheostomy educational content for families. Statistical process control charts were used for all analyses.

RESULTS

A total of 79 infants were included in analyses, of which 44 infants either received a tracheostomy or died. From X-mR control chart analysis, there was special cause variation in the time to GOC discussions, which decreased from 62 to 51 weeks’ PMA related to monthly multidisciplinary conferences. The average PMA at tracheostomy decreased from 80 weeks to 63 weeks with no change in the frequency of tracheostomy placement or discordant GOC discussions in which infants survived to hospital discharge without a tracheostomy.

CONCLUSIONS

In infants with ventilator-dependent BPD, standardization of GOC discussions reduced the PMA of GOC discussions and tracheostomy.
Preparing Physician–Scientists for the Future of Academic Medicine
Authors: Burns Audrea M. , Moore Daniel J. , Rassbach Caroline E. , Boyer Debra , Gildner Candace , Byrne Bobbi , Harris Kelly W. , Iness Audra , Powell Weston T. , Callaway Danielle , Lajiness Jacquelyn , Forster Catherine S. , Orange Jordan S. , Ackerman Kate G. , Thammasitboon Satid
Published: October 2024

The changing field of academic medicine presents unique challenges for physician–scientists, who intricately weave the complexities of research and patient care. These challenges have significantly lengthened the time needed for scientific discoveries to be applied in clinical practice. In response to these escalating demands, the training trajectory for physician–scientists has notably expanded over recent decades. In anticipation of and preparation for future training requirements, the National Pediatrician-Scientist Collaborative Workgroup facilitated a series of convenings with a diverse array of stakeholders vested in physician–scientist training. The framework Strategic Foresight was used to explore possible future scenarios and develop strategic plans. Seven pivotal themes, termed “performance zones,” emerged from this endeavor: (1) revolution in education through technology-enhanced learning, (2) educational outcomes beyond content mastery, (3) artificial intelligence-empowered research portfolios and expansive networks, (4) evolution of high-performance inclusive, equitable, distributed, and agile teams, (5) evolution of antifragile systems, (6) a multiparadigmatic program of research, and (7) interdependence and commitments to a common agenda for collective impact. These identified zones underscore the imperative for physician–scientists to acquire novel skill sets essential for navigating the impending shifts in the health care landscape. These findings are poised to steer policy initiatives and educational advancements, fortifying the foundation for future physician–scientist training needs.
A Comunhão dos Santos e o chamado universal à santidade na Igreja
Authors: Morbach Cezar Luis
Published: October 2024

Somente Deus é Santo (Ex 19,5), mas Ele fez da santidade um dom para o Seu povo. A Igreja assumiu esse dom e essa missão, motivando seus membros a buscarem a santidade própria da sua índole. Ela o faz através do culto dos santos, já presente nos primeiros séculos da Igreja, bem como através da profissão de fé na Communio Sanctorum do Credo apostólico. A Constituição Dogmática Lumen Gentium do Vaticano II desenvolve o tema da Comunhão dos Santos, ainda que não o apresente com esses termos. Com isso, deseja recordar a unidade da Igreja – peregrina, necessitada de purificação e celeste – e a vocação universal à santidade de todo batizado. Ao apresentar os santos como irmãos e benfeitores, a Constituição convida os fiéis à comunhão com os santos através da oração e intercessão, bem como através do exemplo de tantos homens e mulheres que configuraram suas vidas a Cristo.
A protomariologia paulina
Authors: Gonzaga Waldecir , Da Silva Wellington Cristiano
Published: October 2024

O presente artigo oferece uma análise mariológica de Gl 4,4-5 e busca ressaltar suas contribuições para a fundamentação da fé cristã. Em Gl 4,4-5, encontra-se a mais antiga referência bíblica à mãe de Jesus. Sem mencionar seu nome, o “apóstolo dos gentios” (Rm 11,13) refere-se a Maria de Nazaré no contexto da encarnação do Filho de Deus. A expressão paulina “nascido de mulher” (Gl 4,4) remete à condição humana, em sua precariedade e fragilidade, assumida pelo Filho de Deus. A expressão “nascido sob a lei” (Gl 4,4), por sua vez, indica a origem étnica de Jesus: Ele é filho de uma mulher judia. Gl 4,4-5 serviu de base para as futuras elaborações mariológicas. Os Padres da Igreja recorrem a essa referência paulina para responder às correntes gnósticas e ao nestorianismo. A Carta aos Gálatas indica, indiretamente, a maternidade divina de Maria e a sua colaboração na história da salvação. A mariologia de Paulo é bastante sóbria e, estritamente, cristocêntrica. A análise dessa protomariologia leva à redescoberta dos fundamentos primeiros da mariologia bíblica e sistemática. O artigo, por meio de uma análise narrativa, em um primeiro momento, trata sobre o mistério da encarnação no corpus paulinum e analisa a estrutura quiástica de Gl 4,4-5. Em seguida, aprofunda a compreensão das expressões “nascido de mulher” e “nascido sob a lei”, destaca a importância de Gl 4,4-5, enquanto resposta antecipada ao docetismo e ao nestorianismo, e, por fim, sugere, em Paulo, uma mariologia bíblica elementar.
Trindade e experiência humana
Authors: Borges Teixeira Evilázio Francisco
Published: October 2024

A fé cristã não crê num Deus de “qualquer modo”, mas crê num Deus Tripessoal. A revelação e a fé não se situam fora da experiência humana, caso contrário haveria uma fratura entre experiência e fé. Diante dessa premissa de base, perguntas emergem. Em que medida a fé no Deus uno e trino esclarece os problemas a respeito do ser humano e do mundo? Qual orientação encontra na realidade? Ocupar-se, portanto, da doutrina da Trindade parece não somente sensato, mas também um caminho cheio de prospectivas. Trata-se, sobretudo, de esclarecer a questão de fundo: desde que ponto a fé num Deus uno e trino ilumina e realmente transforma a realidade humana? No que diz respeito ao método, trata-se não só de demonstrar a Trindade como o núcleo da fé cristã, mas também de aprofundar aquela intuição de que na fé trinitária se dá a compreensão, como tal.
Assessment of the Classification of the Northwestern Dialect of the Mari Language from the Perspective of Glottochronology
Authors: Normanskaja Julia  V.
Published: October 2024

Introduction. The classification of the Northwest dialect of the Mari language is currently not entirely clear. According to the Encyclopedia of the Mari El Republic, the “Northwest Mari language exhibits some features of both Hill Mari and Meadow-Eastern Mari languages.” However, G. Bereсzki believed that the Northwest dialect belongs to the Hill Mari language. The aim of the study is to analyze the linguistic similarity assessment of the language of the first Gospel created by Priest S. Bobrovsky (1821) and the dialect of the 20th century according to the data of I. G. Ivanov and G. M. Tuzharov, in relation to the Hill and Meadow Mari languages from the perspective of glottochronology.
Materials and Methods. To assess the proximity of the Northwestern Mari dialect of the 18th–19th centuries to the Meadow and Hill Mari dialects, phonetic isoglosses and glottochronology were analysed. For this purpose, a glossed corpus of the first Gospel was uploaded on LingvoDoc, from which a concordance was created. Proprietary LingvoDoc programs were applied to it for comparative-historical analysis.
Result and Discussion. As a result, it was found that in the 19th century, the first Northwest Mari Gospel showed a lexical similarity of 97% with Meadow Mari and 94% with Hill Mari. In the dictionary compiled in the 20th century, there was already significantly less similarity with both Meadow and Hill languages, but the same pattern persisted: lexically, the Northwest dialect in the 19th century and in the 20th century was closer to Meadow Mari. Kreknin’s and Platunov’s 18th-century dictionary practically matched the Meadow Mari book “Beginnings of Christian Doctrine...” created in the early 19th century, with only one diagnostic position showing double reflection. In the Gospel translated by Priest S. Bobrovsky, three positions already showed reflection typical of the Hill Mari grammar by A. Albinsky.
Conclusion. Therefore, it becomes clear that initially in the 18th century, Northwestern Mari differed little from the Meadow Mari language, while by the 19th century, it had become much closer to the Hill Mari dialect. The materials of the article may be useful for specialists in the Mari and Finno-Ugric languages.
Investment in Agricultural Technology – Impact on Gross Added Value and Employment in the Sector
Authors: Atanasova P.
Published: October 2024

Abstract. The challenges in the Agro sector increase with each passing year. Innovations in agricultural machinery meet the growing needs of this sector of the economy. The purpose of the current article is, on the one hand, to analyze the changes occurring in the sector, to highlight good practices on a global scale, and, on the other hand, to analyze the data regarding the replacement and modernization of agricultural machinery compared to the gross added value for the sector. The analyzed data are at two levels of aggregation: national and regional (district level). Methods of descriptive statistics were used, as well as method analyses taking into account the change in employment in the industry. The provided economic analysis gives a clear idea of the state of the agricultural sector: a decrease in its share in the country's economy, an uneven distribution of agricultural machinery by region, and a decrease in the number of employed persons. The results can be used to improve national policies and programs for the development of the Agriculture, forestry, and fisheries sectors in the Republic of Bulgaria
Termálvíz-visszasajtolás és fenntarthatóság – a visszasajtolási potenciál előrejelzési lehetőségei homokkő rezervoárok esetén
Authors: Markó Ábel , Tóth Marianna , Mádl-Szőnyi Judit
Published: October 2024

A termálvizek visszasajtolása az országos és települési szintű hosszú távú energiabiztonság szempontjából kulcsfontosságú: hozzájárul az energiaforrás fenntartható felhasználásához, megnövelve a beruházások élettartamát. Bár számos potenciális nehézség merül fel, ez nem jelenthet mentséget a visszasajtolás hiányára. A kidolgozott eljárással, a problémák előrejelzésével a visszasajtolási lehetőségek értékelhetők, és – a geotermikus potenciálbecslés részeként – kijelölhetők az arra legalkalmasabb területek. A kutatásban eddig a Zalai-medence mintaterületén regionális hidraulikai, formáció és rezervoártest léptékű értékelést végeztük el: a zalai pannon képződményeknél a nyomásviszonyok nem okoznak problémát, míg a rezervoárlépték jelentős heterogenitást mutat, ami befolyásolja a visszasajtolás hatékonyságát.
The effect of cheese fat content on some physico-chemical, textural properties and volatile aroma components of cheese chips
Authors: Albay Zehra , Akçay Gülsüm , Taplak Gizem , Şimşek Bedia
Published: October 2024

In this study, cheese chips were made using full-fat, half-fat, and non-fat Dil cheeses. Full-fat chips were brighter and yellower. Additionally, full-fat chips were also harder, more fragile (p<0.05), and had better sensory properties. 3-Methylbutanal, pyruvaldehyde, and 2-heptanone were more dominant in full-fat and half-fat chips, while 3-methylbutanal, acetic acid, and carbon disulfide were more dominant in non-fat chips. Cheese’s texture, colour, and general acceptability were negatively affected by lowering of chips fat content. When the fat content needs to be reduced, it can be suggested to manufacture half-fat chips with better levels of acceptability.
Povezanost svojstava vimena i sastava mlijeka s infektivnim bakterijskim uzročnicima supkliničkog mastitisa u malih preživača u odnosu na njihov hematološki profil
Authors: Fouad Saad Mena , Badawi Abdel-Salam Ayah , Saber Abdulkader Mahmoud , Nabil Ramsis Meray , Gomaa Sary Ramadan , Sayed Ibrahim Aml
Published: October 2024

Subclinical mastitis (SCM) is a serious production and financial health issue facing small ruminant farms. Shami dairy does, and Rahmani ewes were chosen for this study. The udder dimensions of the test animals were evaluated, while the taken milk samples were analysed for chemical composition and the somatic cell count (SCC). The presence milk lactate dehydrogenase (LDH) enzyme in milk samples, haemogram and leukogram were determined, too. The incidence of SCM in goats and sheep was 53.33 % and 41.67 %, respectively. In both ovine and caprine milk, there was an increase in LDH concerning the increase in SCC. There was a significant difference (p<0.05) between the decrease in milk fat and lactose contents (%) and the high SCC. The coagulase-negative staphylococci in sheep presented a significant difference in the high protein and low fat content, asymmetrical udder, low udder depth, and increased LDH. SCM in dairy ewes was detected with a rising serum C-reactive protein (CRP), while SCM in goats caused by S. aureus was associated to a reduction in lactose and fat but a high LDH, with a weak udder attachment. The study is considered to compare different diagnostic tools for pinpointing SCM.
UTILIZATION OF SHRIMP HEAD AND FISH BONE MEAL FROM FISHERIES WASTE AS LOCAL FISH FEED INGREDIENTS IN LINGGA
Authors: Agriandini Maulina , Purnamasari Tina , Kartika Nurmayuni , Tartila Shobrina Silmi Qori , Oktary Rini , Pratiwi Lastri , Rahayu Sri Panca
Published: October 2024

The problem faced by fish farmers in Lingga is that the feed is quite expensive and rarely found on the local market. The existence of shrimp heads and fish bones are often found in Dabo as waste from processed shrimp crackers and fish balls that have not been utilized. The research aimed to evaluate the quality of fish feed from local fish meal, shrimp head meal and fish bone meal based on organoleptic, physical, and chemical tests. The treatments tested in this study consist of three threatments, namely: feed A (48%), feed B (35%), and feed C (comercial feed). The organoleptic showed that feed have a fibrous texture, typical coconut aroma, and brown color. The results of water stability showed that feed A (86,50 minutes±1,63), B (87,00 minutes±1,29), C (91,75  minutes±0,96) and dispersion of solids feed A (9,38% ±0,95), B (9,50%±0,71), C (8,63%±0,85). The sinking velocity showed that feed A (3,79 cm/s±0,23), B (3,32 cm/s±0,24), C (4,61 cm/s±0,18). The hardness level of feed A (91,63%±1,38), B (91,38%±2,66), C (94,63%±2,14). The proximate of feed has a moisture of 7,53% (A); 5,28% (B); 6,69% (C), ash of 19,95% (A); 17,85% (B); 12,03% (C), crude protein of 49,07% (A); 36,14% (B); 31,23% (C), crude lipid of 4,28% (A); 4,90% (B); 11,63% (C), and carbohydrate 19,19% (A); 35,84% (B); 38,43% (C). The results of  physical and proximate  indicated that ingredients local feedstuff have the potential as fish feed except moisture and ash.
GROWTH PERFORMANCE AND LIVELIHOOD IN CULTIVATION OF VANNAMEI SHRIMP (Litopenaeus vannamei) IN INTENSIVE TAMBAK PT. ANDULANG SHRIMP FARM SUMENEP, EAST JAVA
Authors: Ritonga Lusiana BR , Arifin M. Zainal , Harijon Teguh , Aonullah Asep Akmal , Bawazir Ach. Faizal Maulana
Published: October 2024

Incentive shrimp farming system has become a farming system adopted by most Indonesian farmers to rapidly increase pond productivity with high stocking densities ranging from 100-300 fish/m2. The study aimed to determine the growth performance and survival rate of Vannamei shrimp culture at PT Andulang Shrimp Farm, Sumenep, East Java with different plot sizes and stocking densities. In the augmentation method, 2 culture plots are used, each with an area of plot D4 (1,932 m2) with a stocking density of 177 fish/m2 and plot F3 (2,600 m2) with a stocking density of 172 fish/m2. In plot D4, the average body weight (ABW) was 26.45 g, the feed conversion ratio (FCR) was 1.63 and the survival rate (SR) was 74.05% with a total harvest tonnage of 4,845.64 kg. In plot F3, the average body weight (ABW) was 26.36 g, the FCR was 1.61 and the SR was 75.42% with a total yield of 6,674.42 kg. A high protein diet contributes to the growth of Vannamei shrimp. Optimal water quality and proper feeding can promote the growth of Vannamei shrimp.
DEVELOPMENT OF STANDARD OPERATING PROCEDURES FOR OPERATING REFRIGERATION MACHINERY ON FISHING VESSELS
Authors: Abrori Muhammad Zaki Latif , Demeianto Bobby , Tumpu Mula , Sandri Muhammad
Published: October 2024

Refrigeration machines in fishery companies are widely used to maintain the quality of seafood products to keep them fresh. These machines are quite complex, so operating them correctly is crucial, as fatal operational errors can lead to the damage of the refrigeration equipment. The absence of written SOPs has the potential for non-standardized operations. Therefore, this article aims to develop Standard Operating Procedures (SOPs) for operating refrigeration machines on fishing vessels. To achieve this goal, data from the refrigeration system is used, and competent machine crew members are involved to obtain valid data. The data obtained is analyzed using a quantitative descriptive method. A proposed design of Standard Operating Procedure (SOP) with a cross-functional flow chart diagram has been produced as a guideline for operating refrigeration machines on fishing vessels. Based on the analysis, this SOP Draft has met the eligibility criteria for use. The SOP this machinery are highly significant in assisting the machine crew in ensuring that the machines are operated in a controlled manner following the correct procedures.
MODELING OF STEADY-STATE LIQUID FILTRATION IN A PIECEWISE INHOMOGENEOUS ELASTIC-POROUS MEDIUM IN THE CLASS OF ALMOST-PERIODIC FUNCTIONS (PLANE PROBLEM)
Authors: Mikishanina E. A.
Published: October 2024

When modeling liquid filtration in a porous medium, it is assumed that the filtration coefficient is constant, as a result of which the solution is simplified and reduced to a boundary value problem for the Laplace equation. In this paper, the almost periodic of Bohr analytical solutions of the plane problem of steady-state liquid filtration in an elastic – porous piecewise inhomogeneous domain are constructed using a generalized discrete Fourier transform . The domain is a strip consisting of several layers (strips) with different elastic and filtration parameters. Assuming that the filtration coefficient of an elastic-porous medium depends on the first invariant of the stress tensor, we consider it linearly dependent on the coordinate varying along the bandwidth. The filtration problem is reduced to solving a system of partial differential equations with specified boundary conditions on the upper and lower boundaries of the entire multilayer strip and conditions on the internal lines of the media interface, which in turn is reduced to solving the Cauchy problem for a system of Bessel ordinary differential equations. All solutions in this paper are obtained in the form of absolutely convergent Bohr-Fourier series, the coefficients of which are expressed in terms of given functions. Fluid filtration in a three-layer strip consisting of various light and sufficiently elastic-porous sedimentary and igneous rock layers is modeled. Graphs of the desired mechanical parameters are constructed. Their convergence to boundary conditions and conditions on the interface lines of media is shown. The paper also provides basic information concerning the properties of almost-periodic functions and the generalized discrete Fourier transform necessary for a more detailed understanding of the problem.
IDENTIFICATION OF STRESS INTENSITY FACTORS, T-STRESSES AND HIGHER-ORDER COEFFICIENTS OF REGULAR TERMS IN THE WILLIAMS SERIES EXPANSION THROUGH MOLECULAR DYNAMICS SIMULATIONS
Authors: Stepanova L. V. , Belova O. N.
Published: October 2024

Molecular dynamics (MD) approach and finite element analysis are enforced for the investigating the stress – strain fields in the proximity of the notch tip in a copper plate with single horizontal and inclined edge notches. The MD simulation embodied in a classical molecular dynamics program Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) is aimed at evaluating conventional continuum linear elastic fracture mechanics key parameters, precisely stress intensity factors (SIF), T-stresses and generalized stress intensity factors (higher order factors) of the Max Williams power series expansion (WE) of the stress field adjacent with the notch tip for pure tensile (Mode I), pure shear (Mode II) and mixed mode (combinations of Mode I and Mode II) loadings of the notched specimen in linear elastic isotropic media. The paramount intent of the research is the comparability of continuum and atomistic procedures for the appraisement of the near notch tip fields exploiting the exemplification of one of the widespread cracked configurations. SIFs, T-stresses and higher order amplitude coefficients of the WE for the single-edge notched Cu plane under Mode I and Mixed Mode loadings are estimated by atomistic and finite element modelling. The wide class of the MD computations in LAMMPS is effectuated. The atomistic values of SIFs and amplitude factors of higher order terms of the WE are correlated with the quantities gained from the numeric solutions obtained by finite element method. It is elucidated that the continuum fracture theory properly characterizes failure and the near notch tip fields even at tremendously limited distances of only few nanometers. The angular stress distributions found from atomic modeling are restored and correlated with the angular behaviours of the stresses obtained from continuum linear elastic fracture theory. The juxtaposition is shown to be in reasonable agreement between two approaches.
DESCRIPTION OF THE EFFECT OF SOFTENING IN ELASTOMERIC COMPOSITES OBSERVED IN TESTS WITH INCREASING STRAIN AMPLITUDE
Authors: Kislitsyn V. D. , Svistkov A. L. , Mokhireva K. A. , Shadrin V. V.
Published: October 2024

This paper presents the results of complex uniaxial mechanical tests conducted to study polymer nanocomposites with SKU-PPL-2102 prepolymer as a matrix. The unfilled elastomer is a structurally heterogeneous material – it has solid domain structures and therefore can be considered as a nanocomposite exhibiting complex mechanical behav-ior. Tests were carried out on the samples prepared of polyurethane without filler and with 0.5 phr of few-layer graphene filler under conditions of increasing deformation cy-cles and long time-delays between changes in the direction of gripper motion. These tests made it possible to monitor the degree of softening in the material subjected to loading and the increase of dissipative losses at different elongation ratios. It was found that, even at low filler content, the mechanical properties of the material changed signifi-cantly. In addition, note that the viscoelastic properties of the materials’ samples manifest themselves insignificantly (i.e., the "trained" materials can be considered elastic with a certain degree of accuracy) during repeated deformations. An elastic potential that is based on the notion of the effective behavior of loaded polymer chains was used to describe the elastic properties of the material taking into account the Mullins softening effect. The viscoelastic behavior of the nanocomposite under study was described in the framework of the previously described thermodynamic model. The Mullins softening effect was taken into account in both elastic and dissipative terms of the Cauchy stress tensor. The obtained data demonstrate that the consideration of this effect has a considerable effect on the dissipative component of the stress tensor.
MODELING OF PRESTRESSED PLATES WITH MATERIAL INHOMOGENEITY, PERFORATIONS AND INCLUSIONS
Authors: Bogachev I. V. , Nedin R. D.
Published: October 2024

In the present article, we propose the model of in-plane oscillations of inhomogeneous prestressed plates, both solid ones and those containing a set of holes and inclusions made of different materials. We treat the plates’ mechanical properties and the prestress tensor components in the considered 2D problem statement as functions of two coordinates. In order to formulate the boundary value problems of steady-state in-plane vibrations of plates, we employ the general linearized formulation for an elastic body under conditions of an initial stress-strain state. The developed vibration model makes it possible to specify an arbitrary type of prestress state in the plate in the form of analytical dependences, as well as numerically, by solving the corresponding static problem, in which prestresses arise as a result of applying some initial load. To implement the finite element (FE) approach to solving the problems, we formulated the weak problem statement by projecting the original governing equations on the field of test displacements satisfying the essential boundary conditions. To increase the accuracy of calculations for plates with holes and inclusions, the local refinement of FE meshes are used. The proposed approach to calculating plate vibrations is implemented as a software package via FreeFem++. A method for assessing the effect of prestress on dynamic plates’ characteristics under various types of loads is described; a comprehensive analysis is carried out to identify the probing modes, frequency ranges and response pickup areas, most sensitive to the prestress changes, for each of the plates. We systematize and generalize the results obtained during the analysis, give a few practical recommendations on the choice of probing modes for each type of the plates considered, allowing to perform the most efficient schemes for identifying the prestress components.
EXACT SOLUTION OF THE PROBLEM OF ACOUSTICS IN AN ARBITRARY MULTILAYER MEDIUM DURING CONTACT INTERACTION WITH A WEDGE SHAPED STAMP
Authors: Babeshko V. A. , Evdokimova O. V. , Babeshko O. M. , Evdokimov V. S.
Published: October 2024

This paper is the first to study the behavior of the exact solution of the contact problem for a wedge-shaped stamp in terms of shape in an anisotropic layered medium. We consider the contact problem of the action of a wedge-shaped, right-angled, rigid stamp on the surface of a multilayer anisotropic medium. The case of a sharp-angled stamp in terms of some transformation is reduced to the one under consideration. The stamp is assumed to act on a multilayer medium without friction. There may be cases of static and dynamic effects caused by harmonic oscillations of the stamp. The main attention is paid to analyzing the surface behavior of an anisotropic layered medium outside the contact zone. Formulas describing the behavior of the surface in the far zone are constructed and an example of calculating the necessary parameters for their application is given. The considered mixed problem is reduced to solving the two-dimensional Wiener – Hopf integral equation, the Fourier transform of the kernel of which represents the ratio of two analytical functions. The isotropic case of the presence of the ratio of two integer functions in the representation of the kernel has recently been investigated by a universal modeling method, which prompted the transition to the little-studied anisotropic case. In spatial contact problems, the study is carried out by numerical methods that are ineffective for anisotropic media. The exact solution could be constructed only in cases of one-dimensional or integral equations reducible to them. Along with static tasks, the method developed in the article allows studying the acoustic properties of the surface outside the contact zone of the stamp with the medium in the dynamic case, which have little-studied specifics of behavior by sectors. The two-dimensional Wiener-Hopf integral equation solved for the first time can be used in problems of radio wave propagations, in the design of the element base of radio electronics, in the problem of strength in mechanics, and in numerous other important areas.
ELASTIC-PLASTIC BEHAVIOR AND FRACTURE OF STRUCTURES WITH LOSS CONCENTRATORS UNDER CYCLIC LOADS
Authors: Bondar V. S. , Abashev D. R. , Fomin D. Ju.
Published: October 2024

The results of experimental and theoretical studies of structures with stress concentrators under cyclic loading are presented. The studies were carried out on cylindrical specimens with an annular undercut under mild cyclic loading. The sample material is bronze alloy BrKh08-Sh. When testing samples using the digital image correlation method, the deformation of the material on the surface of the undercut is measured, which makes it possible to determine the nature of the change in its range from cycle to cycle. For mathematical modeling of elastoplastic behavior and failure of structures with stress concentrators, a variant of the theory of plasticity based on the theory of flow under combined hardening is used. In the chosen plasticity model, a memory surface is introduced that separates the processes of monotonic and cyclic loading. This division allows one to take into account various features of isotropic and anisotropic hardening of the material. Anisotropic hardening is represented as a sum of microstresses of three different types, which make it possible to describe the effects of fitting and stepping out of the elastoplastic hysteresis loop. The plasticity model makes it possible to assess the damaged state of the material based on the kinetic equation of damage accumulation based on the energy principle (the work of microstresses on the field of plastic deformations). The material behavior model is embedded in the finite element software package. Based on the calculation results, cartograms of the accumulated plastic deformation and stress intensity were constructed. Comparison of the results of calculations and experiments on the range of axial deformation, average axial deformation on the surface of the undercut and the cycle of cycles to failure is carried out. It was found that in a structure with a groove with a radius of 0.25 mm in the concentration zone, rigid loading is realized, and with a radius of 1 mm in the concentration zone, soft asymmetric loading with onesided accumulation of deformation (stepping out) is realized. There is a decrease in durability with a decrease in stress concentration due to the different nature of the change in the stressstrain state.
ESTIMATING PARAMETERS OF PERMISSIBLE DEFECTS IN STRUCTURAL FIBERGLASS BASED ON THEORY OF CRITICAL DISTANCES
Authors: Mullahmetov M. N , Lobanov D. S , Melnikova V. A , Yankin A. S
Published: October 2024

In the process of manufacturing products from composite materials, many defects can occur: cracks, chips, scratches, dents, impact defects, air macro inclusions, and others. Such defects can significantly reduce both the static and fatigue resistance of structures. The purpose of this work is to determine the size of defects that do not affect the strength characteristics of products made of STEF composite material using the point and linear approaches of the theory of critical distances. In the course of the work, a series of tensile tests were carried out on flat specimens of STEF structural fiberglass for electrical purposes. In addition to the experiment, numerical simulation of the tensile processes of these specimens was also carried out. The studied specimens were strips without stress concentrators and with a concentrator in the form of V-shaped notches with different rounding radii at the concentrator top and notch depth. The results obtained were used to determine the material constants according to the theory of critical distances. In this case, two approaches of the theory of critical distances were used, i.e. linear and point ones. To analyze the experimental results, finite element models were built using the ANSYS software package; and numerical simulation was carried out, which resulted in the obtained linearized maximum principal stresses on the central line passing through the top of the stress concentrator. Based on the results of the work, the values of the critical distances of the composite were determined, obtained by using the point and linear methods. On the basis of the data obtained, the sizes of permissible defects in the studied fiberglass were established, which do not affect the strength characteristics of the material. The results obtained can be used to predict the strength characteristics of real products with a complex geometry, as well as to diagnose damaged structural elements.
BUILT-IN FIBER-OPTIC MECHANOPHOTOLUMINESCENT SENSOR OF COMPLEX DEFORMED STATE FOR MONITORING VIBRATIONS OF POLYMER COMPOSITE STRUCTURES
Authors: Pan’kov A. A
Published: October 2024

A mathematical model of an embedded fiber-optic mechanical (elastic) photoluminescent (MFL) sensor of a complex stressed-deformed state for monitoring vibrations of polymer compo- site structures has been developed. The sensor includes one or more light guides doped with many spherical MFL nanoparticles (uniformly distributed over the volume of the light guide) of the "core/shell" type. The latter is an elastomechanoluminescent (EML) core with a photoluminescent (FL) shell. Here the EML effect is the light output of the material with its elastic (non-destructive) deformations. The FL-shell of each capsulated particle transforms the informative "internal" ML- radiation of the core into an "external" informative FL-light flux within the light guide. The resulting value of the FL-light flux from all particles is recorded at the output of each light guide. An addi- tional function of the shell is the localization (within the boundaries of each particle) of the infor- mation glow of the EML-core, which, as a result, improves the spatial resolution of the sensor to diagnose significantly heterogeneous (along the length of the sensor) deformation fields. The MFL-sensor is designed to diagnose the components of the harmonic macrodeformation ampli- tude tensor of the local composite region under consideration, i.e. the vicinity of the built-in sen- sor based on the measurement results of informative photoluminescent FL-light fluxes at the outputs from the light guides of the sensor. Control and adjustment of the output (in the working end "input/output" of the sensor) and recorded informative FL-light fluxes is carried out by using a variable input control light flux, in particular, the same for all light guides of the sensor. It was found that in case of using the single "quartz/MFL particle" light guide (pressure sensor), the desired "spectrum" of pressure amplitudes (the density function of the distribution of amplitude values along the longitudinal axis of the sensor) is a solution of the Fredholm integral equation of the 1st kind based on the results of measurements (at the output from the light guide) of the in- formative resulting FL-light flux as a function of the control incoming (ML) light flux flow. The results of the numerical modeling are obtained for the dependence of the light FL flux value on the control ML flux for cases of uniform and non-uniform (but with a "uniform" spectrum) distribu- tions of the diagnosed pressure amplitude value along the sensor length.
BERNOULLI HYPOTHESES IN THE PROBLEM OF BENDING A MECHANICALLY INCOMPRESSIBLE BEAM
Authors: Firsanov V. V
Published: October 2024

The incompressibility condition for an isotropic linearly elastic material seriously restricts the application of the classical hypotheses of the beam bending theory formulated by Bernoulli for small deformations and displacements. At the same time, it is assumed that such a strong kinematic condition as the condition of immutability of volume must be unconditionally fulfilled. The term “mechanical incompressibility” implies the impact on the beam exclusively of a force load, but with thermal action on it, the deformation of the volume change is a function of temperature. Nevertheless, in both of these cases, the condition of mechanical incompressibility may conflict with the classical hypotheses of beam bending, which may lead to the problem degeneration. Therefore, before solving any problem for mechanically incompressible materials, it is necessary to check all hypotheses used and sufficiently justified for conventional materials for compliance with the kinematic condition of volume immutability. In case of inconsistency, it is necessary to build a calculation model based on other hypotheses that do not contradict incompressibility, which will not lead to a serious complication of the tasks being solved. For a bent beam, the Bernoulli model is used, the basis of which is the kinematic hypothesis of a straight normal (the transverse segment after deformation remains straight, orthogonal to the curved axis of the beam and the distances between the points of the segment remain unchanged) and the force hypothesis of the non-compressibility of the beam fibers in the transverse direction. Each of the above hypotheses should be checked for compliance with the condition of immutability of the beam volume when exposed to the surface force bending load. The consideration of transverse deformations is relevant for low-modulus materials and especially for materials with a low shear modulus in the transverse direction. Incompressible materials, as a rule, belong to low-modulus, but this is not their property that is decisive in the analysis of Bernoulli hypotheses.