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Publikacije (33262)

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Enis Muratović, Nedim Pervan, Adil Muminović, Muamer Delić

As surface wear is one of the major failure mechanisms in many applications that include polymer gears, lifetime prediction of polymer gears often requires time-consuming and expensive experimental testing. This study introduces a contact mechanics model for the surface wear prediction of polymer gears. The developed model, which is based on an iterative numerical procedure, employs a boundary element method (BEM) in conjunction with Archard’s wear equation to predict wear depth on contacting tooth surfaces. The wear coefficients, necessary for the model development, have been determined experimentally for Polyoxymethylene (POM) and Polyvinylidene fluoride (PVDF) polymer gear samples by employing an abrasive wear model by the VDI 2736 guidelines for polymer gear design. To fully describe the complex changes in contact topography as the gears wear, the prediction model employs Winkler’s surface formulation used for the computation of the contact pressure distribution and Weber’s model for the computation of wear-induced changes in stiffness components as well as the alterations in the load-sharing factors with corresponding effects on the normal load distribution. The developed contact mechanics model has been validated through experimental testing of steel/polymer engagements after an arbitrary number of load cycles. Based on the comparison of the simulated and experimental results, it can be concluded that the developed model can be used to predict the surface wear of polymer gears, therefore reducing the need to perform experimental testing. One of the major benefits of the developed model is the possibility of assessing and visualizing the numerous contact parameters that simultaneously affect the wear behavior, which can be used to determine the wear patterns of contacting tooth surfaces after a certain number of load cycles, i.e., different lifetime stages of polymer gears.

Jasmina Džino, Salko Kulukčija, Mustafa Humo, Miran Sihirlić, Esad Žuškić, Aldin Šahinagić, Adi Bojičić

In 2004, the Commission for the Preservation of National Monuments declared the "Architectural Complex of Husejnija (Husein-kapetan Gradaščević) Mosque in Gradačac" a national monument of Bosnia and Herzegovina. The mosque belongs to the type of central domed mosque with a portico covered by three small domes. In September/October 2023, cracks were observed on six arches, the capitals of two columns, and the base of one column in the portico of the mosque. Geotechnical investigative works included the creation of three excavations and two boreholes with continuous Standard Penetration Tests (SPT). The excavations reveal layers below the ground level, consisting of a well-bound sandy artificial fill from the ground surface to a depth of 1.35 meters, a layer of poorly bound artificial stony material from 1.35 to 2.45 meters, and a layer of natural clay at greater depths. It is assumed that over time, due to water seepage from the hillside and rainfall runoff from the mosque, there has been a change in the physical-mechanical properties of the foundation soil and partial settling of the portico structure. In addition to the existing channel on two sides of the mosque, a drainage ring around the building and a drainage curtain on the uphill slope have been designed. Also, underpinning of the portico foundations in alternating segments has been designed to strengthen the stone masonry layer and prevent further settling and development of cracks in the portico elements. After the works are completed, a 12-month monitoring period is planned, followed by an analysis and repair of the cracks.

Joseph Kim, Heather Caspers, Ilma Jahic, Mindi TenNapel

The purpose of this study was to explore the organizational climate in a women’s prison from the shared perceptions of correctional staff. This study was part of the Prison Research and Innovation Network (PRIN) project, which began in the fall of 2020. Forty-two correctional staff from a low-medium security women’s prison in the Midwest were interviewed in spring 2021. Thematic analysis was conducted to identify staff’s perceptions of organizational climate in the women’s correctional facility. The themes identified as most important to staff were mental health, correctional practices, job satisfaction, and workplace culture. An item pool was developed from the themes identified, and a newly developed organizational climate survey was administered to 80 correctional staff. Qualitative data point to the issues of staff shortages and mandated overtime work impacting the mental health of staff. In addition, organizational climate and its impact on mental health were examined through multiple logistic regressions. The results indicated that having job promotion opportunities, having daily communication between staff and administration, and staff’s knowledge and awareness of correctional policies were positively associated with mental health. This mixed-methods study contributes to understanding the unique challenges correctional staff face working in women’s correctional facilities.

John J. Reilly, Rachel Andrew, Chalchisa Abdeta, Liane B Azevedo, N. A. Farias, S. Barak, Farid Bardid, Bruno Bizzozero-Peroni et al.

Kenan Demirovic, V. Džemidžić, E. Nakaš

Background/Objectives: The relation between the orthopedic temporomandibular joint (TMJ) instability and temporomandibular disorder (TMD) most commonly remain unrecognized by orthodontists. In this study we aimed to evaluate the dentofacial characteristics and temporomandibular disorder symptomatology of patients with orthopedic instability before and after deprogramming with a stabilization splint. Methods: Sixty patients with the signs and symptoms of TMD were assessed using the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) and underwent stabilization splint therapy to place the condyles in a more stable musculoskeletal position. The extent of condylar displacement was evaluated using the condylar position indicator (CPI). Sixteen angular and linear hard tissue landmarks were traced and compared from lateral cephalograms taken in the maximum intercuspation (MI) position before, and in the centric relation (CR) position after, the splint therapy. Results: Following the splint therapy, the signs and symptoms of TMD were significantly reduced or completely eliminated in more than 90% of patients. Compared with the values registered before the splint therapy, a significant reduction in the mean values of condylar displacement was observed on both sides of the vertical (p < 0.001), horizontal (p < 0.05), and transverse (p < 0.001) planes of space after the splint therapy. A comparison of pre- and post-splint lateral cephalograms revealed that, following the splint therapy, the mandible moved more posteriorly and rotated in a more clockwise direction. Conclusion: In patients with orthopedic instability and the signs and symptoms of TMD, muscle deprogramming with a stabilization splint therapy is highly recommended to improve the health of the temporomandibular joint and masticatory structures and contribute to a more correct orthodontic diagnosis.

Kanita Karaduzovic-Hadziabdic, M. Adilovic, Lu Zhang, A. Lumley, Pranay Shah, Muhammad Shoaib, Venkata Satagopam, P. Srivastava et al.

Dina Lagumdžija, Aida Hamzić Mehmedbašić, D. Jesenković, Bakir Kudić, Dina Kapić, E. Ćosović, Orhan Lepara, Belma Pehlivanović Kelle et al.

The objective of this study was to confirm the effects of curcumin and to investigate the effects of its combination with a reduced dose of rosuvastatin in an adenine-induced model of chronic kidney disease (CKD) and associated dyslipidemia in rats. Renal function and morphology, as well as lipid status, were assessed using laboratory parameters and histopathological analysis. Male Wistar rats (n=36) randomly divided into six groups, were treated for 24 days: normal control (standard diet), CKD control (adenine diet, 0.75% w/w adenine-supplemented diet), curcumin (100 mg/kg/day + adenine diet), rosuvastatin minimal therapeutic dose (MTD) (5 mg/day + adenine diet), rosuvastatin reduced dose (RD, 25% of rosuvastatin MTD + adenine diet), and rosuvastatin RD + curcumin (25% of rosuvastatin MTD + curcumin 100 mg/kg/day + adenine diet) group. While rosuvastatin alone showed only antilipemic action, both curcumin alone and its combination with a reduced dose of rosuvastatin showed better renal protection with lower serum creatinine levels and milder renal morphological alterations, as well as better antilipemic action with lower levels of triglycerides, very low-density lipoprotein (VLDL), and low-density lipoprotein (LDL) cholesterols compared with the levels in CKD control rats. Treatment with curcumin alone also resulted in a significantly higher estimated glomerular filtration rate, lower uric acid levels, and higher high-density lipoprotein (HDL) cholesterol, while the combined therapy additionally resulted in higher serum albumin levels, lower total cholesterol, and both atherogenic and coronary risk indexes compared with CKD control rats. The results of this study confirmed the beneficial effects of curcumin alone and provided new evidence for the beneficial effects of its combination with a reduced dose of rosuvastatin in rats with CKD and associated dyslipidemia.

Valery L Feigin, Melsew Dagne Abate, Yohannes Habtegiorgis Abate, S. ElHafeez, F. Abd-Allah, A. Abdelalim, Atef Abdelkader, M. Abdelmasseh et al.

Ali Gavrankapetanović, Admir Bektešević, Sanela Brzika, Nedim Hasic, Emina Letic, I. Rašić

Abstract Adrenocortical nodular hyperplasia and gastrointestinal stromal tumors are rare conditions, and their simultaneous occurrence in a single patient poses diagnostic and therapeutic challenges. Here, we present the case of a 39-year-old female patient who underwent surgical resection for concurrent adrenocortical nodular hyperplasia and GIST on the posterior part of the gastric fundus. The patient presented with symptoms of hyperaldosteronism and malignant hypertension, leading to the discovery of these two distinct tumors. Preoperative evaluation revealed normal laboratory findings and hormone levels, except for hyperaldosteronism and hypertension. The surgical intervention included left suprarenal gland removal and wedge resection of the gastric tumor. The patient experienced a successful outcome without intraoperative complications and remained normotensive during follow-up visits, with sustaining hormonal balance. This case underscores the importance of multidisciplinary collaboration and tailored surgical planning in managing complex neoplastic conditions.

A. Athmani, Saad Grairia, Hatem Seboui, Asma Khemis, A. Formisano, Naida Ademović

PurposeThe primary goal of this research is to evaluate the seismic performance of Asla Hocine Primary School, a heritage school building in Annaba, Algeria, to prevent additional damage during future earthquakes in the region. The study aims to guide decision-makers in strengthening weak parts or elements in the building, implementing preventive measures and ultimately reducing earthquake disaster risk by mitigating vulnerability.Design/methodology/approachThe research employs the 3Muri software to model the seismic behavior and structural failures of the school’s elements. An integrated multimodal pushover analysis is used to generate the non-linear capacity curve of the school to assess its seismic performance. The seismic demand is determined based on Algerian seismic regulations, with peak ground acceleration derived from a probabilistic seismic hazard analysis of Annaba city for return periods of 100, 200 and 500 years. The study develops three seismic scenarios to evaluate performance levels and expected damage probabilities.FindingsThe study reveals that the Asla Hocine Primary School faces a high risk of damage and potential collapse under the expected seismic hazard of the region. The analysis indicates variable resilience across different seismic return periods (100, 200 and 500 years), with the performance level degrading from life safety to collapse prevention and total collapse under increasing seismic intensity. This underscores the need for targeted structural analysis and potential retrofitting to enhance the building’s seismic robustness.Research limitations/implicationsThe paper encouraged to account for soil-structure interaction in similar studies, as it can significantly affect the overall seismic performance of buildings. Furthermore, conducting out-of-plane analysis when necessary can offer valuable insights into the structural behavior of specific components.Practical implicationsThe insights provided by this study contribute vital data toward conservation efforts and risk mitigation strategies for heritage structures in seismic zones. The findings are intended to guide decision-makers in implementing preventive measures and strengthening weak parts or elements in the studied school building, ultimately reducing earthquake disaster risk by mitigating vulnerability.Originality/valueThis research offers a comprehensive framework for assessing the seismic vulnerability of heritage schools using detailed modeling and analysis. It highlights the importance of considering return periods of seismic events in assessing a building’s seismic performance and provides a deeper understanding of the structural response to seismic stresses at both macrostructural and individual element levels. The study emphasizes the critical need for seismic risk assessment and targeted retrofitting to preserve cultural heritage assets and ensure their continued use.

Alen Ćirić, Šemso Ormanović, Nedim Čović, Denis Čaušević

Soccer coaches, although not prominently featured in the foreground, are essential to the outcomes of the sport. They are key figures between athletes and organizational goals. Choosing, retaining, and developing the greatest athletes is the cornerstone to a successful coaching career. The aim of this study was to develop and validate a questionnaire that was determine the characteristic soccer coaching styles. A experimental study involved the participation of 207 soccer coaches (B, A and PRO UEFA coaching license). The questionnaire comprises 14 themes and consists of 65 items designed to evaluate soccer coaching styles, developed from the updated Leadership Scale for Sport. The validation of the developed instrument in this empirical study was conducted using two procedures: (1) factor analysis (PCA with oblique rotation) and (2) an internal consistency assessment (Scale Reliability Analysis – Cronbach's Alpha). Nineteen significant factors were extracted, and they are as follows: Player contribution to the game system; Cooperation/ Opinions; Implementation of coach's requirements; Teaching; Motivation; Conflict resolution; Informations; Sanction; Expressing an opinion; Error correction at own discretion; Highlighting the good and bad sides of players; Instructions; Team goal setting; Highlighting positivism/ negativism; The coach's personal expectations; Team solutions; Strategy creation; Social support; The influence of the team on coaching decision-making. By analyzing the data, it was determined that “B” football coaches are characterized by the coaching style "positive feedback", “A” soccer coaches by the "training and instructor" and "positive feedback" styles, while “PRO” coaches are characterized by the "positive feedback" style and a slightly lower frequency by the "training and instructor" style. Using only one coaching/leadership style is certainly a limiting factor, as different situations require different coaching approaches.

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