Showing 702 results for Type of Study: Research
Vikas Ghute, Onkar Ghadge,
Volume 0, Issue 0 (10-2025)
Abstract
Profile monitoring is generally utilized in manufacturing industries to assess the quality of products and detect deviations from normal conditions. This technique has proven to be effective in improving efficiency, productivity and reducing expenses in manufacturing industries. This paper contains a new Modified Group Runs (MGR) based control chart for the monitoring of simple linear profiles. The suggested control chart relies on employing three distinctive MGR control charts in parallel to monitor the parameters of the simple linear regression profile and is named as the MGR Shewhart-3 control chart. Average run length (ARL) criterion is used to assess the effectiveness of MGR Shewhart-3 control chart under shifts of diverse magnitudes in the parameters of the simple linear regression profile model. The simulation findings demonstrated that the performance of the proposed control chart under error standard deviation shifts is uniformly better than mentioned control charts in detecting small to large shifts. For monitoring shifts in the intercept and slope parameter, the proposed MGR Shewhart-3 control chart performs better than the remaining control charts in detecting medium to large shifts. Finally, the implementation of the proposed control chart is illustrated through an example.
El Ghalya Laaroussi, Badr Dakkak, El Hassan Irhirane, Ahmed Bounit,
Volume 0, Issue 0 (10-2025)
Abstract
This article introduces a novel method for solving problems in Systematic Preventive Maintenance (SPM) by combining the Lean approach with the Algorithm for Inventive Problem Solving (ARIZ). The proposed model first uses Lean to define SPM objectives and constraints, then applies ARIZ to resolve identified contradictions. To ensure an optimal compromise between reliability and availability, a tool based on design of experiment was designed to select the most relevant actors at each stage of the preventive maintenance intervention. The applicability of this method is validated through a case study focused on a crucial piece of mining equipment: the bucket-wheel excavator. This study validates a robust model that explains 86.47% of the variability in reliability and 74.33% of the variability in availability. The analysis revealed that Maintenance Level 1 most significantly affects availability, while Maintenance Level 3 has the greatest impact on reliability. Model optimization predicted maximum values of 5.3125 for reliability and 3.3750 for availability. A sensitivity analysis further confirmed the robustness of this optimal solution, demonstrating that our approach provides concrete solutions beyond the limitations of traditional optimization methods.
Tính Nghiêm Văn,
Volume 0, Issue 0 (10-2025)
Abstract
Fuzzy Time Series (FTS), based on fuzzy set theory, models’ data using linguistic labels to handle incomplete data, and has been widely applied in forecasting student enrollment, traffic safety, and energy prices. However, the subjective determination of time intervals and fuzziness parameters reduces prediction accuracy, especially for highly volatile datasets. This study proposes a novel FTS model that employs Particle Swarm Optimization (PSO) to simultaneously optimize the fuzziness parameters of Hedge Algebra (HA) and interval lengths of the universe of discourse, obviating manual tuning. A new defuzzification formula based on fuzzy set indices further enhances forecasting accuracy. Evaluations on University of Alabama enrollments, Belgian traffic accident fatalities, and Vietnamese gasoline prices demonstrate superior performance, with RMSE reductions up to 20-30% over existing methods [e.g., 70.9 for enrollments with 14 intervals], excelling in incomplete data scenarios. This automated and adaptive model improves forecasting performance and supports decision-making not only in education and energy management but also effectively across various domains.
Mahdieh Jafarnejad Shahri, Ali Bonyadi Naeini, Amir Rahmani, Nasser Koleini Mamaghani, Hassan Sadeghi Naeini,
Volume 0, Issue 0 (10-2025)
Abstract
This study explores how aesthetics and ergonomics intersect in product design through a bibliometric analysis of 317 publications. Scopus was used as the data source, and VOSviewer and RStudio were used to draw a scientific knowledge map. Visual analysis was used to sort out the research lineage. The study found that the number of literature within the search scope is increasing, with countries like China and the United States at the forefront. Results show that China leads in research output but has relatively low international collaboration, while Europe and North America demonstrate stronger cross-country networks. The analysis of the keywords demonstrates that ergonomics-related terms are the dominant term in the literature. Aesthetics emerged as an increasingly important theme, yet it is presented as a less integrated area of inquiry. Thematic mapping indicated four important clusters in the literature: ergonomics and human factors, aesthetics and emotional design, technology/simulation tools, and sustainability and innovation. These findings indicate that ergonomics continues to provide the primary conceptual framework of the discipline, while aesthetics and sustainability represent emerging areas of inquiry. The current study contributes to the fields of design theory and practice with a conceptual framework that integrates ergonomics and aesthetics in design, and by outlining policy implications that could lead to collaboration, interdisciplinarity, and sustainable innovation.
Noeroel Widajati, Adellian Nugraha, Ng Yee Guan,
Volume 0, Issue 0 (10-2025)
Abstract
Introduction: Ergonomic hazards in the workplace can lead to complaints of musculoskeletal disorders (MSDs). According to the Global Burden of Disease, in 2019, approximately 1.71 billion people worldwide were affected by musculoskeletal problems. However, studies investigating the association between work duration and Body Mass Index (BMI) with MSD complaints in the manufacturing industry, particularly in developing countries that still rely heavily on labor-intensive systems, remain limited. This study aims to examine the relationship between work duration and BMI with MSD complaints among workers in the manufacturing industry.
Methods: A cross-sectional analytical study was conducted involving 109 manufacturing workers in the production department. Data were collected subjectively through interviews using the Nordic Body Map questionnaire and anthropometric measurements to calculate BMI. The relationship between variables was analyzed using the Chi-Square test with a significance level of α = 0.05.
Results: The study found that the majority of workers had normal work duration or less than 8 hours per day (83.5%), were classified as overweight (58.7%), and reported moderate MSD complaints (58.7%). A significant correlation was found between BMI and MSD complaints (p = 0.017), while no significant correlation was found between work duration and MSD complaints (p = 0.717).
Conclusion: It can be concluded that BMI has a significant correlation with MSD complaints among manufacturing workers. Interventions should focus on weight control, including promoting balanced nutritional intake. However, other potential risk factors such as lifestyle habits, demographic characteristics, and workload should also be considered in future studies.
Norhana Aripin, Fatimah Mahmud, Gusman Nawanir, Suhaidah Hussain, Khai Loon Lee,
Volume 0, Issue 0 (10-2025)
Abstract
This study explores the impact of human factor ergonomics (HFE), considering physical, managerial, psychosocial, and work design factors on manufacturing performance in the SME automotive sector in Malaysia, and investigates the feasibility of hybrid work environments. Using a mixed-method approach, it collected quantitative data through a survey (132 responses) and qualitative data via semi-structured interviews with five informants from SME automotive manufacturers. The analysis supported three hypotheses, indicating that physical, managerial, and work design factors positively affect manufacturing performance, while psychosocial factors do not due to constraints within SMEs. The study also examined how hybrid work environments can enhance the relationship between psychosocial factors and manufacturing performance. Findings suggest that transitioning to hybrid work, especially for non-operational roles, is feasible with the right technology, policies, culture, and training. This research addresses the urgent need for targeted safety efforts in the automotive SME sector and offers practical insights into optimizing productivity while ensuring employee well-being. It contributes valuable insights into the dynamics of hybrid work environments within manufacturing settings, making it a valuable addition to empirical studies in the field.
Rezki Amelia Aminuddin A.p., Hari Purnomo, Hartomo Soewardi,
Volume 0, Issue 0 (10-2025)
Abstract
The rapid digitalization of higher education in Indonesia has transformed teaching practices but also presents serious obstacles to the physical and emotional well-being of lecturers. This study examines the impact of ergonomic policies on lecturer well-being through the integration of macroergonomics and social engineering perspectives and formulates policies for improving lecturer emotional well-being. To collect information, the study used different methods, including a survey of 100 lecturers with established tools like the Positive and Negative Affect Schedule (PANAS), Perceived Stress Scale (PSS), and ergonomic condition assessment, as well as personal insights from interviews with 10 chosen lecturers. The digital training program and the unergonomic work environment significantly contributed to increased levels of stress and emotional exhaustion. Specifically, 60% of lecturers reported back pain, 55% experienced eye strain, and 50% reported high levels of negative affect. Interview results corroborated these issues and revealed a widespread lack of institutional support. The strategy designed was an integrated ergonomic intervention, including furniture adjustments, enhanced digital skills development, and comprehensive mental health support, to improve lecturer productivity and emotional well-being.
Nurul Ain Sofia Che Awang, Nurul Ainun Hamzah, Nurul Izzah Abdul Samad,
Volume 0, Issue 0 (10-2025)
Abstract
Musculoskeletal disorders (MSDs) pose a significant occupational health challenge in dentistry, potentially affecting the health of future dental professionals. This study aimed to assess the prevalence of MSDs among dental students of Universiti Sains Malaysia (USM) and to explore the relationships between MSD occurrence, demographic factors (academic year, gender, and physical activity levels), and ergonomic awareness. Fifty-five dental students participated in the study, responding to validated electronic questionnaires. The results showed a high prevalence of MSDs, especially over 12 months (41.8%) vs. 7 days (14.5%). Most affected areas were the lower back (74.5%), neck (70.9%), shoulders (60.0%), and upper back (54.5%). Female students showed higher prevalence in some regions (p = 0.032), with Year 5 students reporting the highest prevalence (p = 0.046). Ergonomic awareness was high, with 52.7% rating it as good and 47.3% as excellent. These findings highlight the need to integrate thorough ergonomic education and preventive measures into dental curricula, aiming to promote musculoskeletal health and reduce occupational risks for dental students, thereby supporting long-term occupational well-being in their future careers.
F.d. Javanroodi , K. M. Nikbin ,
Volume 17, Issue 3 (9-2006)
Abstract
There is an increasing need to assess the service life of components containing defect which operate at high temperature. This paper describes the current fracture mechanics concepts that are employed to predict cracking of engineering materials at high temperatures under static and cyclic loading. The relationship between these concepts and those of high temperature life assessment methods is also discussed. A model for predicting creep crack growth initiation and growth in terms of C* and the creep uniaxial ductility is presented and it is shown that this model gives good agreement with the experimental results. The effects of cyclic loading on crack growth behaviour are considered and fractography evidence is shown to back a simple cumulative damage concept when dealing with creep/fatigue interaction. Finally a discussion is presented which highlights the important aspect of life assessment methodology for high temperature plant.
H. Yarjiabadi, M. H. Shojaeefard, A.r. Noorpoor, H.yarjiabadi, , M. Habibian , A.r. Noorpoor ,
Volume 17, Issue 3 (9-2006)
Abstract
The hydrocyclone has a very important roll in industrial separation. The consideration of its behavior is very important for design. In this investigation, behavior of water flow and particles trajectory inside a hydrocyclone has been considered by means of numerical and experimental methods, and results have been compared together. To have a numerical simulation, a CFD software was used, and for modeling flow the RNG k – model applied. Finally, the effect of particle size on hydrocyclone performance has been studied. It was found that the grade efficiency and number of particle that exit from underflow of the hydrocyclone is increased when bigger particles is used.
A series of experiments has been carried out in a laboratory with a hydrocyclone. Comparison shows that, there is a good agreement between the CFD models and experimental result.
M. Haghpanahi, H. Pirali ,
Volume 17, Issue 3 (9-2006)
Abstract
Finite element analysis of a tubular T-joint subjected to various loading conditions including pure axial loading, pure in-plane bending (IPB) and different ratios of axial loading to in-plane bending loading has been carried out. This effort has been established to estimate magnitudes of the peak hot spot stresses (HSS) at the brace/chord intersection and to find the corresponding locations as well, since, in reality, offshore tubular structures are subjected to combined loading, and hence fatigue life of these structures is affected by combined loading. Therefore in this paper, at the first step, stress concentration factors (SCFs) for pure axial loading and in-plane bending loading are calculated using different parametric equations and finite element method (FEM). At the next step, the peak HSS distributions around the brace/chord intersection are presented and verified by the results obtained from the API RP2A Code procedure. Also the locations of the peak hot spot stresses which are the critical points in fatigue life assessment have been predicted.
M. M. Shokrieh, R. Rafiee ,
Volume 17, Issue 3 (9-2006)
Abstract
The main goal of this research is to extract the full mechanical properties of stitch biax and triax composite materials which are necessary for finite element analysis, based on limited available experimental data and without performing full static characterization tests. Utilized experimental data are limited to elastic modulus of two 0o and 45o directions. Using presented technique and aforementioned data, mechanical properties of unidirectional fabrics of biax and triax are obtained and consequently mechanical properties of biax and triax composites are calculated. Evaluation of the results proved proper performance of the technique in this research.
M.r. Modarres Razavi, S.h. Seyedein, P.b. Shahabi , S.h Seyedein,
Volume 17, Issue 3 (9-2006)
Abstract
In this paper hemodynamic wall parameters which play an important role to diagnose arterial disease were studied and compared for three different rheology models (Newtonian, Power law and Quemada). Also because of the pulsatile behavior of blood flow the results were obtained for three Womersley numbers which represent the frequencies of the applied pulses. Results show that Quemada model always located between Newtonian and Power law models however its behavior is closer to Power law model. Concerning this behavior and better agreement between Quemada and experimental blood viscosity, it can be expected that Quemada results are more realistic and accurate.
M. Nikian, , M. Naghashzadegan, S. K. Arya ,
Volume 17, Issue 3 (9-2006)
Abstract
The cylinder working fluid mean temperature, rate of heat fluxes to combustion chamber and temperature distribution on combustion chamber surface will be calculated in this research. By simulating thermodynamic cycle of engine, temperature distribution of combustion chamber will be calculated by the Crank-Nicolson method. An implicit finite difference method was used in this code. Special treatments for piston movement and a grid transformation for describing the realistic piston bowl shape were designed and utilized. The results were compared with a finite element method and were verified to be accurate for simplified test problems. In addition, the method was applied to realistic problems of heat transfer in an Isuzu Diesel engine, and gave good agreement with available experimental.
M. H. Shojaeefard, F. A. Boyaghchi , M. B. Ehghaghi ,
Volume 17, Issue 4 (11-2006)
Abstract
In this paper the centrifugal pump performances are tested when handling water and viscous oils as Newtonian fluids. Also, this paper shows a numerical simulation of the three-dimensional fluid flow inside a centrifugal pump. For these numerical simulations the SIMPLEC algorithm is used for solving governing equations of incompressible viscous/turbulent flows through the pump. The k-ε turbulence model is adopted to describe the turbulent flow process. These simulations have been made with a steady calculation using the multiple reference frames (MRF) technique to take into account the impeller- volute interaction. Numerical results are compared with the experimental characteristic curve for each viscous fluid. The data obtained allow the analysis of the main phenomena existent in this pump, such as: head, efficiency and power changes for different operating conditions. Also, the correction factors for oils are obtained from the experiment for part loading (PL), best efficiency point (BEP) and over loading (OL). These results are compared with proposed factors by American Hydraulic Institute (HIS) and Soviet :::union::: (USSR). The comparisons between the numerical and experimental results show good agreement.
Gh. Yari , M. D Jafari ,
Volume 17, Issue 4 (11-2006)
Abstract
Main result of this paper is to derive the exact analytical expressions of information and covariance matrix for multivariate Pareto, Burr and related distributions. These distributions arise as tractable parametric models in reliability, actuarial science, economics, finance and telecommunications. We showed that all the calculations can be obtained from one main moment multidimensional integral whose expression is obtained through some particular change of variables. Indeed, we consider that this calculus technique for that improper integral has its own importance.
A. Shidfar, Ali Zakeri,
Volume 17, Issue 4 (11-2006)
Abstract
This paper considers a linear one dimensional inverse heat conduction problem with non constant thermal diffusivity and two unknown terms in a heated bar with unit length. By using the WKB method, the heat flux at the end of boundary and initial temperature will be approximated, numerically. By choosing a suitable parameter in WKB method the ill-posedness of solution will be improved. Finally, a numerical example will be presented.
M.r. Alirezaee, S.a Mir-Hassani,
Volume 17, Issue 4 (11-2006)
Abstract
In the evaluation of non-efficient units by Data Envelopment Analysis (DEA) referenced Decision Making Units (DMU’s) have an important role. Unfortunately DMU’s with extra ordinary output can lead to a monopoly in a reference set, the fact called abnormality due to the outliers' data. In this paper, we introduce a DEA model for evaluating DMU’s under this circumstance. The layer model can result in a ranking for DMU’s and obtain an improving strategy leading to a better layer.
M. Nadjafikhah, H. R. Salimi Moghaddam ,
Volume 17, Issue 4 (11-2006)
Abstract
In this article, we generalize the concept of the Lie algebra of vector fields to the set of smooth sections of a T-bundle which is by definition a canonical generalization of the concept of a tangent bundle. We define a Lie bracket multiplication on this set so that it becomes a Lie algebra. In the particular case of tangent bundles this Lie algebra coincides with the Lie algebra of vector fields.
A. Aghajani , V. Roomi ,
Volume 18, Issue 1 (1-2007)
Abstract
Abstract: This paper investigates the problem of whether all trajectories of the system and cross the vertical isocline, which is very important for the existence of periodic solutions and oscillation theory. Sufficient conditions are given for all trajectories to cross the vertical isocline.
