24 research outputs found
Modelling and identification of dynamic systems using modal and spectral data / by Senad A. Burak.
No full textBibliography: leaves 197-206.viii, 210 leaves : ill. ; 30 cm.The objective of this work is to study some new inverse problems related to mechanical systems, typical to the theory of vibration and engineering practice.Thesis (Ph.D.)--University of Adelaide,Dept. of Mechanical Engineering, 199
Sedentary behavior as a public health issue: Ergonomics as a useful tool
No full textBackground: Sedentary behavior carries the risk of musculoskeletal problems, especially in the lumbosacral region of the spinal column. According to modern lifestyle, this has begun to be a public health issue.
Objective: To point to the health risks of working at the computer and present an ergonomic analysis of the typical and improved position of workers in front of the computer, thereby reducing the chances of emergence occupational diseases.
Results: Changing the position of the subjects led to a change in lumbar pressure from 2,818 N/m2 to 351 N/m2. Software analysis of the changed position indicates that this position is acceptable, both for the lumbosacral region of the spine and for the abdominal muscles.
Conclusions: A change in body position will decrease lumbar moment and the load on the lumbosacral region of the spine. Work chair with lumbar support, the right desk height, setting the appropriate position of the monitor, selecting the optimal keyboard and mouse, dividing the workspace into appropriate zones, as well as changing lifestyle and habits should be part of the management of people who spend most of their working time in a sitting position
Numerical simulation of hot forging process in production of axisymmetric automobile parts
No full textThe finite element method were used for the plastic metal flow prediction of ring shaped parts. Various parameters that affect the forging operation are the material characteristics like material strength, ductility, deformation rate, temperature sensitivity and frictional characteristics of the workpiece, preform design, die design and die material. Numerical simulation has been done for axisymmetric automobile parts. The procedure of numerical modeling contains all simulations phases like the movement of preform from inductor to the tool, placement and setting of preform piece inside the tool before the blow in order to get as good result as possible. These techniques are used to reduce the amount of input material for forgings, extend the lifetime of forging dies, and prevent defects in forged components
Postmodern Antigones: Women in Black and the Performance of Involuntary Memory
No full textThe author analyzes how one non-governmental, anti-war organization in Serbia, Women in Black (Žene u crnom) -- a branch of an international feminist and anti-militarist organization -- remembers and commemorates every year the execution of 8,372 Muslim civilians, in a Bosnian town, Srebrenica that took place in July of 1995. The text is departing from an assumption that the act of remembering does not always depend on a stable system of place, but it can also depend on the bodies, and to concentrate on bodily (or incorporated) practices means to question a dominant idea that only written words, or tangible monuments, may be taken as a metaphor for remembering. Therefore, live performances of Women in Black, here and now, with their subversive aesthetics, are seen as a potential threat. Their performances are also turning them into a kind of contemporary Antigones, or anomalous female historians. To be a female historian is not merely to write about the past, it also means binding oneself to the dead, to tell the truth about the suffering of the Other, who is absent, or dead, and cannot speak for himself
Regulating work for other person from standard employment to new forms of work : from standard employment to new forms of work
No full textУ XXI веку радно право нашло се на удару многих чинилаца који су условили промене, од суштинског значаја за правно уређивање положаја радника на тржишту рада. Те нове околности, даље, усложниле су до тада јасно правно уређени радни однос као најзначајнији институт радног права и поделу рада на зависан и независан рад. Самим тим, настала је потреба за реконцептуализацијом кључних појмова који су у најужој вези са радним односом - појмовима запосленог и послодавца. Чиниоци попут дигитализације и аутоматизације рада, као и појава вештачке интелигенције, навели су субјекте тржишта рада да одустану од заснивања радног односа као примарног односа који се заснива поводом рада и да приступе нешто флексибилнијим формама, које, свака у свом домену, напуштају неке од елемената радног односа. До одступања од праксе заснивања радног односа дошло је спонтано, као одговор на све брже промене које се догађају потпомогнуте глобализацијом, појавом интернета и повећаним бројем лица доступних за рад послодавцима. У тим околностима рад у оквиру радног односа може деловати одвраћајуће за послодавце, имајући у виду одредбе закона које предвиђају висок степен заштите запослених, а који подразумева знатне трошкове послодаваца. У раду, ауторка прати еволутивни пут промена кроз који је радни однос прошао, полазећи од појаве рада као друштвене појаве, све до настанка нових форми рада, кључног обележја савременог друштва и тржишта рада XXI века. Ове нове форме представљају крајњи продужетак флексибилизације рада која је довела до „уласка“ независног рада у окриље заштитног радног законодавства, намењеног, пре свега, зависном раду који се обавља под управљачком, номративном и дисциплинском влашћу послодавца. Нудећи могућа решења за приступ редефинисању појмова запосленог и послодавца, у раду се прави основа за уређивање нових форми рада које су још увек невидљиве за многа национална законодавства, укључујући и законодавство Републике Србије.In the 21st century, labor law has come under the influence of numerous factors that have driven changes of fundamental importance to the legal position of workers. These new circumstances have further complicated the clearly regulated employment relationship as the most significant institute of labor law, as well as the distinction between dependent and independent work. Consequently, there has arisen a need to reconceptualize key terms closely tied to the employment relationship - namely, the concepts of employee and employer. Factors such as digitalization and automatisation of work, as well as the emergence of artificial intelligence, have prompted labor market participants to reconsider employment relationships as the primary form of work engagement, and hence, to adopt more flexible forms that, in their respective domains, abandon some elements of the traditional employment relationship. This shift from the practice of forming employment relationships occurred spontaneously, as a response to the increasingly rapid changes facilitated by globalization, internet, and a growing number of individuals available to employers. In such circumstances, employment relationships may seem less appealing to employers, given the legal provisions mandating a high level of employee protection, which entail significant costs for employers. In the dissertation, the author follow the evolutionary trajectory of changes undergone by the employment relationship, starting from the emergence of work as a social phenomenon to the development of new forms of work, a hallmark of 21st-century society and labor markets. These new forms of work represent the ultimate extension of labor flexibilization, which has led to the "entry" of independent work into the protective framework of labor legislation originally designed primarily for dependent work performed under the managerial, normative, and disciplinary authority of the employer. Offering potential solutions for redefining the concepts of employee and employer, the dissertation lays the groundwork for regulating new forms of work that remain invisible to many national legal systems, including the legal framework of the Republic of Serbia
Influence of Different Parameters on Mechanical Characteristics of Wood Welded Assemblies
No full textAn ergonomic analysis and computer simulations of nursing activities while raising the patients in hospitals and nursing homes
No full textBackground: The use of trolleys for transporting the patients and lifting and lowering them in the trolley is a repeated activity in the daily work of a nurse, and a very common cause of the load of the lumbosacral part of the spine and the consequent pathological deformity, and the onset of clinical symptomatology of painful lumbo-sacral syndrome. The high level of excessive biomechanical stress is associated with the established practice of using standard medical wheelchairs to move patients inside the hospital. The process itself depends on the characteristics of the patient, his or her weight, as well as his/her cooperativeness, but primarily depends on the nurse\u27s mobility. Although nurses strive to be in a position that reduces the load on the lumbosacral part of the spine during practice, this is often impracticable due to the patient\u27s inconsistency.
Objective: To present the ergonomic analysis of the medical nurse\u27s workplace while lifting the patient into the wheelchair and to display solution for improving working conditions and prevention of musculoskeletal disorders.
Results: By ergonomic module of this software, we got results that present load on lumbosacral region of spine of medical nurses during their daily activities, especially in the position of lifting and lowering patients. It was concluded that maximal spinal loading decreases significantly and becomes less than critical (3,100 N) in the case of a wheelchair that has ability to automatically lift and lower patient.
Conclusions: The use of hospital wheelchairs with an mechanism for the automatic lifting and lowering of patients and with a sliding seat will reduce the load on the lumbosacral region of the spine, prevent the onset of lumbosacral pain syndrome, facilitates work for the medical nurse and allows nurse to handle the patient on her own. The prevention of lumbosacral pain syndrome improves the quality of work of the nurse and extends the working life. Use of this type of wheelchair is justified in terms of cost-benefit analysis
The optimal design of school desks depending on the height and weight of students
No full textBackground: The subject of this research is the creation of an optimal school bench design with the aim of determining the most favorable posture of students while sitting, taking into account the relevant ergonometric and biomechanical characteristics of the human body. For the proposed model of the school bench which allows adjusting the different slopes of its surface, the corresponding computer model of the student and the table was first created, and then biomechanical and RULA analysis was performed in order to determine the maximum load in the lumbar part. Next, for each test subject of given weight, it was necessary to determine the amount of maximum load in lumbar zone L3/L4 for different slope angles and to determine the critical angles at which the maximum permissible load of 3400 N is reached.
Methods: The analysis is performed on a total of 5 subjects of the same height (180 cm) and various weights (60, 70, 80, 90, 100 kg). The task is to determine at which weight and at what angle of the workbench with standard height will not exceed the permissible loads of the spine, specifically referring to the L4/L5 vertebrae whose stresses should not exceed 3400 N. The CATIA software package (Dassault Systèmes, Vélizy-Villacoublay, France) is used for the analysis. By knowing the anthropometric and work environment data with ergonomic design and analysis, the following analyzes were made: biomechanical analysis, rapid upper limb assessment (RULA) and carry analysis (an option from CATIA software).
Results: The proposed school bench design allows for flexible adjustments to its worktop, that is, changing its tilt. This allows students of different body masses to have an optimal position at work that does not compromise their maximum permissible load in the L4/L5 spinal column (3400N).
Conclusions: The proposed ergonomic design of the desk will result in students being adequately positioned during their activities at school with the minimal risk of permanent deviations and other health problems
Distribution of oxygen consumption by graded loads during ergonometric testing
No full textCardiopulmonary exercise monitoring is a valuable method not only for the evaluation of medical health, but also for the assessment of patients with cardiac or pulmonary dysfunction. Spiroergometry provides additional criteria for the assessment of cardiopulmonary efficiency compared to simple ergometry. Maximal oxygen consumption (VO2max) is the most critical variable during spiroergometry. Most submaximal exercise measures provide the heart rate (HR) response to predetermined workloads in equations or nomograms used to predict VO2max. According to previous studies, the heart rate is divided into five fields. In this paper, we are doing a new redistribution of heart rates-to-workloads into seven fields, corresponding to the ergo bar. In other words, an answer is given based on the initial anthropological values of the subjects, when and in which field there will be a mismatch between the lung capacity of the subjects and the power required for that field
