Evaluation of Tightening Process of Reamer Bolts by Cooled Fitting

Author(s):  
Toshimichi Fukuoka ◽  
Masataka Nomura ◽  
Shun Inagaki

Reamer bolts are widely used for the bolted joints subjected to large shear forces. The most important application is the case of clamping rigid flanged shaft couplings which deliver large torques. The body diameter of a reamer bolt is basically equal to the bolt hole diameter. When installing into the joint, reamer bolts are cooled in order to temporarily reduce its diameter for easy insertion. Dry ice or liquefied nitrogen is commonly used to lower the bolt temperature. It is customary in the actual tightening operation that to save working hours, the tightening torque is applied to the reamer bolt while its temperature is still well below the ambient temperature. Accordingly, the reamer bolt inevitably elongates as its temperature increases to the ambient one, which leads to the reduction of axial bolt force. In this paper, an equation of simple form is derived, which can estimate the amount of bolt force reduction occurred during the tightening operation of reamer bolts by cooled fitting. It is shown that the reduction rate in axial bolt stress, per unit of temperature difference between the reamer bolt and the fastened plate, gradually increases as the grip length is increased, ranging from about 1MPa/K to somewhat in excess of 2MPa/K. If the target joint tightened by cooled fitting has an excessive strength, the derived equation is useful from the practical point of view. It can determine the excessive torque that compensates the bolt force reduction due to the elongation during the tightening operation. The effectiveness of the derived equation is demonstrated by experiments. Based on the derived equation and the experimental results, a guide line is proposed to securely tighten reamer bolts using cooled fitting.

Author(s):  
Alessandro Messeri ◽  
Michela Bonafede ◽  
Emma Pietrafesa ◽  
Iole Pinto ◽  
Francesca de’Donato ◽  
...  

The pandemic has been afflicting the planet for over a year and from the occupational point of view, healthcare workers have recorded a substantial increase in working hours. The use of personal protective equipment (PPE), necessary to keep safe from COVID-19 increases the chances of overheating, especially during the summer seasons which, due to climate change, are becoming increasingly warm and prolonged. A web survey was carried out in Italy within the WORKLIMATE project during the summer and early autumn 2020. Analysis of variance (ANOVA) was used to evaluate differences between groups. 191 questionnaires were collected (hospital doctor 38.2%, nurses 33.5%, other healthcare professionals 28.3%). The impact of PPE on the thermal stress perception declared by the interviewees was very high on the body areas directly covered by these devices (78% of workers). Workers who used masks for more than 4 h per day perceived PPE as more uncomfortable (p < 0.001) compared to the others and reported a greater productivity loss (p < 0.001). Furthermore, the study highlighted a high perception of thermal stress among healthcare workers that worn COVID-19-PPE and this enhances the need for appropriate heat health warning systems and response measures addressed to the occupational sector.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yunxin Xu ◽  
Weichao Shi ◽  
Abel Arredondo-Galeana ◽  
Lei Mei ◽  
Yigit Kemal Demirel

AbstractSymbiotic relationships have developed through natural evolution. For example, that of the remora fish attached to the body of a shark. From the remora’s perspective, this could be associated to an increased hydrodynamic efficiency in swimming and this needs to be investigated. To understand the remora's swimming strategy in the attachment state, a systematic study has been conducted using the commercial Computational Fluid Dynamics (CFD) software, STAR-CCM + to analyse and compare the resistance characteristics of the remora in attached swimming conditions. Two fundamental questions are addressed: what is the effect of the developed boundary layer flow and the effect of the adverse pressure gradient on the remora’s hydrodynamic characteristics? According to the results, the resistance of the remora can generally be halved when attached. Besides, the results have also demonstrated that the drag reduction rate increases with the developed boundary layer thickness and can be estimated using the boundary layer thickness ratio and velocity deficit. The paper demonstrates that the most frequent attachment locations are also the areas that provide the maximum drag reduction rate.


2020 ◽  
Vol 11 (01) ◽  
Author(s):  
Ekta . ◽  
Manju Mehta ◽  
Praveen Kumar Sharma

A musculoskeletal disorder is highly dependent on the workplace design. The workers whose job requires repetitive tasks, are more prone to this disorder. Textile industry is one of the labor intensive industries and most of its jobs require continuous engagement with the work. Sewing machine operators in this sector due to workplace design are facing high risk of health issues due to focused attention and static posture of the body. Understanding the health issues linked with continuous working hours and static posture need to be addressed. Both Government and non- government organizations need to be better involved in designing interventions targeting these people and protecting them from such health risks.The present study was conducted in Hisar district from Haryana state in which respondents were selected randomly. Total number of respondents were 60 in which 28 were males and 32 were females with objectives to assess work organization and work space design and to find out the occupational health problems and musculoskeletal symptoms among sewing machine operators. The results showed that maximum numbers of the respondents (68.4%) were took break of fixed duration and (53.4%) respondents were work along with others. Majority (43.3%) respondents were the first experience of MSK symptoms from 7 days to 12 months followed by (33.3%) respondents in 2-3 years.


Author(s):  
Evi Zohar

Continuing the workshop I've given in the WPC Paris (2017), this article elaborates my discussion of the way I interlace Focusing with Differentiation Based Couples Therapy (Megged, 2017) under the systemic view, in order to facilitate processes of change and healing in working with intimate couples. This article presents the theory and rationale of integrating Differentiation (Bowen, 1978; Schnarch, 2009; Megged, 2017) and Focusing (Gendlin, 1981) approaches, and its therapeutic potential in couple's therapy. It is written from the point of view of a practicing professional in order to illustrate the experiential nature and dynamics of the suggested therapeutic path. Differentiation is a key to mutuality. It offers a solution to the central struggle of any long term intimate relationship: balancing two basic life forces - the drive for individuality and the drive for togetherness (Schnarch, 2009). Focusing is a body-oriented process of self-awareness and emotional healing, in which one learns to pay attention to the body and the ‘Felt Sense’, in order to unfold the implicit, keep it in motion at the precise pace it needs for carrying the next step forward (Gendlin, 1996). Combining Focusing and Differentiation perspectives can cultivate the kind of relationship where a conflict can be constructively and successfully held in the inner world of each partner, while taking into consideration the others' well-being. This creates the possibility for two people to build a mutual emotional field, open to changes, permeable and resilient.


2014 ◽  
Vol 2 (3) ◽  
Author(s):  
Redacción CEIICH

<p class="p1">The third number of <span class="s1"><strong>INTER</strong></span><span class="s2"><strong>disciplina </strong></span>underscores this generic reference of <em>Bodies </em>as an approach to a key issue in the understanding of social reality from a humanistic perspective, and to understand, from the social point of view, the contributions of the research in philosophy of the body, cultural history of the anatomy, as well as the approximations queer, feminist theories and the psychoanalytical, and literary studies.</p>


2017 ◽  
Vol 50 (1) ◽  
pp. 101-108
Author(s):  
A.F. Jităreanu ◽  
Elena Leonte ◽  
A. Chiran ◽  
Benedicta Drobotă

Abstract Advertising helps to establish a set of assumptions that the consumer will bring to all other aspects of their engagement with a given brand. Advertising provides tangible evidence of the financial credibility and competitive presence of an organization. Persuasion is becoming more important in advertising. In marketing, persuasive advertising acts to establish wants/motivations and beliefs/attitudes by helping to formulate a conception of the brand as being one which people like those in the target audience would or should prefer. Considering the changes in lifestyle and eating habits of a significant part of the population in urban areas in Romania, the paper aims to analyse how brands manage to differentiate themselves from competitors, to reposition themselves on the market and influence consumers, meeting their increasingly varied needs. Food brands on the Romanian market are trying, lately, to identify new methods of differentiation and new benefits for their buyers. Given that more and more consumers are becoming increasingly concerned about what they eat and the products’ health effects, brands struggle to highlight the fact that their products offer real benefits for the body. The advertisements have become more diversified and underline the positive effects, from the health and well - being point of view, that those foods offer (no additives and preservatives, use of natural ingredients, various vitamins and minerals or the fact that they are dietary). Advertising messages’ diversification is obvious on the Romanian market, in the context of an increasing concern of the population for the growing level of information of some major consumer segments.


Author(s):  
Kuengmi Choi ◽  
Jungil Jun ◽  
Youngshil Ryoo ◽  
Sunmi Park

A bra use can reduce physiological and physical functions because of clothing pressure, which can be a problem for new senior women starting to lose physical function. The present study presents a bra top design development method for promoting new senior women’s physical activity by identifying problems related to bras’ effects on women’s health and minimizing clothing pressure. The analysis utilized the 3D scan data of 42 adult women (age range: 50s) from the 5th Size Korea Project. Bra top design elements were extracted based on new senior consumers’ needs. We developed an average wireframe reflecting the new senior’s physical characteristics, and a standard body form was developed through surface modeling. To produce a consumer-oriented bra with a body shaping effect and reduced clothing pressure that would not affect physical activities, a three-dimensional pattern was developed applying an optimal reduction rate of 80%. To verify the bra’s adequacy for the body form of new senior women, two market-available bras were selected and fit-compared to the developed product. The developed bra received higher expert appearance evaluation and 3D virtual clothing evaluation scores. This study is significant because by using virtual fitting technology, it provides foundational data to quantify the quality of fashion products.


1999 ◽  
Vol 65 (640) ◽  
pp. 4826-4831
Author(s):  
Masayuki NAKAMURA ◽  
Hideaki NAGASHIMA ◽  
Masatomo OONO ◽  
Yoshikatsu ENOKIDA

The following paper is a study of the surface waves caused by a doublet in a uniform stream, and in particular the variation in the pattern with the velocity of the stream or the depth of the doublet. In most recent work on this subject attention has been directed more to the wave resistance, which can be evaluated with less difficulty than is involved in a detailed study of the waves; in fact, it would seem that it is not necessary for that purpose to know the surface elevation completely, but only certain significant terms at large distances from the disturbance. Recent experimental work has shown con­siderable agreement between theoretical expressions for wave resistance and results for ship models of simple form, and attempts have been made at a similar comparison for the surface elevation in the neighbourhood of the ship. In the latter respect it may be necessary to examine expressions for the surface elevation with more care, as they are not quite determinate; any suitable free disturbance may be superposed upon the forced waves. For instance, it is well known that in a frictionless liquid a possible solution is one which gives waves in advance as well as in the rear of the ship, and the practical solution is obtained by superposing free waves which annul those in advance, or by some equivalent artifice. This process is simple and definite for an ideal point disturbance, but for a body of finite size or a distributed disturbance the complete surface elevation in the neighbourhood of the body requires more careful specification as regards the local part due to each element. It had been intended to consider some expressions specially from this point of view, but as the matter stands at present it would entail a very great amount of numerical calculation, and the present paper is limited to a much simpler problem although also involving considerable computation. A horizontal doublet of given moment is at a depth f below the surface of a stream of velocity c ; the surface effect may be described as a local disturbance symmetrical fore and aft of the doublet together with waves to the rear. Two points are made in the following work.


2014 ◽  
Vol 284 ◽  
pp. 60-69
Author(s):  
Mariola Wicka ◽  
◽  
Piotr Chołbiński ◽  
Dorota Kwiatkowska ◽  
Andrzej Pokrywka ◽  
...  

Year on year, one can observe an increase in the use of addictive substances. This leads to occurring the problem of addiction as well as the use of psychoactive substances as a serious hazard to road users. The Regulation of the Minister of Health on agents acting similarly to alcohol and the conditions and manner of conducting research on their presence in the human body, requires adequate benchmarks for performing these tests. An importantfactor, from consultative point of view, is the knowledge of the chemical structure of substances belonging to different groups of drugs of abuse, their metabolic transformations that occur in the body as well as their influence on the body. This is to aid in the proper interpretation of the results of the analytical tests.


Sign in / Sign up

Export Citation Format

Share Document