scholarly journals Beyond Poiseuille: Preservation Fluid Flow in an Experimental Model

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Saurabh Singh ◽  
Lucy V. Randle ◽  
Paul T. Callaghan ◽  
Christopher J. E. Watson ◽  
Chris J. Callaghan

Poiseuille’s equation describes the relationship between fluid viscosity, pressure, tubing diameter, and flow, yet it is not known if cold organ perfusion systems follow this equation. We investigated these relationships in anex vivomodel and aimed to offer some rationale for equipment selection. Increasing the cannula size from 14 to 20 Fr increased flow rate by a mean (SD) of 13 (12)%. Marshall’s hyperosmolar citrate was three times less viscous than UW solution, but flows were only 45% faster. Doubling the bag pressure led to a mean (SD) flow rate increase of only 19 (13)%, not twice the rate. When external pressure devices were used, 100 mmHg of continuous pressure increased flow by a mean (SD) of 43 (17)% when compared to the same pressure applied initially only. Poiseuille’s equation was not followed; this is most likely due to “slipping” of preservation fluid within the plastic tubing. Cannula size made little difference over the ranges examined; flows are primarily determined by bag pressure and fluid viscosity. External infusor devices require continuous pressurisation to deliver high flow. Future studies examining the impact of perfusion variables on graft outcomes should include detailed equipment descriptions.

2019 ◽  
Vol 11 (8) ◽  
pp. 913 ◽  
Author(s):  
Tuna Kalayci ◽  
Rosa Lasaponara ◽  
John Wainwright ◽  
Nicola Masini

This study provides an evaluation of spectral responses of hollow ways in Upper Mesopotamia. Hollow ways were used for the transportation of animals, carts, and other moving agents for centuries. The aim is to show how the success of spectral indices varies in describing topologically simple features even in a seemingly homogeneous geographic unit. The variation is further highlighted under the changing precipitation regime. The methodology begins with an exploration of the relationship between the date of a multispectral scene and the visibility of hollow ways. The next step is to evaluate the impact of rainfall levels on numerous indices and to quantify spectral contrast. The contrast between a hollow way and its background is evaluated with Welch’s t-test and the association between precipitation regime and spectral responses of hollow ways are investigated with Correspondence Analysis and Fisher’s test. Results highlight an intrinsic relationship between the precipitation regime and the ways in which archaeological features reflects and/or emits electromagnetic energy. Next, the categorization of spectral indices based on different rainfall levels can be used as a guidance in future studies. Finally, the study suggests contrast becomes an even more fruitful concept as one moves from the spatial domain to the spectral domain.


2007 ◽  
Vol 29 (6) ◽  
pp. 677-695 ◽  
Author(s):  
Jossy Mathew

PurposeThe purpose of this paper is to explore the impact of organisational culture on productivity and quality in software organisations, with special reference to India.Design/methodology/approachThe empirical study was done in two phases. The first phase adopts qualitative methodology and examines the significant aspects of organisational culture, productivity, and quality and the nature of the relationship organisational culture has with productivity and quality. The second phase makes a quantitative analysis of this relationship.FindingsThe study develops a range of insights into the way cultural processes tend to influence productivity and quality in people centric and knowledge intensive work contexts such as software.Research limitations/implicationsThis study employed perceptual measures of productivity and quality in the quantitative analysis. Future studies can develop objective criteria, which would facilitate robust quantitative analysis. Future studies should also explore whether the findings of this study have generalisability beyond the Indian context.Practical implicationsThe study provides insights into the management of productivity and quality in contexts where work is characterised by high levels of abstraction and invisibility.Originality/valueThere are very few empirical studies on this relationship in dynamic and sophisticated work contexts such as software and this further contributes to the debate concerning the impact of organisational culture on effectiveness.


2017 ◽  
Vol 139 (7) ◽  
Author(s):  
Julia C. Quindlen ◽  
Burak Güçlü ◽  
Eric A. Schepis ◽  
Victor H. Barocas

The Pacinian corpuscle (PC) is a cutaneous mechanoreceptor that senses low-amplitude, high-frequency vibrations. The PC contains a nerve fiber surrounded by alternating layers of solid lamellae and interlamellar fluid, and this structure is hypothesized to contribute to the PC's role as a band-pass filter for vibrations. In this study, we sought to evaluate the relationship between the PC's material and geometric parameters and its response to vibration. We used a spherical finite element mechanical model based on shell theory and lubrication theory to model the PC's outer core. Specifically, we analyzed the effect of the following structural properties on the PC's frequency sensitivity: lamellar modulus (E), lamellar thickness (h), fluid viscosity (μ), PC outer radius (Ro), and number of lamellae (N). The frequency of peak strain amplification (henceforth “peak frequency”) and frequency range over which strain amplification occurred (henceforth “bandwidth”) increased with lamellar modulus or lamellar thickness and decreased with an increase in fluid viscosity or radius. All five structural parameters were combined into expressions for the relationship between the parameters and peak frequency, ωpeak=1.605×10−6N3.475(Eh/μRo), or bandwidth, B=1.747×10−6N3.951(Eh/μRo). Although further work is needed to understand how mechanical variability contributes to functional variability in PCs and how factors such as PC eccentricity also affect PC behavior, this study provides two simple expressions that can be used to predict the impact of structural or material changes with aging or disease on the frequency response of the PC.


2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hsin-Hsien Liu ◽  
Hsuan-Yi Chou

PurposeBased on mental accounting theory, this study explored whether the comparability of missed and subsequent promotional formats/frames affects inaction inertia.Design/methodology/approachFour experiments with imaginary and incentive-compatible designs were conducted to test the hypotheses.FindingsConsumers are more likely to express inaction inertia after having missed a comparable promotion than after having missed a noncomparable promotion. Devaluation of the promoted target mediates the impact of comparability on inaction inertia, while referent others' actions do not moderate the comparability effect. Finally, when consumers accept a subsequent inferior promotion, they prefer using a different payment format because it reduces comparability of the two promotions.Practical implicationsCompanies should use different promotional formats/frames to reduce comparability and inaction inertia when a new promotion is relatively inferior to a recent previous one. Companies should offer different payment options to help customers actively avoid comparing a current promotion with a missed promotion.Originality/valueThis study provides a more comprehensive conceptual structure for understanding the relationship between psychological comparability and inaction inertia. It provides insights into what actions companies should take to reduce inaction inertia. Furthermore, this study empirically tests the influence of multiple comparison referents, which provides a reference point for future studies on the factors affecting inaction inertia. A new method to examine whether consumers actively avoid comparisons is used, which clarifies the internal mechanism of inaction inertia.


2015 ◽  
Vol 15 (6) ◽  
pp. 1425-1432 ◽  
Author(s):  
C. Salvinelli ◽  
A. C. Elmore

Poor water quality is a major contributing factor to disease in developing countries. Silver-coated ceramic pot filters (CPFs) are a relatively common form of household water treatment system (HWTS) representing an effective and sustainable technology for poor communities. Water production seems to be the major limiting factor of the CPF's lifetime and sustainability since low flow rates do not produce an adequate daily volume of treated water. This paper describes a long-term study of CPF flow rates under controlled conditions using three different water sources. The relationship between water characteristics and flow rate was assessed with the intent of identifying the principal parameters that impact CPF water production. The study concluded that turbidity seems to be the principal indicator in determining CPF lifetime in terms of quantity of treated water. There is no evidence that biological activity also contributes to premature failure of CPFs and the data did not indicate that chemical precipitation is responsible for the filter clogging. Manufacturers commonly conduct initial flow rate tests using clear water as a measure of quality assurance. However, the relationship between initial flow rate and average flow rate during the lifetime of the CPF should be further studied.


2018 ◽  
Vol 67 (9) ◽  
pp. 1918-1939 ◽  
Author(s):  
Erlinda N. Yunus ◽  
Erni Ernawati

Purpose The purpose of this paper is twofold: first, to investigate the relationship between office redesign and employee productivity; and second to highlight the impact of privacy on work productivity across different generations. Design/methodology/approach This study examines open-office policy more comprehensively by integrating socio-behavioral and physical aspects of the office, and by using a mixed-method approach that incorporates most significant change, factor analysis and hierarchical regression analysis. Using a census method, the respondents were all consultants and trainers in an educational institution who were experiencing office design changes from a combi, cellular-like office to a more open, non-territorial office. Findings Three variables emerged as impacts of office redesign perceived by respondents: friendship, collaboration and privacy. Collaboration and privacy exert a positive influence on work productivity, while friendship does not. The relationship between privacy and work productivity is stronger for the Generation Y than for senior employees, namely, the Baby Boomers and Generation X. Research limitations/implications This study examines the impacts of office redesign in one organization. Future studies should advance the findings by empirically testing the theoretical model in broader contexts. Future studies could also enrich the literature by bringing cultural aspects into the discussion and comparing Asian-based and European or Western-based findings. Practical implications For Gen Y employees who prefer freedom, mobility and flexibility to personalization in their workplace, the open office could be a better solution for organizations that aim for both work productivity and efficiency. Originality/value This study provides an empirical value by using a mixed method of qualitative and quantitative research. This study further contrasts the different perspectives of an office redesign between younger and older generations.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hasitha Dinithi Rupasinghe ◽  
Chaminda Wijethilake

Purpose An alignment between financial and operational measures is an essential element to capture the lean productivity improvements enabling supply chain sustainability. With the aim of supporting small and medium-sized enterprises (SMEs) in addressing corporate sustainability challenges, this study aims to examine the impact of leanness on supply chain sustainability, and the moderating role of sustainability control systems (SCS) on the relationship between leanness and supply chain sustainability. Design/methodology/approach Drawing on lean manufacturing and the levers of control framework, survey data was collected from 106 manufacturing SMEs in Sri Lanka. Moderated multiple regression analysis was used to test the proposed hypotheses. Findings The study finds that lean manufacturing practices, such as just-in-time deliveries, quality management, environmental management and employee involvement show a significant positive impact on supply chain sustainability. As proposed, the interactive use of SCS shows a significant, positive moderating impact on the relationship between employee involvement and social supply chain sustainability. The diagnostic use of SCS negatively moderates the relationships between just-in-time deliveries and economic supply chain sustainability, and environmental management and economic supply chain sustainability. However, both interactive and diagnostic uses of SCS do not show any significant moderating impact between lean manufacturing and environmental supply chain sustainability. Research limitations/implications The following limitations should be taken into account in interpreting the results and implications of this study. Firstly, the study refers to supply chain sustainability as environmental, social and economic sustainability. As these concepts represent broader perspectives of sustainability, and no consensus on how to measure has yet been agreed, future studies may focus on other variables that might capture different perspectives of supply chain sustainability. Secondy, future researchers may further extend the role of SCS (including all four control systems – belief, boundary, interactive and diagnostic) in examining the impact of leanness on supply chain sustainability. Thirdly, this study has considered a sample of manufacturing SMEs in the Western province in Sri Lanka. The results should be carefully generalised to other manufacturing organisations in Sri Lanka and beyond. Finally, future studies may also investigate the impact of leanness on supply chain sustainability by using alternative methodologies, such as multiple case studies. Originality/value SMEs are more likely to focus on diagnostic control systems with the aim of promoting economic supply chain sustainability. However, the findings reveal that manufacturing SMEs in the developing country context lack strong SCS to enable supply chain sustainability.


Author(s):  
Sana Jadallah Al- Sheikh Al- Taher    ◽  
  Ahmed Ibrahim Abu Sen

The main goal of this study was to know the impact of the trends of the green human resources management on the creativeness in the industrial sector in Sudan. Based on the human resources theory,the study model was constructed and hypotheses were deducted and tested by a non- probability sample comprised of 330 employees in the industrial sector. The findings showed a reverse relationship between the trends of the green human resources management and creativeness of employees. One of the applied study core was to assist decision- makers to understand the best way for the trends of the green human resources management. The study recommended that the future studies should be conducted on the relationship between the trends of the green human resources management and creativeness.    


2019 ◽  
Vol 44 (2/3) ◽  
pp. 191-207
Author(s):  
Adnan M. Rawashdeh ◽  
Saleh Abdalhameed Tamimi

Purpose The purpose of this study is to investigate the impact of employee perception of training on organizational commitment, and consequently, the impact of organizational commitment on turnover intention. Design/methodology/approach This study adopted a quantitative research design. Data were collected from 302 registered nurses working at Jordanian hospitals using an email survey questionnaire. Using statistical package for the social science analysis of regression to test the hypothesized model. Findings The results suggest a strong relationship between two variables: perceived availability of training and perceived supervisor support for training and organizational commitment. On the other hand, the perceived benefits of training is found to be negatively related to organizational commitment. The study also confirms a strong inverse association between organizational commitment and turnover intention. Research limitations/implications Limitations and suggestions for future studies three as with all research, there are limitations to this work. First, only three employee perceptions of training are investigated in this study to include perceived availability of training, perceived supervisor support for training and perceived benefits of training. Given that employee perceptions of training include a number of factors, future research may consider other factors such as motivation to learn and co-worker support for training (Newman et al., 2011). Second, the study uses a quantitative approach. Future studies may conduct interviews to examine the relationship between the variables. Third, the data came from registered nurses working in hospitals in a single industry; to increase the generalizability of the findings, there is a need for future research in other industries in Jordan. Fourth, other attitudinal constructs in addition to organizational commitment may act as potential mediators in the relationship between employee perception of training and turnover intention. Future studies can include mediating variables such as job satisfaction (Poon, 2004) and trust in management (Whitener, 2001), which may better explain the hypothesized relationships. Finally, the findings cannot be generalized, as there is a possibility of bias because of differences in knowledge of and attitude to perceived training. Practical implications The findings of the present study have implications for theory and practice. At the theoretical level, the current study adds to the body of knowledge on commitment and turnover. Specifically, the current study provides evidence of a strong or weak relationship between employee perception of training, organizational commitment and turnover intention. The research findings verify the applicability of the social exchange theory (Blau, 1964) and the norm of reciprocity (Gouldner, 1960), and concurs with Fishbein and Ajzen’s (1967) model of beliefs, attitude and behavioral intentions in Jordanian hospitals. From the practical aspect, the study findings urge Jordanian hospitals to enhance employee perception of training and correlated development opportunities, so as to fulfill their employees’ needs and expectations in terms of organizational development. Hospitals may achieve this by providing effective and more comprehensive training programs and urging supervisors to motivate their subordinates to participate in these programs (Jehanzeb et al., 2013). This study results also confirm that perceived supervisor support is very significant to the maintenance of organizational commitment. Hospitals need to create an environment in which practicing training is highly motivated by supervisors. While supervisors are required to publicize the availability of training to the nursing workforce (Ha et al., 2014). Furthermore, the study findings reveal no evidence of a link between perceived benefits of training and organizational commitment. The premise behind this result is attributed to the fact that employees believe that the benefits obtained from participating in training activities are very limited (Kadiresan et al., 2015). So, supervisors are requested to raise their awareness of the benefits to be gained from participating in training programs. The role of supervisors here is very important, they should also unfreeze the old concerns of individuals through positive approach by communicating aggressively about the benefits of training. Moreover, hospitals need to focus more on promoting better relations between training and career development (Newman et al., 2011). Finally, the study results suggest that organizational commitment is negatively related to turnover intention. So, to increase organizational commitment, the hospitals’ management should first, design more effective in house training, as well as motivate their nursing workforce, and financially support external training programs that will foster the nurses’ skills and knowledge. Second, create a culture of commitment to reinforce the relationship with nursing workforce and encourage them to consider the hospital as a family to which they belong (Diab and Ajlouni, 2015). Finally, the work and environmental conditions must be improved through the provision of career development and promotion opportunities (Silva and Dias, 2016). Originality/value This study makes a significant theoretical contribution to the literature, as it addresses an essential and not so well researched issue in Jordan a developing Arab country in Middle East. The paper investigates the interaction between employee perceptions of training, organizational commitment and turnover intention of registered nurses in Jordanian Hospitals.


2020 ◽  
Author(s):  
Xiaochen Wang ◽  
Shengfeng Wang ◽  
Yueheng Lan ◽  
Xiaofeng Tao ◽  
Jinghua Xiao

Abstract The pandemic of coronavirus disease 2019(COVID-19) has threatened the social and economic structure all around the world. Generally, COVID-19 has three possible transmission routes, including pre-symptomatic, symptomatic, and asymptomatic transmission, among which the last one has brought a severe challenge for the containment of the disease. One core scientific question is to understand the influence of asymptomatic individuals and of the strength of control measures on the evolution of the disease, particularly on a second outbreak of the disease. To explore these issues, we proposed a novel compartmental model that takes the infection of asymptomatic individuals into account. We get the relationship between asymptomatic individuals and critical strength of control measures theoretically. Furthermore, we verify the reliability of our model and the accuracy of the theoretical analysis by using the real confirmed cases of COVID-19 contamination. Our results, showing the importance of the asymptomatic population on the control measures, would provide useful theoretical reference to the policymakers and fuel future studies of COVID-19.


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