Fuzzy extensions to Integer Programming models of cell-formation problems in machine scheduling

Cell formation has received much attention from academicians and practitioners because of its strategic importance to modern manufacturing practices. Existing research on cell formation problems using integer programming (IP) has achieved the target of solving problems that simultaneously optimise: (a) cell formation, (b) machine-cell allocation, and (c) part-machine allocation. This paper will present extensions of the IP model where part-machine assignment and cell formation are addressed simultaneously, and also a significant number of constraints together with an enhanced objective function are considered. The main study examines the integration of inter-cell movements of parts and machine set-up costs within the objective function, and also the combination of machine set-up costs associated with parts revisiting a cell when part machine operation sequence is taken into account. The latter feature incorporates a key set of constraints which identify the number of times a part travels back to a cell for a later machine operation. Due to two main drawbacks of IP modelling for cell formation, i.e. (a) only one objective function can be involved and (b) the decision maker is required to specify precisely goals and constraints, fuzzy elements like fuzzy constraints and fuzzy goals will be considered in the proposed model. Overall the paper will not only include an extended and enhanced integer programming model for assessing the performance of cell formation, but also perform a rigorous study of fuzzy integer programming and demonstrate the feasibility of achieving better and faster clustering results using fuzzy theory

The evolution of cell formation problem methodologies based on recent studies (1997-2008): review and directions for future research

This paper presents a literature review of the cell formation (CF) problem concentrating on formulations proposed in the last decade. It refers to a number of solution approaches that have been employed for CF such as mathematical programming, heuristic and metaheuristic methodologies and artificial intelligence strategies. A comparison and evaluation of all methodologies is attempted and some shortcomings are highlighted. Finally, suggestions for future research are proposed useful for CF researchers

Simulation Studies of Ferromagnetic Nematic Fluids

Over forty years ago Brochard and de Gennes predicted the existence of a ferromagnetic nematic liquid crystal phase, characterized by the spontaneous formation of a macroscopic magnetization in the absence of external fields, but only until recently were such states experimentally realized. Renewed interest in this exotic phase of matter may usher a magnetic revolution in liquid crystal physics as an analogue to the wide variety of uses of electro-optical effects using liquid crystals that are sensitive to electric fields. The history of simulation studies and theory of the ferromagnetic nematic fluid is complicated and often limited to determining the existence of such a phase for a variety of models. Recent experimental realizations of the phase necessitate a more thorough theoretical understanding that can address a variety of questions posed by the new results. By further developments on past simulation studies, Monte Carlo simulations of oblate spherocylinders with distributions of dipoles along their surfaces provides a key model for studying the ferromagnetic nematic phase. Long-range electromagnetic interactions are treated using the Ewald summation method, with newly derived modifications for handling distributions of dipoles as opposed to point dipoles. Free energy differences are estimated using the Multiple Bennett Acceptance Ratio(MBAR) method, which are used to calculate the free energy contours in order to construct phase diagrams for the model.</p

Targeted gene expression study of Salmonella enterica during biofilm formation on rocket leaves

In the present study, the ability of Salmonella Typhimurium to form biofilm community on rocket leaves and rocket extract at 10 C and 20 C was investigated. This goal was achieved with the study of expression of genes associated with biofilm formation and other functional roles. The obtained results showed that Salmonella growth was inhibited when cultured in rocket extract (liquid and solid state) and when grew directly to rocket leaves. The observed inhibition might be attributed to nutrient starvation to the specific growth media because of plant leaves's variability, cell physiology and antimicrobial compounds of rocket. In addition, gene expression study using Real-Time PCR showed that biofilm was formatted on solid media, while the entrance and adhesion of the microorganism within the plant held more strongly through the stomata of the plant leaves. Furthermore, genes associated with managing stress situations were overexpressed at 20 C. From these results, it is indicated that further studies are needed to better determine the survival and/or growth of the pathogen as “real” biofilm cells on plants. In addition, the study on development and gene expression of biofilm cells is necessary in order to eliminate the specific pathogen and reduce the food-borne diseases it causes

Oral Health-Related Quality of Life of Greek Adults: A Cross-Sectional Study

Purpose. The aim of the present study was to investigate the impact of oral health status on the quality of life of adults in different regions of Greece, using the Oral Health Impact Profile-short form (OHIP-14). Methods. A random sample consisting of a total of 504 Greek adults between the ages of 35–44 years (mean 39.1 ± 3.5) was selected from different urban and rural areas, and face-to-face interviews were conducted using the validated Greek language OHIP-14. Associations of the total OHIP-14 score and its 7 sub-scales along with the self-perceived quality of life were evaluated with Spearman's correlations. Results. The subjects had an overall weighted OHIP-14 score of 1.1 (sd 1.9). No significant differences were found for either rural or non-metropolitan areas when compared to urban or metropolitan regions. High scores of above 2 were determined for functional limitation, physical pain, handicap, and the psychological discomfort scales. The education level of the subjects had a significant positive impact on the quality of life of the subjects. Conclusions. Dental and oral health conditions are factors that do impact on the quality of life of individuals

How much of the intraaortic balloon volume is displaced toward the coronary circulation?

This is a post-print version of the published article. Copyright @ 2010 The American Association for Thoracic Surgery.This article has been made available through the Brunel Open Access Publishing Fund.Objective: During intraaortic balloon inflation, blood volume is displaced toward the heart (Vtip), traveling retrograde in the descending aorta, passing by the arch vessels, reaching the aortic root (Vroot), and eventually perfusing the coronary circulation (Vcor). Vcor leads to coronary flow augmentation, one of the main benefits of the intraaortic balloon pump. The aim of this study was to assess Vroot and Vcor in vivo and in vitro, respectively. Methods: During intraaortic balloon inflation, Vroot was obtained by integrating over time the aortic root flow signals measured in 10 patients with intraaortic balloon assistance frequencies of 1:1 and 1:2. In a mock circulation system, flow measurements were recorded simultaneously upstream of the intraaortic balloon tip and at each of the arch and coronary branches of a silicone aorta during 1:1 and 1:2 intraaortic balloon support. Integration over time of the flow signals during inflation yielded Vcor and the distribution of Vtip. Results: In patients, Vroot was 6.4% ± 4.8% of the intraaortic balloon volume during 1:1 assistance and 10.0% ± 5.0% during 1:2 assistance. In vitro and with an artificial heart simulating the native heart, Vcor was smaller, 3.7% and 3.8%, respectively. The distribution of Vtip in vitro varied, with less volume displaced toward the arch and coronary branches and more volume stored in the compliant aortic wall when the artificial heart was not operating. Conclusion: The blood volume displaced toward the coronary circulation as the result of intraaortic balloon inflation is a small percentage of the nominal intraaortic balloon volume. Although small, this percentage is still a significant fraction of baseline coronary flow.This article is available through the Open Access Publishing Fund

Validation of a Greek version of the oral health impact profile (OHIP-14) for use among adults

<p>Abstract</p> <p>Background</p> <p>To test the validity of the short form of the Oral Health Impact Profile (OHIP-14) for use among adults in Greece.</p> <p>Methods</p> <p>The original English version of the OHIP-14 was translated using the forward-backward technique, pilot-tested, and then applied to 211 adults aged 35 years and above. The questionnaire was filled out during face-to-face interviews conducted by one dentist, while individuals were asked to undergo a clinical examination. The internal consistency of the questionnaire was evaluated using Cronbach's alpha (α) coefficient and inter-item and item-total correlations. Discriminant and convergent validities were assessed.</p> <p>Results</p> <p>Cronbach's α was estimated to be 0.90. Inter-item correlations coefficients ranged from 0.10 to 0.83, while item-total correlations coefficients from 0.44 to 0.76. Significant associations were found between OHIP-14 and the decayed, missing and filled teeth (DMFT) and oral hygiene, supporting the ability of the questionnaire to discriminate between individuals with and without impacts. The OHIP-14 total score was highly associated with self-perceived oral health status (r_s= 0.57; p = 0.01), as well as with self-assessment of oral satisfaction (r_s= 0.55;p = 0.01). Similar results were observed by investigating the relationship between the latter questions and each domain score as well as in various sub-groups analyses.</p> <p>Conclusions</p> <p>The OHIP-14 is a reliable and valid questionnaire for the assessment of OHRQoL among adults in Greece.</p

Teaching English to Young Learners. International TEYL Research Papers : 2016

This 2016 edition of TEYL research papers contains reports on small-scale classroom-based action research undertaken by post-graduate students for completion of their Master of Arts degree in Teaching English to Young Learners, from the University of York. In this edition, four papers are presented, focussing on: the impact of assessment descriptors on 12-14 year-old English language learners’ written work through increased self-awareness undertaken in Portugal (Diana England); teaching active listening skills to 14-16 year-old Spanish learners of English (John Lavery); the value of songs in the classroom to enhance vocabulary retention with very young learners in Greece (Soultana Papaioannou); the use of DARTs (analysis-directed activities related to text) to develop reading comprehension in 12-13 ESL year-old learners in a South-East Asian science classroom (Mark Anthony Steacy). This edition has been compiled and edited by Kate Gregson from the MATEYL supervisory team at the University of York

Monitoring the growth of Salmonella enterica serovar typhimurium in silico and in situ with a view in gene expression

In the present study, the ability of S. Typhimurium to develop a biofilm community on rocket tissue was investigated at 20°C. The differences on expression of genes associated with several functional roles during growth of S. Typhimurium on rocket extract and rocket tissue regarding a laboratory growth medium (Luria – Bertani broth, LB) was also monitored. The findings of the present study could show that Salmonella reacts as exposed to different types of stress when inoculated to a heat sterile plant extract and plant tissue. However, further studies are needed to better determine the survival and / or growth of these as “real” biofilm cells on plant tissues

The exsolution of Cu particles from doped barium cerate zirconate via barium cuprate intermediate phases

This research was supported by EPSRC research grants EP/R023522/1, EP/T019298/1, EP/R023751/1, EP/L017008/1 the China Scholarship Commission (MW) received financial support from the UK Catalysis Hub funded by EPSRC Grant reference EP/R027129/1.As a low-cost alternative to noble metals, Cu plays an important role in industrial catalysis, such as water-gas shift reaction, methanol or ethanol oxidation, hydrogenation of oils, CO oxidation, among many others. An important step in optimizing Cu catalyst performance is control of nanoparticles size, distribution, and the interface with the support. While proton conducting perovskites can enhance the metal catalytic activity when acting as the support, there has been limited investigation of in situ growth of Cu metal nanoparticles from the proton conductors and its catalytic performance. Here, Cu nanoparticles are tracked exsolved from an A-site-deficient proton-conducting barium cerate-zirconate using scanning electron microscopy, revealing a continuous phase change during exsolution as a function of reduction temperature. Combined with the phase diagram and cell parameter change during reduction, a new exsolution mechanism is proposed for the first time which provides insight into tailoring metal particles interfaces at proton conducting oxide surfaces. Furthermore, the catalytic behavior in the CO oxidation reaction is explored and, it is observed that these new nanostructures can rival state of the art catalysts over long term operation.Publisher PDFPeer reviewe