bluuebunny/crossref_metadata_2025 huggingface dataset:
Dwelling temperatures and comfort during the August 2003 heat wave
Authors: Wright AJ , Young AN , Natarajan S
Published: November 2005

More frequent hot summers in the UK under climate change could lead to increased discomfort in dwellings, but there is little published field data on internal summer temperatures. Temperatures were measured in four dwellings around south Manchester and five dwellings in London during the August 2003 heat wave. Resultant statistics and various comfort metrics indicated a high level of discomfort in most dwellings, particularly in London. Daily internal temperatures were shown to correlate strongly with a time-decaying function of daily outside temperatures. Day and night temperatures were shown to relate to the type of structure. It is concluded that if heat waves become more common, this would lead to increased discomfort, with implications for health, mortality and housing design.

Practical application: The results presented in this paper show what actually happens to a sample of dwelling temperatures during a severe UK heat wave, and the consequences for comfort. Little has been published on this previously. The correlations between time-averaged outside temperatures, and internal temperatures, provide a method for predicting dwelling temperatures in the future in a warming climate, without the need for detailed simulation and including real occupancy effects such as window opening, which are difficult to simulate reliably. Since there were many excess deaths during the August 2003 heat wave, health is an important concern. Work by others on this issue has shown that mortality rate is correlated with a three-day moving average of outside temperature above a threshold. This moving average correlates closely with the type of time-averaged outside temperature used in the paper. It seems quite possible that a 3-day moving average is a good predictor of excess mortality because it is also a good predictor of internal building temperatures, due to the mediation of thermal mass. This provides an alternative, or additional, explanation to that which explains the mortality as the cumulative result of high external temperatures acting on the human body over a few days, without considering the effects of buildings.
A steady-state model for predicting hygrothermal conditions in beds in relation to house dust mite requirements
Authors: Pretlove SEC , Oreszczyn T , Ridley I , Wilkinson T , Crowther D
Published: November 2005

This paper describes the development, testing and validation of a simple steady-state hygrothermal bed model (BED) which predicts conditions of temperature and relative humidity within the bed core (the occupied space between mattress and covering), given the temperature and relative humidity of the bedroom. BED is the second of three simple steady-state models that in combination allow the impact of modifying bedroom hygrothermal conditions on dust mite populations to be assessed. The first of the trio is Condensation Targeter II, an existing validated model that predicts average monthly conditions of temperature and relative humidity within the bedroom. These conditions are then used as boundary conditions for the BED model which predicts hygrothermal conditions within the bed core. Finally, these outputs are in turn used as inputs to a simple Mite Population Index (MPI) model (to be described elsewhere) that predicts their likely effect on house dust mite population growth in the bed. As reported here, BED has been validated using monitored bedroom and bed data for a full year in three dwellings and the results show that the steady state model predicts monthly bed hygrothermal conditions with a reasonable degree of accuracy. Using Condensation Targeter II and BED in combination, a sensitivity study has been carried out to assess the impact of changes in input parameters of both models on hygrothermal conditions in the bed core. This highlights the importance that the design of the fabric and services of the building has on the hygrothermal conditions in a bed. The impact of climate change has also been assessed using future climate change scenarios.

Practical application: This paper describes in detail a simple steady-state model, (BED) which is used to predict the monthly average temperature and relative humidity within a bed, given the ambient conditions within the bedroon. The input parameters, output parameters and the model formulae are provided so that the model can be easily implemented. BED is the second of three simple models that are used to predict, first the bedroon conditions (Condensation Targeter II), second the bed conditions (BED) and finally the likely effect on house dust mite population growth using a simple Mite Population Index (MPI).
Use of an expert system rating for the energy performance of a building
Authors: de Santoli L , Felici G
Published: November 2005

In this paper we present an expert system for the energy performance evaluation of buildings. The system is obtained from the integration of different evaluation methodologies in a unified framework and results in a friendly tool made available to internet users, who can obtain, in real time, good quality performance certificates. The scope of the project is to develop a performance assessment of buildings that is both complete and flexible, and that could be extended to different environmental conditions. The project has been originated from the official European procedure EPBD 2002/91/CE which states the essential requirements in a performance-based building strategy. The expert system designed in the first stage of the project has been embedded in a software tool named BEEPS (Building Environment and Energy Performance System), where a Life Cycle Analysis technique is implemented to provide a material and energy balance over the entire life of the material, product or service. This embodies the knowledge of experts in energy evaluations and makes such knowledge available to users in a comprehensible and concise way. A dynamic set of rules processes the data on the building, draws the proper conclusions and constructs a certificate in textual form combining analysis, motivations and suggestions to improve the energetic efficiency of the considered building. The system has been customized for the production of energy performance certificates of buildings in Italy, taking into account climatic conditions, indoor environment requirements, and cost-effectiveness. Residential premises and winter have been considered in a first stage. In the paper we also describe the validation of the proposed tool on 120 case-studies related to residential real estate built in Rome during the last century. Additional components of the project that strongly contribute to the effectiveness of BEEPS are also described, such as the analysis of the building typology and the use of the Geographical Information System for data gathering. The full system is currently available on-line at www.beepsitalia.it.

Practical application: In this paper an expert system for the energy performance evaluation of buildings is presented. The scope of the study is to develop a tool for the performance assessment of buildings that is both complete and flexible, and that could be extended to different environmental conditions which matchesthe European Directive EPBD 2002/91/CE. The expert system designed has been embedded in a software tool named BEEPS (Building Environment and Energy Performance System), this is available on-line at www.beepsitalia.it.
Strategic design and analysis method of natural ventilation for summer cooling
Authors: Yao R , Steemers K , Baker N
Published: November 2005

A simplified coupled thermal and airflow model has been developed by integrating the British Standard natural ventilation calculation method for a single zone within a four-node thermal resistance network model, which is called the thermal resistance ventilation model (TRV). By comparison of the results from the TRV with that of the ESP-r program, and subsequently tuning the TRV parameter values, good correlation can be obtained. A two-stage method is proposed for natural ventilation strategic design and analysis. The first stage calculates the constant air rate (CAR) and performs parametric studies in order to propose a design strategy and the appropriate opening area which satisfies thermal comfort. The second stage calculates the dynamic air rate (DAR) and internal temperature and performs analytic studies of the proposed design. An example case has been introduced using this two-stage process. It shows that the method proposed in this paper is simple and straightforward and it is suitable for the strategic design of natural ventilation. Furthermore, it demonstrates how the simplified method can be used to generate detailed and robust comfort data based on both an automatic and a behavioural control model.

Practical appilcation: This paper describes a two-stage method to perform parametric and analytic studies of natural ventilation for summer cooling. This method is simple and straightforward, which is suitable for strategic design of natural ventilation. It demonstrates how the simplified method can be used to generate detailed and robust comfort data based on both automatic and behavioural control models.
Changing politics of race and region: Latino migration to the US South
Authors: Winders Jamie
Published: November 2005

Questions and practices of race in the US South have historically been unthinkable outside the register of a black-white binary. In recent years, this connection between the South as a region and race as a dualism has been challenged by Latino migration to southern cities and towns. This article reviews the emerging literature on this southern arm of Latino migration, arguing for more attention to its interactions with racial formations and practices in southern communities and the geographic and place contingency of its features across the region. To achieve more critical understandings of these processes, it suggests, future studies must contextualize this migration in relation to studies of both immigrant gateway cities across the USA and the historical geographies of race and ethnicity in southern cities.
From Military Geography to militarism's geographies: disciplinary engagements with the geographies of militarism and military activities
Authors: Woodward Rachel
Published: November 2005

This paper reviews contemporary approaches in Anglophone human geography to the geographical constitution and expression of militarism and military activities. Three main approaches are identified, and the merits, limitations and insights of each are discussed. These are: traditional Military Geography, intimately associated with state military discourses of military power; a broad political geography, focused on the spatiality of armed conflict; and research from across the social sciences on the political economies and sociocultural geographies of militarism, particularly in nonconflict situations. The paper concludes with some suggestions for further empirical and theoretical inquiry, and argues on moral grounds for a human geography explicitly concerned with military geographies in all their forms.
Places of possibility: where mixed-race partners meet
Authors: Houston Serin , Wright Richard , Ellis Mark , Holloway Steven , Hudson Margaret
Published: November 2005

Although mixed-race partnering in the United States is on the rise, scholars have paid scant attention to where people of `differently racialized parentage' (Ifekwunigwe, 2001: 46) actually meet. In an effort to help fill this gap, this paper (1) offers an overview of current scholarship on places of encounter and (2) aims to provide a blueprint for future research that will explicitly interrogate where mixed-race partners meet. We organize our survey around four contexts—residential neighborhoods, workplaces, educational settings, and cyberspace—to point out productive avenues for further inquiry. In contrast to much of the literature cited in this essay and in an effort to emphasize the intersections of race and space, we advocate for new scholarship that addresses the times and places where routine, prosaic, interactions between adults can erode long-standing stereotypes and lead to meaningful relationships. In studying everyday social and spatial processes, we highlight the potential insights gained from detailing the `micro-geographies of habitual practice' (Nash, 2000: 656).
Factors Affecting Older African American Women's Decisions to Join the PLCO Cancer Screening Trial
Authors: Trauth Jeanette M. , Jernigan Jan C. , Siminoff Laura A. , Musa Donald , Neal-Ferguson Derietra , Weissfeld Joel
Published: November 2005

Purpose

The purpose of this study is to describe the factors associated with the decisions of older African American women to join the PLCO (Prostate, Lung, Colorectal and Ovarian) Cancer Screening Trial when recruited.

Methods

African American women between ages 55 and 74 years who were never diagnosed with a PLCO cancer were eligible for our study. Two methods of recruitment were used. First, mailings were sent to a random sample of women describing the PLCO followed by a telephone call to determine interest in the PLCO. If women were not interested in PLCO but consented to participate in our study, they were interviewed immediately. Second, we followed up with African American women who responded to mass mailings sent out before the start of our study by the Pittsburgh PLCO office. Women completed an interview about their cancer and clinical trial knowledge, attitudes, beliefs, and behaviors. The responses of women who joined the PLCO Trial are contrasted with the responses of women who did not join.

Results

Numerous factors were associated with the decision of older African American women to join the PLCO, including perceptions of cancer prevention and detection, the experience of having a loved one with cancer, knowledge of and experience with clinical trials, and beliefs regarding the benefits and risks of clinical trial participation.

Conclusion

Minority recruitment to cancer clinical trials could be increased by designing interventions focused on individual, organizational, and community needs.
Early Variations of Circulating Interleukin-6 and Interleukin-10 Levels During Thoracic Radiotherapy Are Predictive for Radiation Pneumonitis
Authors: Arpin Dominique , Perol David , Blay Jean-Yves , Falchero Lionel , Claude Line , Vuillermoz-Blas Sylvie , Martel-Lafay Isabelle , Ginestet Chantal , Alberti Laurent , Nosov Dimitri , Etienne-Mastroianni Bénédicte , Cottin Vincent , Perol Maurice , Guerin Jean-Claude , Cordier Jean-François , Carrie Christian
Published: November 2005

Purpose

To investigate variations of circulating serum levels of interleukin-6 (IL-6), tumor necrosis factor alpha (TNFα), and interleukin-10 (IL-10) during three-dimensional conformal radiation therapy (3D-CRT) in patients with non–small-cell lung cancer and correlate these variations with the occurrence of radiation pneumonitis.

Patients and Methods

Ninety-six patients receiving 3D-CRT for stage I to III disease were evaluated prospectively. Circulating cytokine levels were determined before, every 2 weeks during, and at the end of treatment. Radiation pneumonitis was evaluated prospectively between 6 and 8 weeks after 3D-CRT. The predictive value of clinical, dosimetric, and biologic (cytokine levels) factors was evaluated both in univariate and multivariate analyses.

Results

Forty patients (44%) experienced score 1 or more radiation pneumonitis. No association was found between baseline cytokine levels and the risk of radiation pneumonitis. In the whole population, mean levels of TNFα, IL-6, and IL-10 remained stable during radiotherapy. IL-6 levels were significantly higher (P = .047) during 3D-CRT in patients with radiation pneumonitis. In the multivariate analysis, covariations of IL-6 and IL-10 levels during the first 2 weeks of 3D-CRT were evidenced as independently predictive of radiation pneumonitis in this series (P = .011).

Conclusion

Early variations of circulating IL-6 and IL-10 levels during 3D-CRT are significantly associated with the risk of radiation pneumonitis. Variations of circulating IL-6 and IL-10 levels during 3D-CRT may serve as independent predictive factors for this complication.
Phase III Randomized Trial of Cisplatin Plus Placebo Compared With Cisplatin Plus Cetuximab in Metastatic/Recurrent Head and Neck Cancer: An Eastern Cooperative Oncology Group Study
Authors: Burtness Barbara , Goldwasser Meredith A. , Flood William , Mattar Bassam , Forastiere Arlene A.
Published: November 2005

Purpose

Therapy of recurrent/metastatic squamous cell carcinoma of the head and neck results in median progression-free survival (PFS) of 2 months. These cancers are rich in epidermal growth factor receptor (EGFR). We wished to determine whether the addition of cetuximab, which inhibits activation of EGFR, would improve PFS.

Patients and Methods

Patients with recurrent/metastatic squamous cell carcinoma of the head and neck were randomly assigned to receive cisplatin every 4 weeks, with weekly cetuximab (arm A) or placebo (arm B). Tumor tissue was assayed for EGFR expression by immunohistochemistry. The primary end point was PFS. Secondary end points of interest were response rate, toxicity, overall survival, and correlation of EGFR with clinical end points.

Results

There were 117 analyzable patients enrolled. Median PFS was 2.7 months for arm B and 4.2 months for arm A. The hazard ratio for progression of arm A to arm B was 0.78 (95% CI, 0.54 to 1.12). Median overall survival was 8.0 months for arm B and 9.2 months for arm A (P = .21). The hazard ratio for survival by skin toxicity in cetuximab-treated patients was 0.42 (95% CI, 0.21 to 0.86). Objective response rate was 26% for arm A and 10% for arm B (P = .03). Enhancement of response was greater for patients with EGFR staining present in less than 80% of cells.

Conclusion

Addition of cetuximab to cisplatin significantly improves response rate. There was a survival advantage for the development of rash. Progression-free and overall survival were not significantly improved by the addition of cetuximab in this study.
Osteonecrosis of the Jaw in Cancer After Treatment With Bisphosphonates: Incidence and Risk Factors
Authors: Bamias Aristotle , Kastritis Efstathios , Bamia Christina , Moulopoulos Lia A. , Melakopoulos Ioannis , Bozas George , Koutsoukou Vassiliki , Gika Dimitra , Anagnostopoulos Athanasios , Papadimitriou Christos , Terpos Evagelos , Dimopoulos Meletios A.
Published: November 2005

Purpose

Osteonecrosis of the jaw (ONJ) has been associated recently with the use of pamidronate and zoledronic acid. We studied the incidence, characteristics, and risk factors for the development of ONJ among patients treated with bisphosphonates for bone metastases.

Patients and Methods

ONJ was assessed prospectively since July 2003. The first bisphosphonate treatment among patients with ONJ was administered in 1997. Two hundred fifty-two patients who received bisphosphonates since January 1997 were included in this analysis.

Results

Seventeen patients (6.7%) developed ONJ: 11 of 111 (9.9%) with multiple myeloma, two of 70 (2.9%) with breast cancer, three of 46 (6.5%) with prostate cancer, and one of 25 (4%) with other neoplasms (P = .289). The median number of treatment cycles and time of exposure to bisphosphonates were 35 infusions and 39.3 months for patients with ONJ compared with 15 infusions (P < .001) and 19 months (P = .001), respectively, for patients with no ONJ. The incidence of ONJ increased with time to exposure from 1.5% among patients treated for 4 to 12 months to 7.7% for treatment of 37 to 48 months. The cumulative hazard was significantly higher with zoledronic acid compared with pamidronate alone or pamidronate and zoledronic acid sequentially (P < .001). All but two patients with ONJ had a history of dental procedures within the last year or use of dentures.

Conclusion

The use of bisphosphonates seems to be associated with the development of ONJ. Length of exposure seems to be the most important risk factor for this complication. The type of bisphosphonate may play a role and previous dental procedures may be a precipitating factor.
Colon Cancer Survival Is Associated With Decreasing Ratio of Metastatic to Examined Lymph Nodes
Authors: Berger Adam C. , Sigurdson Elin R. , LeVoyer Thomas , Hanlon Alexandra , Mayer Robert J. , Macdonald John S. , Catalano Paul J. , Haller Daniel G.
Published: November 2005

Purpose

Colorectal cancer is the second leading cause of cancer deaths in the United States, with poor survival predicted by regional lymph node (LN) metastasis. The impact of LN ratio (LNR) on survival is unknown in this disease.

Patients and Methods

We analyzed data from Intergroup trial 0089 of adjuvant chemotherapy for stage II and III patients with colon cancer, in which all patients received fluorouracil-based therapy. Survival was similar for all arms of the study, allowing us to evaluate all patients together. End points included overall survival (OS), cancer-specific survival (CSS), and disease-free survival (DFS). Multivariate analyses were performed on all patients and on groups according to LNR quartiles (LNR: < 0.05, 0.05 to 0.19, 0.2 to 0.39, and 0.4 to 1.0). Covariates included in the models were age, sex, tumor stage, grade, histology, number of positive LNs, number of LNs removed, and LNR.

Results

The median age was 63.7 years, and the median number of LNs removed was 11. In the multivariate analysis, LNR was a significant factor for OS, DFS, and CSS in patients with 10 to 15 LN and more than 15 LN removed but not for patients with less than 10 LN removed. Using quartiles, LNR maintained its significance for all three end points when patients were grouped by node status.

Conclusion

After curative resection for colorectal cancer, the LNR is an important prognostic factor and should be used in stratification schemes for future clinical trials investigating adjuvant treatments.
Testicular Edema Is Associated with Spermatogonial Arrest in Irradiated Rats
Authors: Porter Karen L. , Shetty Gunapala , Meistrich Marvin L.
Published: November 2005

Irradiation of LBNF1 rat testes induces arrest of spermatogonial differentiation, which can be reversed by suppression of testosterone with GnRH antagonist treatment. The cause of the arrest is unknown. We investigated the time course and hormonal effects on radiation-induced arrest and changes in interstitial fluid volume. We postulated that the edema evident in irradiated testes caused the differentiation blockade. Rat testes were irradiated with 3.5 or 6 Gy. Interstitial fluid testosterone (IFT) increased between 2 and 6 wk after irradiation, followed by increased interstitial fluid volume at 6 wk and spermatogonial blockade at 8 wk. Additional rats irradiated with 6 Gy were given GnRH antagonist, alone or with exogenous testosterone, for 8 wk starting at 15 wk after irradiation. In rats treated with GnRH antagonist, IFT started falling within 1 wk of treatment, followed by interstitial fluid volume decreases at wk 2 and 3, with recovery of spermatogenesis starting at wk 4. Addition of exogenous testosterone largely blocked the effects of GnRH antagonist on IFT, interstitial fluid volume, and spermatogenesis. Thus the testicular edema was largely modulated by intratesticular testosterone levels. The time course of changes in the spermatogonial blockade more closely followed that of the testicular edema than of IFT, indicating that testosterone may block spermatogonial differentiation indirectly by producing edema. This conclusion was further supported by an experiment in which irradiated rats were treated with GnRH antagonist plus estrogen; the treatment further reduced IFT and interstitial fluid volume and reduced the time to initiation of recovery of spermatogonial differentiation. These results suggest that studies of the edematous process or composition of the fluid would help elucidate the mechanism of spermatogonial arrest in toxicant-treated rats.
Vg1 is an essential signaling molecule inXenopusdevelopment
Authors: Birsoy Bilge , Kofron Matt , Schaible Kyle , Wylie Chris , Heasman Janet
Published: November 2005

Xenopus Vg1, a transforming growth factor β (Tgfβ)family member, was one of the first maternally localized mRNAs identified in vertebrates. Its restriction to the vegetal pole of the egg made it the ideal candidate to be the mesoderm-inducing signal released by vegetal cells, but its function in vivo has never been resolved. We show that Vg1 is essential for Xenopus embryonic development, and is required for mesoderm induction and for the expression of several key Bmp antagonists. Although the original Vg1 transcript does not rescue Vg1-depleted embryos, we report that a second allele is effective. This work resolves the mystery of Vg1 function,and shows it to be an essential maternal regulator of embryonic patterning.
MAP kinase subcellular localization controls both pattern and proliferation in the developingDrosophilawing
Authors: Marenda Daniel R. , Vrailas Alysia D. , Rodrigues Aloma B. , Cook Summer , Powers Maureen A. , Lorenzen James A. , Perkins Lizabeth A. , Moses Kevin
Published: November 2005

Mitogen-activated protein kinases (MAPKs) phosphorylate target proteins in both the cytoplasm and nucleus, and a strong correlation exists between the subcellular localization of MAPK and resulting cellular responses. It was thought that MAPK phosphorylation was always followed by rapid nuclear translocation. However, we and others have found that MAPK phosphorylation is not always sufficient for nuclear translocation in vivo. In the developing Drosophila wing, MAPK-mediated signaling is required both for patterning and for cell proliferation, although the mechanism of this differential control is not fully understood. Here, we show that phosphorylated MAPK (pMAPK) is held in the cytoplasm in differentiating larval and pupal wing vein cells, and we show that this cytoplasmic hold is required for vein cell fate. At the same time, we show that MAPK does move into the nucleus of other wing cells where it promotes cell proliferation. We propose a novel Ras pathway bifurcation in Drosophila and our results suggest a mechanism by which MAPK phosphorylation can signal two different cellular outcomes (differentiation versus proliferation) based on the subcellular localization of MAPK.
IncreasingFgf4expression in the mouse limb bud causes polysyndactyly and rescues the skeletal defects that result from loss ofFgf8function
Authors: Lu Pengfei , Minowada George , Martin Gail R.
Published: November 2005

A major function of the limb bud apical ectodermal ridge (AER) is to produce fibroblast growth factors (FGFs) that signal to the underlying mesenchyme. Previous studies have suggested that of the four FGF genes specifically expressed in the mouse AER, Fgf8 is unique not only in its expression pattern, but also because it is the only such FGF gene that causes limb skeletal abnormalities when individually inactivated. However,when both Fgf8 and Fgf4 are simultaneously inactivated in the AER, the limb does not develop. One possible explanation for these observations is that although both of these FGF family members contribute to limb development, Fgf8 has functions that Fgf4 cannot perform. To test this hypothesis, we used a novel method to substitute Fgf4 for Fgf8 expression in the developing limb bud by concomitantly activating a conditional Fgf4 gain-of-function allele and inactivating an Fgf8 loss-of-function allele in the same cells via Cre-mediated recombination. Our data show that when Fgf4 is expressed in place of Fgf8, all of the skeletal defects caused by inactivation of Fgf8 are rescued, conclusively demonstrating that FGF4 can functionally replace FGF8 in limb skeletal development. We also show that the increase in FGF signaling that occurs when the Fgf4gain-of-function allele is activated in a wild-type limb bud causes formation of a supernumerary posterior digit (postaxial polydactyly), as well as cutaneous syndactyly between all the digits. These data underscore the importance of controlling the level of FGF gene expression for normal limb development.
Reciprocal epithelial-mesenchymal FGF signaling is required for cecal development
Authors: Zhang Xiuqin , Stappenbeck Thaddeus S. , White Andrew C. , Lavine Kory J. , Gordon Jeffrey I. , Ornitz David M.
Published: November 2005

Fibroblast growth factor (FGF) signaling mediates reciprocal mesenchymal-epithelial cell interactions in the developing mouse lung and limb. In the gastrointestinal (GI) tract, FGF10 is expressed in the cecal mesenchyme and signals to an epithelial splice form of FGF receptor (FGFR) 2 to regulate epithelial budding. Here, we identify FGF9 as a reciprocal epithelial-mesenchymal signal required for cecal morphogenesis. Fgf9null (Fgf9-/-) mouse embryos have agenesis of the embryonic cecum, lacking both mesenchymal expansion and an epithelial bud. In the cecal region of Fgf9-/- embryos, mesenchymal expression of Fgf10 and Bmp4 is notably absent, whereas the expression of epithelial markers, such as sonic hedgehog, is not affected. Using epithelial and whole explant cultures, we show that FGF9 signals to mesenchymal FGFRs and that FGF10 signals to epithelial FGFRs. Taken together,these data show that an epithelial FGF9 signal is necessary for the expansion of cecal mesenchyme and the expression of mesenchymal genes that are required for epithelial budding. Thus, these data add to our understanding of FGF-mediated reciprocal epithelial-mesenchymal signaling.
Comparison of Different Methods in Gear Curvature Analysis Using a New Approach
Authors: Puccio F Di , Gabiccini M , Guiggiani M
Published: November 2005

In the literature, some methods for curvature analysis of gears can be found, apparently very different from one another. This article presents a comparison of three approaches to stress their similarities or differences and field of application: the classic one by Litvin, its development by Chen and another one proposed by Wu and Luo and revisited by the present authors. All these methods are re-examined and expressed in a new form by means of a new approach to the theory of gearing that employs vectors and tensors. An extension of the relative motion is also considered, assuming translating axes of the gear pair and modified roll.
Vane Pump Theory for Mechanical Efficiency
Authors: Inaguma Y , Hibi A
Published: November 2005

This paper describes the theoretical analysis on the mechanical efficiency of a hydraulic-balanced vane pump and presents a design concept to decide values such as vane thickness and cam lift to improve its mechanical efficiency. In this paper, the friction torque characteristics of the balanced vane pump, especially the friction torque caused by the friction between a cam contour and vane tips are both experimentally and theoretically investigated. Although the friction force increases with vane thickness increase due to increase in the vane force, the mechanical efficiency of the vane pump does not decrease when the cam lift becomes large as the vane thickness is increased. An important parameter ∊ defined as the ratio to be obtained by dividing the cam lift by the vane thickness determines essentially the mechanical efficiency of the vane pump. The pumps with the same ∊ have the same mechanical efficiencies, even if the cam lift or the vane thickness varies. A larger value of ∊ leads the vane pump to obtain a higher mechanical efficiency although the limit of vane strength governs the upper limit for ∊. Additionally, reducing the friction coefficient of the vane tip contributes to improvement of the mechanical efficiency.
Carbon Dioxide Scrubbing from Air for Alkaline Fuel Cells Using Amine Solution in a Packed Bubble Column
Authors: Wallace J , Krumdieck S
Published: November 2005

A novel method for removal of CO2 from air is investigated. The compact, low-cost absorber is capable of scrubbing CO2 to less than 10 p.p.m. at high airflow rate, ambient temperature, and low pressure for application in alkaline fuel cells or for indoor CO2 management.
Characteristics of Torsional Vibrations of a Shaft System with Parallel Misalignment
Authors: Huang Diangui
Published: November 2005

Couplings are important parts in the movement of a shaft system. A coupling can transfer the torque from one shaft to another through deforming itself. If parallel misalignment exists, the couplings will produce an extra deformation besides the deformation produced by transferring the torque. The exciting moment with one-time rotating frequency produced by this extra deformation is analysed in this article. This moment will result in torsional vibration at one-time rotating frequency. By use of DK-II torsional vibration measurement system, an experimental study of torsional vibrational behaviour in a parallel misalignment shaft system is carried out. The experimental results support the conclusion of analysis.
On the Natural Frequencies of a Flexible Manipulator with a Tip Payload
Authors: Oguamanam D C D , Arshad M
Published: November 2005

The free vibration of a flexible manipulator that is carrying a rigid payload at the tip is examined. The centre of mass of the payload may not coincide with the point of attachment to the manipulator. The manipulator is modelled as an Euler-Bernoulli beam and it undergoes both out-of-plane and in-plane elastic flexural deformations in conjunction with torsional deformation. The explicit expression of the characteristic (or frequency) equation is presented and a parametric study is provided.
On the Steady-State Performance of Isotropically Rough Porous Hydrodynamic Journal Bearings of Finite Width with Slip-Flow Effect
Authors: Haque R , Guha S K
Published: November 2005

The objective of the present article is to theoretically investigate the static performance characteristics of rough porous hydrodynamic journal bearings of finite width with the effect of slip flow at the porous-film interface on the basis of the Beavers-Joseph criterion. In the analysis, the roughness is uniformly distributed over the bearing surfaces, with no preferred position or direction in the surface. With the concept of a stochastic process for the isotropic roughness patterns, the steady-state performance characteristics in terms of load capacity, end flowrate, and frictional parameters are obtained at different parameters of practical importance by solving simultaneously the continuity equation of flow in the porous bush and the Reynolds-type equation using the finite difference techniques. According to the results obtained, this analysis reveals that the influence of roughness on the steady-state performance of the journal bearing is physically apparent and not negligible.
Compliant Motion Control of a Three-Link Manipulator with Link Flexibility and Joint Constraints
Authors: Choi S-B
Published: November 2005

This article presents a new approach employing constraint Hamiltonian system for the compliant motion control of a three-link manipulator with link flexibility and joint constraints. Two non-linear controllers consisting of force part and position part are first derived from constraint Hamiltonian system obtained by the Lagrange and Hamiltonian methods. The linear feedback controllers that satisfy the Lyapunov stability of the total constraint Hamiltonian system are then designed. Consequently, the compliant motion control system consisting of the sum of two non-linear controllers and corresponding linear feedback controllers is formulated. The compliant motion control strategy is accomplished by steering the end effector of the manipulator onto the constraint surface with the linear controllers, and subsequently, by executing a prescribed desirable motion with the non-linear controllers. Computer simulations are undertaken in order to demonstrate the effectiveness of the proposed control methodology.
Limits on the Penetration of Coiled Tubing in Horizontal Oil Wells: Effect of the Pipe Geometry
Authors: McCourt I , Kubie J
Published: November 2005

To carry out remedial work in oil wells through the production tubing string, a method using a continuous length of steel coiled tubing is used. In horizontal wells substantial friction forces are generated which resist the motion of the tubing as it is pushed into the well. As the penetration increases, the friction forces arising from the contact of the tubing with the inner casing wall increase too, and the tubing buckles. The buckling is initially sinusoidal but eventually transforms into helical. At this point the force required to push the tubing rises dramatically, and the maximum penetration is then rapidly reached. Considerable economic benefits could be gained if the limits on the maximum penetration of coiled tubing in horizontal oil wells could be increased.

This article discusses ways of increasing the penetration of coiled tubing in horizontal oil wells by managing the geometry of the coiled tubing. It is shown that the best strategy is to keep the external diameter of the coiled tubing constant, and to make up the coiled tubing from several sections, each with uniform, but increased wall thickness. It is shown that with two sections the maximum penetration can be increased by about half, and that with three sections the maximum penetration can be increased by about two-thirds.
Oblique Impact of Thick Walled Pressurized Spheres as Used in Tennis
Authors: Haake S J , Carré M J , Kirk R , Goodwill S R
Published: November 2005

A model is presented in which the normal impact of a thick walled pressurized sphere, such as a tennis ball, is modelled as a non-linear viscoelastic spring and damper, coupled with momentum-flux forces where the shell wall deforms with high stiffness and damping. These momentum-flux forces are only present in the impact phase and do not appear during restitution. Rotation set up during an oblique impact causes the momentum-flux forces at the front and rear of the sphere to be different such that the total vertical reaction force acts in front of the centre of mass when topspin is present. The sphere was allowed to deform and this caused both the torque and the effective moment of inertia of the sphere to decrease. The result of this is that the deformed sphere gains sufficient spin during impact for reverse slip to occur when the ball reforms towards the end of impact. Tennis balls were projected at two similarly constructed surfaces with a coefficient of friction of 0.51 and 0.62. It was found that displacements and rotations from the model compared well with experimental results recorded using a high-speed video running at 7100 frames per second. The model was able to predict these results with only the coefficient of friction as the varying parameter.
Non-linear dynamics of a thin rotating disc with aerial forces
Authors: DasGupta A
Published: November 2005

This article presents a non-linear model of a thin rotating disc with aerial interaction. The disc, having an annular geometry, is modelled as a von Karman plate with perfectly clamped inner boundary and free outer boundary. The aerial force in the transverse direction is assumed to be produced by two effects: first, the resistance to transverse motion of the disc, and second, the viscous drag of the fluid. Non-linear dynamic analysis without and with external forces has been carried out. Using perturbation analysis, the frequency-amplitude relation is first determined, and the wave mode instabilities are clearly brought out. It is shown that the ratio of the coefficients of the two aerial force terms decides the stable spin speed region. Next, the response of the disc to small constant point force is studied. The linear stability of the solutions close to a critical speed is studied using solution perturbation method.
Investigation of Reciprocating Conformal Contact of Piston Skirt-to-Surface Modified Cylinder Liner in High Performance Engines
Authors: Balakrishnan S , Howell-Smith S , Rahnejat H
Published: November 2005

The article presents detailed analysis of the conforming contact between a piston and cylinder liner in a high-speed racing engine under extreme operating conditions owing to high loads and operating speeds in excess of 19 000 r/min, resulting in a high sliding velocity of 42 m/s. The analysis indicates contact forces generated in the order of 2.5 kN. The contribution due to fluid film lubrication is found to reside in iso-viscous rigid or elastic regimes of lubrication, which is insufficient to form a coherent lubricant film during some parts of the cycle, such as at top-dead-centre (TDC). The article shows that at combustion, 95 per cent of the contact can remain in boundary or mixed regimes of lubrication. Piston skirt surface modification features are used in conjunction with an electrolytically applied composite coating, Ni[SiC]p to produce advanced cylinder liners to remedy the situation. Detailed numerical analysis shows that significant improvement is achieved in the regime of lubrication condition.
Innovative design to enhance solids discharge from conical bottom ion-exchange columns. Part 1
Authors: Daas M , Retnaswamy A. V. , Srivastava R
Published: November 2005

An investigation of flow problems and solutions, associated with bulk solids discharging from conical-bottom cylindrical storage containers, is presented in this paper. The feasibility and efficiency of bulk solids discharging from these containers are directly associated with the flow pattern of the solids. The influence of a new vessel design on the flow pattern and the discharge rate of solids was examined. Glass beads of fixed particle size distribution and density were used to conduct the study. Retrofitting techniques that are commonly used to improve the flow pattern characteristics in silos were reviewed. Two techniques, utilization of inserts and hopper in hopper were investigated, and the results from the first technique are discussed. This technique is based on the usage of a double pyramid-shaped insert to manipulate the flow pattern of discharging solids. Both dry and wet tests were conducted under a wide range of low to moderate pressures. The results from both dry and wet tests showed that the pyramid insert was able to significantly change the flow pattern from the undesired funnel flow to the most desired mass flow and also increase the rate of discharge.
State-of-the-art production processes for convoluted, corrosion-resistant, high-pressure oilfield pipework
Authors: Collie G. J. , Black I
Published: November 2005

Currently, there are two widely used methods for manufacturing corrosion-resistant, high-pressure pipework for oilfield applications: fabrication of the pipework from several, separate overlaid components joined by welding, or by combining fabrication and induction bending. The former is expensive and time consuming. The latter is less expensive but there are restrictions on the bend radii that can be achieved.

This paper considers a range of possible alternatives in the production of complex, corrosionresistant, high-pressure piping systems for oilfield equipment. Some of the options (hot-rolled and seam-welded pipe, explosion-bonded and seam-welded pipe, and bi-metallic extrusions) result in an end product that is broadly comparable with that produced by fabrication. Others (epoxy coating, shape memory polymer, preformed plastic liner, cured-in-place plastic liner, and liquid coating) do not provide a metallic coating but are used in similar applications in different industries. Finally, there are technologies (such as plating, hot isostatic pressing, ceramic lining, and vapour deposition) that are proven processes but have no current application that may be considered directly relevant to high-pressure piping systems. One new concept under development by the authors is introduced - the use of a thin-walled liner manufactured from a corrosion resistant alloy, and expanded into a prebent carbon steel pipe.
A mathematical model for airflow and heat transfer through fibrous webs
Authors: Hossain M , Acar M , Malalasekera W
Published: November 2005

A mathematical model based on computational fluid dynamics has been developed to investigate the airflow and heat transfer through fibrous webs. The model is based on the porous media concept and involves solving equations for continuity, momentum, and energy. A thermal energy equation is developed, which incorporates the heat of fusion of fibres in the fibrous web. Local flow information such as air velocity, temperature, and melt fraction of fibres is obtained from the simulations. An important outcome of the simulation is the prediction of time required to melt fibres in the web under different working conditions. This information can be used potentially in the design of through-air bonding process for nonwovens manufacturer.
Modelling and simulation of a power plant lignite bunker filling process using hybrid interpreted Petri nets
Authors: Antoniadis I. A.
Published: November 2005

The complexity of the continuous type processes involved in the power industry, typically involving a large number of parameters and equations, combined with the discrete type of the controls of the installation, necessitate the introduction of hybrid modelling procedures. Although hybrid Petri nets (HPN) have been introduced for this purpose, they still present limitations in modelling such complex situations. For this reason, they are properly combined with another type of Petri nets - the interpreted Petri nets - in order to take into account the external events also, resulting either from the environment or from the actions of the control system. The resulting combined theoretical analysis framework leads to the concept of hybrid interpreted Petri nets. This framework is then applied to model the lignite bunker filling process of an actual power plant, indicating an efficient and flexible behaviour, during both the normal, and the fault handling operation of the system.
Detection of incipient cavitation and determination of the best efficiency point for centrifugal pumps using acoustic emission
Authors: Alfayez L , Mba D
Published: November 2005

Pumps play a significant role in industrial plants and need continuous monitoring to minimize loss of production. To date, published information on the application of acoustic emission (AE) to incipient pump cavitation has been contradictory. This article re-assesses the application of AE for detecting incipient cavitation. In addition, this paper presents results from an on-going programme to ascertain the applicability of the AE technique for determining the best efficiency point (BEP) of an operating system. Three different sized pumps (60 kW, 127 kW, and 2.2 MW) formed the basis of this investigation, which included NPSH (net positive suction head) and performance tests. Results obtained demonstrate the successful use of the AE technique for detecting incipient cavitation and highlight the enormous potential of the technique in determining the BEP of a pump or system.
Numerical simulations and experimental measurements of the flow in a multi-tube heat exchanger
Authors: Hughes J. P. , Shaw G. H. , Tucker G. S. , James P. W. , Jones T. E. R.
Published: November 2005

This paper describes numerical simulations and experimental measurements of isothermal and non-isothermal flow of non-Newtonian fluids in the shell side of a multi-tube tubular heat exchanger. Some results for the turbulent isothermal flow of water are also presented. A single pass of a commercially available Tetra Spiraflo 7x16MT multi-tube heat exchanger has been instrumented to provide pressure drop and temperature data. Numerical predictions obtained with commercial software are generally in good agreement with measurements. The simulations are then used to determine more detailed features of the shell-side flow in this type of multi-tube heat exchanger. The work forms part of a project investigating the use of multi-tube heat exchangers in heat recovery mode for medium viscosity food products.