bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of fabric structure on sodium hydroxide release from woven lyocell
Authors: Široky Ján , Blackburn Richard S , Bechtold Thomas
Published: July 2011

The sodium hydroxide release (alkali wash-off) from lyocell fabrics with different weave constructions (plain, twill, sateen) was studied by conductivity measurements in the wash bath. An alkali transport coefficient (K) was established to quantify alkali release, which represents the liquid-side mass transfer of alkali release after a pad-batch process into the wash bath.

Three regions of NaOH-release behaviour were observed and two competitive phenomena related to swelling, increase of the substrate surface, and the substrate compactness, have been recognized. Firstly (up to 2.25 mol dm-3), the influence of fabric-alkali interactions and non-uniform access of NaOH determines alkali release, and also the absolute K value is mainly determined by the bulk densities (plain 0.4998, twill 0.4622 and sateen 0.4096 g cm-3) and porosities (plain 0.671, twill 0.696 and sateen 0.731) and thus, it increases continuously. The maximum swelling of cellulose fibers occurs between 2.25—3.00 mol dm-3 NaOH; here, maximum K is observed as well as dependency on fabric construction is still determining factor. Above 3.75 mol dm-3 NaOH, the treated substrates are highly swollen sheets and the K does not show dependency on fabric constructions, thus, the fabric construction is not relevant at this range anymore for the alkali-diffusion.

Because materials consisting of the same type of fiber and with similar mass per area are currently considered to behave identically, the findings herein which contrast with the existing theory are of particular relevance in optimization of technical processing of regenerated cellulosic fabrics during alkalization.
Classrooms as Racialized Spaces
Authors: Nunn Lisa M.
Published: July 2011

This article interrogates the construction of ethnoracial categories in everyday classroom life and how ethnoracial classroom dynamics contribute to larger patterns of inequality in achievement and unequal college futures for minorities. The study compares one urban and two suburban schools. Drawing on observation data from six classes and 57 in-depth student interviews, I find that ethnoracial categories are continually reconstructed through teachers’ pedagogical styles and students’ interactions. In addition, metainstitutional structures such as curriculum tracks and nonacademic dynamics foster ethnoracial tensions between classmates. While the urban school successfully alleviates ethnoracial stereotypes, the suburban schools exacerbate ethnoracial divisions among students.
Somebody’s Gotta Fight for Them
Authors: Watson Sunnie Lee
Published: July 2011

This year-long ethnographic study explores one alternative school’s journey of creating a positive and collaborative learning community while negotiating through the disadvantages and marginalization within a school district and society at large. This study examined various aspects of school culture, including learning processes, discourses, relationships, and challenges the students and teachers face in schools. Participants discussed the importance of a flexible learning environment, strong relationships between students and teachers, while displaying a strong resistance toward authority. How schools must change to meet all students’ needs still remains a vital question.
Exposing Color Blindness/Grounding Color Consciousness
Authors: Ullucci Kerri , Battey Dan
Published: July 2011

As teacher educators we have been struck by the consistency, urgency, and frequency in which students employ color-blind perspectives. This orientation has negative consequences in K-12 settings. In this manuscript, we lay out the multiple meanings of color blindness, drawing from legal, educational, and social science traditions, and offer arguments for color consciousness in education. In addition, we use this theoretical perspective to investigate interventions for countering color blindness in teacher education. Using a framework steeped in the tenets of color consciousness, we draw from scholars as well as our own work to provide interventions designed to challenge color-blind orientations in teachers.
Global Village Versus Culture Shock
Authors: Dunn Alyssa Hadley
Published: July 2011

Though international teachers have been present in U.S. schools for decades, their recruitment for urban schools as a response to the supposed teacher shortage is a relatively new phenomenon with little research to support it. This study examines international teachers’ recruitment and preparation for urban environments. Informed by classroom observations and in-depth interviews with teachers, administrators, and recruitment agency personnel, this collective case study finds that there are distinct benefits and challenges of recruitment and that recruitment procedures and lack of preparation for U.S. schools add to teachers’ challenges. Recommendations are included for future research, teacher education, and policy.
Rethinking a Megalopolis
Authors: Perlman Bruce J. , Guadarrama Juan de Dios Pineda
Published: July 2011

This essay looks at the governance arrangements and challenges of “Mexico City,” one of the largest and most complex capital cities in the world and a true “Megalopolis.” The essay begins by presenting the background of the governmental structure of the Mexico City area which includes both old districts and a new metropolitan zone. It then goes on to present some of the challenges facing this structure, including basic service delivery and infrastructure provision for the geographically large, diverse, and sometimes politically disparate area. The complicated governance and administrative structure which must meet these challenges is then explained. Finally, the essay concludes with some proposals for rethinking this governance structure to make it more efficient and representative.
Spousal Bereavement as a Triggering Mechanism for a Loss of Residential Independence Among Canadian Seniors
Authors: Strohschein Lisa
Published: July 2011

Although it is well recognized that unmarried seniors are more likely to experience instability in their living arrangements than their married counterparts, few studies have tested whether spousal bereavement in and of itself operates as a triggering mechanism for a subsequent loss of residential independence. The purpose of this study was to investigate whether Canadian seniors are at greatest risk for institutionalization and coresidence with others in the period immediately following spousal bereavement and whether this risk declines as acute responses to the crisis of bereavement become tempered with time. Data come from six waves of the Canadian National Population Health Survey (1994-2004), with the sample restricted to married or cohabiting adults who, at initial interview, were 65 years of age or older and living in a couple-only household ( n = 1,082). Results from a competing risks analysis for time to first event, where first event was either moving into an institution or sharing a residence with others, confirm the time-dependent consequences of spousal bereavement. Relative to seniors whose spouse was still living 10 years later, respondents who experienced the death of a spouse or partner between 1994 and 2004 were at significantly greater risk for both institutionalization and coresidence in the period immediately following bereavement, with risk attenuating over time.
Differences in craving for cannabis between schizophrenia patients using risperidone, olanzapine or clozapine
Authors: Machielsen Marise , Beduin Albertine Scheltema , Dekker Nienke , Kahn René S , Linszen Don H , van Os Jim , Wiersma Durk , Bruggeman Richard , Cahn Wiepke , de Haan Lieuwe , Krabbendam Lydia , Myin-Germeys Inez
Published: July 2011

Substance abuse and psychotic disorders have a high rate of comorbidity. Both disorders are associated with changes in the dopaminergic transmission in the mesocorticolimbic pathways of the brain. Since antipsychotic medications interact with the dopamine receptors in these pathways, these medications could affect craving for substances. In the current study, the effect of clozapine ( n = 27, mean dosage 350 mg), risperidone ( n = 54, mean dosage 3.46 mg) and olanzapine ( n = 60, mean dosage 13.78 mg) on subjective craving for cannabis was compared in 123 patients with cannabis dependence and psychotic disorder. Patients treated with risperidone reported significantly more craving compared with patients treated with clozapine ( Z = −3.19, p = .001) or olanzapine ( Z = −2.24, p = .025). No significant differences in craving between clozapine and olanzapine were found. These results are in concordance with findings in the literature on this subject and could be explained by differences in three dopamine mediated mechanisms of these compounds: 1) occupancy rate of dopamine D2 receptors, 2) dissociation rate of dopamine D2 receptors, 3) D1/D2 occupancy ratio. Risperidone and clozapine show a maximal difference in D2 receptor occupancy rate, dissociation rate and D1/D2 ratio. Olanzapine is intermediate between risperidone and clozapine in these characteristics.
The endocannabinoid system in anxiety, fear memory and habituation
Authors: Ruehle S , Rey A Aparisi , Remmers F , Lutz B
Published: July 2011

Evidence for the involvement of the endocannabinoid system (ECS) in anxiety and fear has been accumulated, providing leads for novel therapeutic approaches. In anxiety, a bidirectional influence of the ECS has been reported, whereby anxiolytic and anxiogenic responses have been obtained after both increases and decreases of the endocannabinoid tone. The recently developed genetic tools have revealed different but complementary roles for the cannabinoid type 1 (CB1) receptor on GABAergic and glutamatergic neuronal populations. This dual functionality, together with the plasticity of CB1 receptor expression, particularly on GABAergic neurons, as induced by stressful and rewarding experiences, gives the ECS a unique regulatory capacity for maintaining emotional homeostasis. However, the promiscuity of the endogenous ligands of the CB1 receptor complicates the interpretation of experimental data concerning ECS and anxiety. In fear memory paradigms, the ECS is mostly involved in the two opposing processes of reconsolidation and extinction of the fear memory. Whereas ECS activation deteriorates reconsolidation, proper extinction depends on intact CB1 receptor signalling. Thus, both for anxiety and fear memory processing, endocannabinoid signalling may ensure an appropriate reaction to stressful events. Therefore, the ECS can be considered as a regulatory buffer system for emotional responses.
Virus Distribution and Role of Thymic Macrophages During Experimental Infection With Noncytopathogenic Bovine Viral Diarrhea Virus Type 1
Authors: Raya A. I. , Gomez-Villamandos J. C. , Sánchez-Cordón P. J. , Bautista M. J.
Published: July 2011

Thymic depletion, presence of viral antigen, and changes in distribution and cytokine production of thymic macrophages were investigated in calves experimentally infected with a noncytopathogenic bovine viral diarrhea virus type (BVDV) 1 strain. Ten clinically healthy colostrum-deprived calves were used. Eight calves were inoculated with the virus and two were used as uninfected controls. Calves were sedated and euthanized in batches between 3 and 14 days postinoculation. At necropsy, thymus samples were collected for structural, immunohistochemical, and ultrastructural study and TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling). From 6 days postinoculation, the thymic cortex was multifocally depleted with increased frequency of pyknosis and karyorrhexis, suggestive of apoptosis and confirmed by the TUNEL technique. Although the onset of lymphoid depletion was coincident with the detection of viral antigen by immunohistochemistry, the number of infected lymphocytes was very low through the experiment. There was an increase in number of macrophages in cortex and medulla, accompanied by ultrastructural changes indicative of phagocyte activation, and a decrease in cells expressing tumor necrosis factor-alpha (TNF-α) and IL-1α. These results suggest that the increase in number of these cells could be related to phagocytosis of cell debris and apoptotic lymphocytes. Furthermore, the results imply that, in contrast to the situation with classical swine fever virus, the lymphocyte apoptosis resulting from bovine viral diarrhea virus infection is not mediated by TNF-α or interleukin-1 alpha (IL-1α) production by virus-infected macrophages. This is the first study that describes this decrease in the number of thymic cells expressing TNF-α and IL-1α in cattle experimentally infected with bovine viral diarrhea virus type 1.
Coastal geomorphology
Authors: French J.R. , Burningham H.
Published: July 2011

This progress report presents a selective review of developments in coastal geomorphological research, and their relation to trends in geomorphology as a whole. The continuing advance of environmental monitoring technology is evidenced by the number of papers showcasing new instruments and the data sets that they can generate, especially in relation to the analysis of coastal change. As ever, some areas of research rise in prominence while others fade away, a pattern that probably owes more to the current vogue for journal special issues than any real focusing or coordination of research effort. Rocky coasts and fetch-limited shorelines feature strongly in the literature for 2009 and 2010, while a more diverse set of studies attack the problem of disaggregating temporal variability in sediment fluxes and morphology into specific process controls. Quantitative sediment budgets continue to underpin analyses of coastal change, especially those that attempt to relate erosion with human activities. Of particular interest are studies that attempt to achieve more rigorous closure of budgets through explicit treatment of onshore-offshore fluxes, and analyses that address the interplay between anthropogenic and natural forcing. More generally, there are signs that a new age of discovery is being facilitated by the worldwide coverage of aerial and satellite imagery provided by portals such as Google Earth. This has the potential to enrich the geographical context of geomorphological research, and to contribute also to classificatory and empirical studies.
The Influence of Musculoskeletal Injury on Cognition
Authors: Hutchison Michael , Comper Paul , Mainwaring Lynda , Richards Doug
Published: July 2011

Background: Safe return-to-play decisions after concussion can be challenging for sports medicine specialists. Neuropsychological testing is recommended to objectively measure concussion-related cognitive impairments.

Purpose: The objective of this study was to measure cognitive functioning among 3 specific athletic groups: (1) athletes with no injuries (n = 36), (2) athletes with musculoskeletal injuries (n = 18), and (3) athletes with concussion (n = 18).

Study Design: Case-control study; Level of evidence, 3.

Methods: Seventy-two intercollegiate athletes completed preseason baseline cognitive testing and follow-up assessment using the Automated Neuropsychological Assessment Metrics (ANAM) test battery. Injured athletes were tested within 72 hours of injury. A 1-way analysis of covariance adjusted for baseline scores was performed to determine if differences existed in cognitive test scores among the 3 groups.

Results: A group of athletes with concussion performed significantly worse than a group of athletes with no injuries on the following subtests of the ANAM at follow-up: Code Substitution Learning, Match to Sample, and Simple Reaction. Athletes with musculoskeletal injuries performed significantly worse than those with no injury on the Match to Sample subtest. No significant differences between athletes with concussion and athletes with musculoskeletal injuries were found on all ANAM subtests.

Conclusion: Concussion produces cognitive impairment in the acute recovery period. Interestingly, athletes with musculoskeletal injuries also display a degree of cognitive impairment as measured by computerized tests.

Clinical Relevance: Although these findings support previous research that neuropsychological tests can effectively measure concussion-related cognitive impairment, this study provides evidence that athletic injury, in general, also may produce a degree of cognitive disruption. Therefore, a narrow interpretation of scores of neuropsychological tests in a sports concussion context should be avoided.
Comparison of Different Fixation Methods of the Suture-Button Implant for Tibiofibular Syndesmosis Injuries
Authors: Teramoto Atsushi , Suzuki Daisuke , Kamiya Tomoaki , Chikenji Takako , Watanabe Kota , Yamashita Toshihiko
Published: July 2011

Background: Suture-button fixation for tibiofibular syndesmosis injuries is a relatively new surgical technique thought to provide semirigid dynamic stabilization. However, adequate information is still not available and there are controversies as to whether it provides enough fixation for syndesmosis injuries.

Hypothesis: Optimally directed suture-button fixation brings physiologic dynamic stabilization of the ankle syndesmosis.

Study Design: Controlled laboratory study.

Methods: Stabilization of the ankle syndesmosis fixed by a suture-button construct was examined using 6 normal fresh-frozen cadaver legs. After initial tests of intact and injured models, suture-button fixation and screw surgical techniques were performed sequentially for each specimen, with single suture-button fixation, double suture-button fixation, anatomic suture-button fixation, and metal screw. Anterior and medial traction forces, as well as external rotation force, were applied to the tibia; the diastasis of the syndesmosis and the rotational angle of the fibula related to the tibia were measured using a magnetic tracking system.

Results: Each traction and rotation force significantly increased the diastasis and fibular rotational angles in the created injury models. With single fixation, the diastases increased significantly compared with the intact model with an anterior traction force ( P < .001), a medial traction force ( P = .005), and an external rotation force ( P = .015). The fibular rotational angles increased significantly with a medial traction force ( P = .005) and an external rotation force ( P < .001). With double fixation, the diastases increased significantly with a medial traction force ( P = .004) and an external rotation force ( P = .012). The fibular rotational angles increased significantly with a medial traction force ( P = .035) and an external rotation force ( P = .002). With anatomic fixation, there were no significant differences compared with the intact model. With the metal screw, the diastases decreased significantly with an external rotation force ( P = .037).

Conclusion: Neither single nor double fixation for syndesmosis injuries provided multidirectionally stabilizing syndesmosis. Anatomic fixation directed from the posterior cortex of the fibula to the anterolateral edge of the tibia allowed dynamic stabilization of intact cadaver specimens. The metal screw provided very rigid fixation.

Clinical Relevance: Optimal direction of the suture button can provide adequate stabilization of the ankle and could benefit athletes with syndesmosis injuries.
Evaluation of differential representative values between Chinese hamster cells and human lymphocytes in mitomycin C-induced cytogenetic assays and caspase-3 activity
Authors: Liao Pei-Hu , Lin Ruey-Hseng , Yang Ming-Ling , Li Yi-Ching , Kuan Yu-Hsiang
Published: July 2011

Chinese hamster ovary (CHO) cells, its lung fibroblasts (V79), and human lymphocytes are routinely used in in vitro cytogenetic assays, which include micronuclei (MN), sister chromatid exchange (SCE), and chromosome aberration (CA) assays. Mitomycin C (MMC), a DNA cross-link alkylating agent, is both an anticancer medicine and a carcinogen. To study the differential representative values of cell types in MMC-treated cytogenetic assays and its upstream factor, cysteine aspartic acid-specific protease (caspase)-3. Among the chosen cell types, lymphocytes expressed the highest sensitivity in all three MMC-induced assays, whereas CHO and V79 showed varied sensitivity in different assays. In MN assay, the sensitivity of CHO is higher than or equal to V79; in SCE assay, the sensitivity of CHO is the same as V79; and in CA assay, the sensitivity of CHO is higher than V79. In-depth analysis of CA revealed that in chromatid breaks and dicentrics formation, lymphocyte was the most sensitive of all and CHO was more sensitive than V79; and in acentrics and interchanges formation, lymphocyte was much more sensitive than the others. Furthermore, we found caspase-3 activity plays an important role in MMC-induced cytogenetic assays, with MMC-induced caspase-3 activity resulting in more sensitivity in lymphocytes than in CHO and V79. Based on these findings, lymphocyte will make a suitable predictive or representative control reference in cytogenetic assays and caspase-3 activity with its high specificity, positive predictive value, and sensitivity.
Gait Assessment in Children With Duchenne Muscular Dystrophy During Long-Distance Walking
Authors: Ganea Raluca , Jeannet Pierre-Yves , Paraschiv-Ionescu Anisoara , Goemans Nathalie M. , Piot Christine , Van den Hauwe Marleen , Aminian Kamiar
Published: July 2011

The aim of this study was to investigate the alteration of the gait pattern in 25 children with Duchenne muscular dystrophy, using body-worn inertial sensors during a long walking distance. Normalized spatiotemporal gait parameters and their variability were extracted from the angular velocity of the shanks; the smoothness of the trunk movement was assessed based on the spectral entropy of the acceleration norm. As compared to healthy children, patients with Duchenne muscular dystrophy showed significantly lower stride velocity and a less smooth trunk movement. When the group of patients was divided into mild and moderate based on the Motor Function Measure, the authors noticed significantly higher values both for cadence and stride velocity, as well as improved trunk smoothness in the mild versus moderate group. The potential of such parameters to distinguish between different disease states opens new perspectives for the objective assessment of efficacy of the new therapies associated with Duchenne muscular dystrophy.
A National Survey on Hospital Formulary Management Processes
Authors: Anagnostis Ellena , Wordell Cindy , Guharoy Roy , Beckett Robert , Price Venessa
Published: July 2011

Purpose: In light of formulary management guidelines from the American Society of Health-System Pharmacists (ASHP), and discussion of pharmacies' noncompliance with recent Joint Commission accreditation requirements, the University HealthSystem Consortium conducted a formulary management survey to determine member institutions' standard of practice. Methods: An electronic survey was distributed to 227 institutions. Questions pertained to formulary structure, policies and procedures to manage formulary processes, tracking nonformulary medication use, pharmacoeconomic assessment, and Food and Drug Administration (FDA)-approved versus off-label medication use. Results: Fifty-two institutions across the United States provided responses. Most institutions maintain written policies for how medications are requested (94%) and reviewed (88%) for formulary addition; 92% of institutions have a nonformulary medication process. Nonformulary medication use is tracked at 88% of institutions, and 85% of institutions conduct pharmacoeconomic analyses. Regarding The Joint Commission’s requirement to approve drugs for specific indications, 40% of institutions approve drugs for all FDA-approved indications; 35% of institutions have not formally addressed this requirement. Approximately 31% of the institutions have a policy for approving a medication for an off-label indication. Conclusion: Portions of the ASHP guidelines have been implemented by most institutions, while 35% of institutions have yet to address The Joint Commission’s clarification to approve drugs for specific indications.
Concepts for and analysis of a high accuracy and high capacity (HAHC) aerospace robot
Authors: Muelaner J E , Wang Z , Maropoulos P G
Published: July 2011

Case study work carried out within the aerospace sector has highlighted the requirement for highly accurate and high capacity robots in aerospace assembly; literature supports this observation. This paper presents the generic capabilities of such a system. These include the ability to rapidly locate itself within a large measurement volume using supplementary laser metrology systems, to carry out detailed inspection beyond the line of sight, and to accurately locate parts, drill holes and fettle interfaces. Concepts are presented for a standardized robot which would provide a flexible automation system able to carry out a full range of operations required in the assembly of large aerospace structures. Two possible solutions are detailed, one based on error mapping and one based on the physical isolation of encoders from structural loading using an exoskeleton approach.
Flexible optimization decision for product design agility with embedded real options
Authors: Dong M , Shao X , Xiong S
Published: July 2011

One of the evolving trends in today’s marketplace is that consumers are demanding ever more innovative goods that are tailored to their specific needs. This requires that companies need to create products that either can be rapidly evolved or can be customized to meet specified personal requirements. On the other hand, the scale of economy brought by mass production is also desired. An approach called mass customization (MC) has been proposed to solve these two conflicting criteria. An important way to achieve MC is through modular product design and shared product platform development. In this paper, a flexible modular product design optimization decision model is proposed. To address the different attributes of customers’ demands, the optimization model is decomposed into profit, cost, value, and demand sub-models. In order to be adaptive to the changes in customer requirements two levels of flexibility are endowed within the model. The first level of flexibility consists in embedded options. Small adjustments to a product can be made using these options. When the customer demands a radical change to a product or there are several concurrent small changes that need to be made then the product design model needs an optimization decision route to guide the reconfiguration. This is the second level of flexibility that indicates an evolution within the scope of the overall structure of the product design. The flexible decision-making procedures are iterative in order to make the product design to evolve from one generation to another. A notebook computer example is used to illustrate the proposed concepts. Numerical experiments on mobile phone designs are used to verify the effectiveness of the proposed methods.
Opposing effects of recirculated gases during cranking on cold start of diesel engines
Authors: Rofail R N , Henein N A , Bryzik W
Published: July 2011

The effect of recirculating engine-out gases into the intake manifold on the cold start of direct-injection diesel engines is investigated. Two types of recirculation are examined. The first is low-pressure recirculation of engine-out gases into the intake manifold where their rate is controlled by a gas recirculation (GR) valve installed between the exhaust and intake manifold. The second is high-pressure recirculation by restricting the flow of the engine-out gases using a butterfly (BF) valve, installed in the exhaust system after the turbocharger to increase the back pressure and the rate of recirculated gases. Since there is no combustion during cranking, these gases contain evaporated hydrocarbons and partial oxidation products, mostly formaldehyde (HCHO). Experimental investigations on a four-cylinder direct-injection diesel engine indicated that high rates of cranking gas recirculation (CGR) increase the ignition delay and lengthen the cranking period. Since higher concentrations of hydrocarbons (HC) are expected to enhance the autoignition process, it is suspected that the recirculated HCHO would have an opposite effect. These opposing effects are investigated using the ChemKin diesel cycle simulation model. The model results demonstrated the effect of HCHO on slowing the autoignition and combustion reactions.
Hunting stability and derailment analysis of a car model of a railway vehicle system
Authors: Cheng Y-C , Hsu C-T
Published: July 2011

Using a heuristic linear creep model, this article derives the governing differential equations of motion for a vehicle travelling on curved tracks. The vehicle is modelled by a 27-degrees-of-freedom (27-DOF) car system, with lateral and vertical displacement, roll and yaw angle of each wheelset and the bogie frames, as well as lateral displacement, and roll and yaw angle of the car body taken into consideration. To analyse the respective effects of major system parameters on vehicle dynamics, the 27-DOF system is reduced to a 14-DOF system by excluding designated subsets of the system parameters. The effects of suspension parameters of a vehicle on the critical hunting speeds were evaluated by the 14- and 27-DOF systems. The results obtained in this study, show that the critical hunting speeds derived using the 14-DOF system are generally higher than those obtained using the 27-DOF system. Additionally, the critical hunting speeds derived using the heuristic non-linear creep model are lower than those achieved using the linear creep model. The effects on derailment quotients of vehicle speeds are evaluated using both linear and non-linear creep models with various suspension parameters. Finally, the effects of vehicle speed on the derailment quotient for sharp curves and low vehicle speed are investigated and compared with both linear and non-linear creep models.
Evaluation of non-equilibrium by the Crocco theorem
Authors: Zuppardi G , Morsa L
Published: July 2011

The quantification of non-equilibrium is important both in computational fluid dynamics to identify regions where the flow field can be considered isentropic or not and in direct simulation Monte Carlo (DSMC) method to identify regions where the number of molecular collisions should be more or less high. As it is well known, thermodynamic non-equilibrium and anisotropy are two aspects of non-equilibrium. The parameters quantifying thermodynamic non-equilibrium rely on the difference of the local values of the translational temperature with respect to the rotational and vibrational temperatures. The parameters, quantifying anisotropy, rely on the difference of the local values of the three spatial components of the translational temperature. A measure of ‘global’ non-equilibrium relying on just one parameter that includes thermodynamic non-equilibrium and anisotropy at the same time could be preferable from an operative point of view. Such a single parameter has been already introduced; this is the entropy generation rate that identifies the non-equilibrium regions, whereas a positive entropy generation exists. In this study, a ‘new’ parameter is proposed. The method obtaining this new parameter relies on the assumption that a theoretical equation, based on the hypotheses of equilibrium, is not verified in non-equilibrium. The equation of the Crocco theorem showed to be proper for this purpose; the new parameter is defined as the difference of the terms forming the equation. This parameter verified to be more effective than the parameters based on the temperature differences because it was able to identify the non-equilibrium regions in a more precise and evident way. Computing tests considered a slab normal to the free stream velocity in the whole transitional regime. For this reason, the runs have been carried out by a DSMC code.
Repeated measurement of mechanical properties in viable osteochondral explants following a single blunt impact injury
Authors: Ramakrishnan P S , Pedersen D R , Stroud N J , McCabe D J , Martin J A
Published: July 2011

The objective of this work was to develop a method for repeated same-site measurement of mechanical properties suitable for the detection of degenerative changes in a biologically active explant model after a single blunt impact injury. Focal blunt impact injuries to articular surfaces lead to local cartilage degeneration and loss of mechanical properties. We employed a repeated measurement methodology to determine variations in mechanical same-site properties before and after injury in living cartilage, with the hypothesis that normalization with initial mechanical properties may provide a clearer evaluation of impact effects and improve our understanding of the biologic responses to impact injury. Bovine osteochondral explants were cultured for up to 14 days after impact injury. Indentation tests were performed before and after impact injury to assess relative changes in mechanical properties. Creep strain increased significantly in impacted explants after 7 days and in both impacted and control explants after 14 days. Further analysis at 14 days revealed decreases in stretch factor β, creep time constant and local compressive modulus. A repeated measures methodology reliably detected changes in the mechanical behaviour of viable osteochondral explants after a single impact injury.
Functional and structural effects of percutaneous edge-to-edge double-orifice repair under cardiac cycle in comparison with suture repair
Authors: Avanzini A , Donzella G , Libretti L
Published: July 2011

Percutaneous procedures for double-orifice mitral valve repair using the MitraClip® device (clip) have been recently introduced as new treatment options as alternatives to medical management and open-heart surgery, especially for patients with high estimated operative risk. Similarly to the open-heart surgical technique, where suturing is used, the clip creates a double-orifice configuration that not only improves the closing function of the valve, but also significantly modifies its behaviour, particularly in the diastolic phase. While several clinical trials have been conducted, and are ongoing, in order to assess the safety and effectiveness of this technique, a deeper knowledge of the structural and functional effects on the valve, and of the cyclic loads transmitted to the clip itself, would allow a comparison with other repair techniques, and could serve as a foundation for possible further optimization of the clip design. The effects of the MitraClip® device developed by Evalve Inc. were studied by means of a finite element model of the mitral valve, specifically developed to study the structural effects of the original, suture-based, edge-to-edge technique. A second model was developed in order to simulate the effects of a suture with similar extension from the leaflet edge in a direction to the annulus, in order to compare the two repair techniques. The mitral valve area and transvalvular pressure gradient predicted by the models for the clip and the suture are quite similar. Similar leaflet cyclic stresses, both in value and in location, were noted for the two mechanisms of linking the leaflets, while minor differences were found in the load transmitted to the suture and the clip, with slightly higher values for the clip. The model satisfactorily allowed functional parameters (valve area and transvalvular pressure gradient) and structural parameters (load, leaflet stress) to be determined. Overall, the structural effects of the clip and the suture are quite similar under the cyclic loading conditions imposed by the cardiac cycle.
A comprehensive study on performance, emission, and combustion characteristics of a dual-fuel engine fuelled with orange oil and Jatropha oil
Authors: Senthilkumar M , Ramesh A , Nagalingam B , Tazerout M
Published: July 2011

Performance of a single-cylinder, water-cooled, direct-injection diesel engine on dual-fuel operation with Jatropha oil (JO) as pilot fuel and orange oil as primary fuel was evaluated. Constant load test at different power outputs was conducted at the rated speed of 1500 r/min with varying orange oil quantities. The loads were fixed as 20 per cent, 40 per cent, 60 per cent, 80 per cent, and 100 per cent.

In dual-fuel operation with orange oil induction, the thermal efficiency of JO was increased mainly at high power outputs. Maximum thermal efficiency with JO was found as 29 per cent at 31 per cent of orange oil induction at 100 per cent load. Smoke was reduced significantly with all orange oil induction rates at all power outputs in dual-fuel operation with JO. It was reduced from 4.4 to 3.3 BSU (Bosch Smoke Units) with JO at the maximum efficiency point at 100 per cent load. HC emissions were increased further at all power outputs in the dual-fuel mode with all rates of orange oil induction. Dual-fuel operation increased the ignition delay of JO. However, peak pressure and energy release rates were improved in the dual-fuel operation with orange oil induction. In general, dual-fuel operation with orange oil as inducted fuel with JO as pilot fuel showed inferior performance and emissions at part loads.

It is concluded that the JO as pilots fuel and orange oil as the inducted fuel could be used in diesel engines with reduced smoke levels and improved thermal efficiencies with no major detoriation in performance.
Effect of operating condition on the particulate matter emission factor for a domestic biomass boiler
Authors: Smith W J , Morrin S , Timoney D J
Published: July 2011

The effect of operating condition on the particulate matter emission factor for a domestic biomass boiler has been examined, with a view to improving emission inventories compiled under the Convention on Long-Range Transboundary Air Pollution (CLRTAP). It was found that the emission factor depended strongly on the boiler load, and that there were significant differences between the value used in current emission inventories and actual values found in a combustion installation from a typical domestic dwelling.
The effect of cross-winds on an indirect dry cooling tower with or without windbreaks
Authors: Reshadatjoo H , Pormahmod N , Moltagh S Y
Published: July 2011

In this article, the flow pattern of an indirect dry cooling tower (Heller) under cross-wind conditions has been numerically investigated and the obtained results have been compared with the available experimental results. Furthermore, the phenomena responsible for the reduction of air intake flowrate (AIFR) under cross-wind conditions have been identified. The influences of wind speed increase on the flow pattern inside the tower and on the AIFR have been studied quantitatively and qualitatively. Finally, by adding radial windbreak walls to the base section of tower, their effect on the flow pattern and on tower performance from the AIFR perspective has been investigated.
Choice of a turbulence model for pump intakes
Authors: Škerlavaj A , Škerget L , Ravnik J , Lipej A
Published: July 2011

This article is focused on the choice of a suitable turbulence model for simulations of an industrial pump's intake, from the perspective of accuracy and, partially, also the CPU time. Twelve steady-state and transient simulations were made on a fine computational mesh, using turbulence models such as: the shear stress transport (SST), the scale-adaptive simulation (SAS), the Reynolds stress model, the explicit algebraic Reynolds-stress model, the detached eddy simulation and the large eddy simulation (LES). The curvature-correction (CC) option was assessed for the SST and SAS turbulence models. The results were compared with the LES and with published experimental results. Although all the models could predict the main floor vortex, there were still some substantial differences. It can be able to conclude that it is better to use either the SST-CC turbulence model, due to its low-computational resources and far better results than the SST model, or the SAS-CC turbulence model, since its predictions are quite similar to the LES results. In the final step, good agreement with experimental results was shown for a longer simulation with the SAS-CC turbulence model.
A low-Reynolds-number, high-angle-of-attack investigation of wind turbine aerofoils
Authors: Worasinchai S , Ingram G , Dominy R
Published: July 2011

This article describes an experimental, aerodynamic investigation of four aerofoils intended for small wind turbine applications. The aerofoils of these small machines (both horizontal and vertical axes) normally experience conditions that are quite different from large-scale machines due to smaller chord length and lower wind speed, resulting in significantly lower Reynolds numbers. They also operate with an unusually wide range of incidence angles (0° to 90° for horizontal axis and 0° to 360° for vertical axis). Four appropriate aerofoils were chosen for testing at three Reynolds numbers (65 000, 90 000, and 150 000) through 360° incidence to cover almost all possible conditions that might be encountered by both types of turbines. The investigations were conducted in terms of lift, drag, and surface static pressure coefficients. The experimental results show that both geometry and Reynolds number had significant effects on aerodynamic lift, not only when unstalled but particularly in the post-stall region from 20° to 50° incidence. These effects were also seen at other incidences but to a lesser extent. By contrast, the drag characteristics were similar for all blade geometries. Static pressure measurement revealed that, at these low Reynolds numbers, separation bubbles always form near the leading edge of the suction surface at moderate incident angles and increase in size with decreasing Reynolds number. Comparisons of force and static pressure measurements showed that the aerofoil stalling behaviour is closely related to the presence of a separation bubble at the leading edge of the suction surface. Discrepancies between the experiments and predictions using the AERODAS model confirm the continued need for accurate wind tunnel testing.
Analysis and optimization of a transcritical power cycle with regenerator using artificial neural networks and genetic algorithms
Authors: Rashidi M M , Bég O Anwar , Parsa A Basiri , Nazari F
Published: July 2011

This article presents a parametric study for and optimization of a transcritical power cycle. First, thermal efficiency, exergy efficiency, and specific network are selected as objective functions for parametric optimization. In order to optimize these functions, a procedure based on artificial neural networks (ANNs) and genetic algorithms (GAs) is proposed. This procedure comprises three steps. Step 1 is to find thermal efficiency, exergy efficiency, and specific network for different values of inlet turbine pressure, inlet turbine temperature, and fraction of the maximum power using the robust numerical code, engineering equation solver. In step 2, three distinct multi-layer perceptron ANNs based on the data obtained from step 1 are trained. In step 3, three distinct GAs are used to optimize the thermal efficiency, exergy efficiency, and specific network. The variables and fitness functions in these algorithms constitute, respectively, the inputs and outputs of the corresponding trained neural networks. For the purpose of validation of this study, for a special case, the results were compared with a previously reported case and were found to be in good agreement. Also in this article, this optimization process is applied to four different working fluids. Several interesting features among optimal objective functions and decision variables involved in the transcritical power cycle are identified.
Control of flexible joint robot manipulators using a combined controller with neural network and linear regulator
Authors: Jiang Z-H , Higaki S
Published: July 2011

This paper addresses the issue of dynamic trajectory tracking control of flexible joint robot manipulators. A new control strategy based on the technologies of linear feedback and neural network is proposed. It is well known that linear feedback controllers are simpler and easier to design, and neural networks have learning ability. These two advantages are utilized in order to deal with the control problems arising from non-linearity and dynamic instability of the flexible joint robot. The linear feedback control scheme is designed using optimal control approach, and the neural network is then designed based on the BP method and added to the control system. There are two different ways to add the neural network into the control system: being an additional regulator in parallel with the linear feedback controller, and being a dynamic compensator with some function of regulator. This leads to two different control systems. Performance of these two control systems are compared based on simulation results. Experiments are carried out using a two-link flexible joint robot as a test bed. The results demonstrate the effectiveness and usefulness of the proposed control method.
The sediments of the ‘Stagno di Maccarese’ marsh (Tiber river delta, central Italy): A late-Holocene record of natural and human-induced environmental changes
Authors: Giraudi Carlo
Published: July 2011

The environmental evolution, inferred from the sedimentary sequence, that has occurred during the last three millennia in a drained coastal marsh in the Tiber delta is presented. The stratigraphy of the sediments has been revealed through excavation of 7 km of trenches in an area of about 1.5 km2. The most evident environmental variations are represented by the transformation of freshwater marshes into brackish-water marshes, around the ninth–eighth centuries bc, and from brackish-water to freshwater marshes during the fourteenth–fifteenth centuries ad. The change in the water salinity was produced by the opening and closure of an inlet connecting the marshes and the sea because of the evolution of the delta. Other environmental variations are reflected in the fluctuations in the water level of brackish marshes: in a general trend towards an increase in water level, probably caused by the late-Holocene sea level increase, some phases of water decrease in the range of 10–20 cm occurred. The majority of the environmental changes were largely produced by erosion and sedimentary events connected with Tiber delta variations induced both by human impact and climate. The lower water levels were contemporary with glacial advances in the Alps and the Apennine chains. At least one of the five decreases of the water level was contemporaneous with a marine regression documented in Italy.
Health care usage in Dutch systemic lupus erythematosus patients
Authors: Zirkzee EJM , Steup-Beekman GM , Schouffoer AA , Henquet SM , Caljouw MAA , Huizinga TWJ , Vlieland TPM Vliet
Published: July 2011

As a first step in the improvement of the organization of care for patients with systemic lupus erythematosus (SLE) we studied their health care usage and its determinants. A questionnaire was sent to 161 outpatients of the rheumatology clinic of a Dutch university hospital. The questionnaire comprised questions on health care usage, quality of life and sociodemographic characteristics. Disease characteristics were extracted from the medical record. Among the 102 responders (63% response rate) the proportions of patients reporting contacts with a rheumatologist because of SLE since onset of the disease and over the past 12 months were 100% and 83%, respectively. These proportions were 93% and 68% for all other medical specialists, 88% and 44% for the general practitioner, 78% and 44% for any health professional, 29% and 9% for care at home, 48% and 17% for hospital admissions and 29% and 2% for day-patient care. Younger age, major organ involvement, the use of immunosuppressants and worse physical functioning were found to be significantly associated with greater health care use. This study demonstrated that health care usage by SLE patients is substantial and involves a variety of health care services. Further research should be directed at patients’ satisfaction and patients’ needs regarding the optimal organization of integrated, multidisciplinary services that are accessible for SLE patients of all ages.