bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of Iron Supplementation on Sexual Dysfunction of Women with Iron Deficiency Anemia in Short Term: A Preliminary Study
Authors: Gulmez Hakan , Akin Yigit , Savas Murat , Gulum Mehmet , Ciftci Halil , Yalcinkaya Soner , Yeni Ercan
Published: February 2014

Introduction

Iron deficiency anemia (IDA) is a common micronutrient deficiency worldwide. It is an important health problem especially in women of reproductive age. IDA may cause anxiety, which is the major factor for female sexual dysfunction (FSD).

Aim

The aim of the present study was to determine the impact of IDA on FSD in women of reproductive age.

Methods

In total, 207 women were enrolled. Women with IDA who were admitted in an outpatient clinic of family medicine were asked to complete Beck Anxiety Inventory (BAI), Female Sexual Function Index (FSFI), and Quality of Life (QoL) questionnaires. Questionnaires were completed before and after IDA treatments. Blood samples were obtained for measurements of hemoglobin, hematocrit, levels of serum iron, and iron-binding capacity.

Main Outcome Measures

Outcomes of blood samples were used for diagnosing of IDA. BAI, FSFI, and QoL scores were evaluated. Paired samples t-tests and Pearson correlation analyses were used to assess relationship between findings of IDA treatments and other parameters.

Results

The mean age was 33.6 ± 8.4 years. There were statistical significant differences between pre- and posttreatment in terms of hemoglobin, hematocrit, serum iron, and serum iron-binding capacity. BAI scores were decreased and FSFI scores, which were statistically significant, increased after IDA treatments (P < 0.001). However, QoL scores were developed without statistical significance.

Conclusion

There is a risk for anxiety as well as FSD in IDA women of reproductive age. Treatment of IDA can significantly improve sexual functions and QoL in these women population in short term.
Sleep problems: predictor or outcome of media use among emerging adults at university?
Authors: Tavernier Royette , Willoughby Teena
Published: February 2014

The pervasiveness of media use in our society has raised concerns about its potential impact on important lifestyle behaviours, including sleep. Although a number of studies have modelled poor sleep as a negative outcome of media use, a critical assessment of the literature indicates two important gaps: (i) studies have almost exclusively relied on concurrent data, and thus have not been able to assess the direction of effects; and (ii) studies have largely been conducted with children and adolescents. The purpose of the present 3‐year longitudinal study, therefore, was to examine whether both sleep duration and sleep problems would be predictors or outcomes of two forms of media use (i.e. television and online social networking) among a sample of emerging adults. Participants were 942 (71.5% female) university students (M = 19.01 years, SD = 0.90) at Time 1. Survey measures, which were assessed for three consecutive years starting in the first year of university, included demographics, sleep duration, sleep problems, television and online social networking use. Results of a cross‐lagged model indicated that the association between sleep problems and media use was statistically significant: sleep problems predicted longer time spent watching television and on social networking websites, but not vice versa. Contrary to our hypotheses, sleep duration was not associated with media use. Our findings indicate no negative effects of media use on sleep among emerging adults, but instead suggest that emerging adults appear to seek out media as a means of coping with their sleep problems.
ESTIMATION OF AUTOCOVARIANCE MATRICES FOR INFINITE DIMENSIONAL VECTOR LINEAR PROCESS
Authors: Bhattacharjee Monika , Bose Arup
Published: February 2014

Consider an infinite dimensional vector linear process. Under suitable assumptions on the parameter space, we provide consistent estimators of the autocovariance matrices. In particular, under causality, this includes the infinite‐dimensional vector autoregressive (IVAR) process. In that case, we obtain consistent estimators for the parameter matrices. An explicit expression for the estimators is obtained for IVAR(1), under a fairly realistic parameter space. We also show that under some mild restrictions, the consistent estimator of the marginal large dimensional variance–covariance matrix has the same convergence rate as that in case of i.i.d. samples.
Beyond Endogeneity: How Firms and Regulators Co‐Construct the Meaning of Regulation
Authors: Gilad Sharon
Published: February 2014

What role do regulators and firms play in the construction of open‐ended regulatory terms? The new institutionallegal endogeneitymodel posits that organizations respond to legal uncertainty by adopting formal structures to symbolically signal their compliance. These structures, however, tend to embody businesses' managerial and commercial values, as opposed to regulatory goals. Law becomes endogenous insofar as legal actors then defer to businesses' institutionalized ideas about regulation and compliance. Professionals, such as lawyers and human‐resource managers, and their strategic deployment of framing, are portrayed as the engines of the above process of legal endogeneity. By comparison, administrative agencies' strategies in shaping the meaning that corporations attach to the law are practically ignored. Building on a detailed case study ofBritish financial firms' responses to theFinancialServicesAuthority'sTreatingCustomersFairly initiative, this article problematizes the supposition of regulatory deference to business constructions of law. Instead, it develops a more balanced model that recognizes business professionals'andregulators'co‐constructionof regulation and compliance. The process of regulatory meaning co‐construction, as depicted by this model, involves alignment and disputes between regulators' and professionals' strategic framing of regulatory concerns with tangible consequences for the enactment of regulation.
Engineering a sensitive visual‐tracking reporter system for real‐time monitoring phosphorus deficiency in tobacco
Authors: Li Yiting , Gu Mian , Zhang Xiao , Zhang Jun , Fan Hongmei , Li Panpan , Li Zhaofu , Xu Guohua
Published: February 2014

Plant phosphorus (P) diagnosis is widely used for monitoring P status and guiding P fertilizer application in field conditions. The common methods for predicting plant response to P are time‐ and labour‐consuming chemical measurements of the extractable soil P and plant P concentrations. In this study, we successfully generated a visual reporter system in tobacco (Nicotiana tabacum L.) to monitor plant P status by expressing of a Purple gene (Pr) isolated from cauliflower (Brassica oleracea var botrytis) driven by the promoter (Pro) of OsPT6, a P‐starvation‐induced rice gene. The leaves of OsPT6pro::Pr (PT6pro::Pr) transgenic tobacco continuously turned into dark purple with the increase of duration and severity of P deficiency, and recovered rapidly to basal green colour upon resupply of P. The expression of several anthocyanin biosynthesis involving genes was strongly activated in the transgenic tobacco in comparison to wild type under P‐deficient condition. Such additive purple colour was not detected by deficiencies of other major‐ and micronutrients or stresses of salt, drought and cold. There was an extremely high correlation between P concentration and anthocyanin accumulation in the transgenic tobacco leaves. Using a hyperspectral sensing technology, P concentration in the leaves of transgenic plants could be predicted by the reflectance spectra at 554 nm wavelength with approximately 0.16 as the threshold value of the P deficiency. Taken together, the colour‐based visual reporter system could be specifically and readily used for monitoring the plant P status by naked eyes and accurately assessed by spectral reflectance.
Global health benefits of being raised in a rural setting: Results from the National Comorbidity Survey
Authors: Goodwin Renee D. , Taha Farah
Published: February 2014

Aim

The aim of this study was to examine the association between being raised in a rural setting and physical and mental health among adults in the USA.

Methods

Data were drawn from the National Comorbidity Survey (n = 8098), a household probability sample representative of adults aged 15–54 years in the USA. Multiple logistic regression analyses were used to determine the association between being raised in a rural area and the likelihood of mental disorders, physical disorders, suicide behavior, and parental mental health. Odds ratios (OR) with 95% confidence intervals were calculated, adjusting for differences in demographic characteristics.

Results

Being raised in a rural setting was associated with decreased odds of ulcer (OR = 0.56 [0.34, 0.91]). Mental disorders (any lifetime) (OR = 0.74 [0.64, 0.85]), any anxiety disorder (OR = 0.75 [0.6, 0.92]) and any substance use disorder (OR = 0.79 [0.65, 0.94]) were significantly less likely among adults who were raised in a rural setting. Maternal psychopathology and exposure to trauma were significantly lower among those raised in a rural setting, compared with those who were not. These relations were not explained by sociodemographic differences.

Conclusions

These data provide preliminary evidence that being raised in a rural environment lowers the risk of mental and physical health problems in adulthood. Being raised in a rural community also appears to be associated with significantly lower likelihood of exposure to trauma and maternal psychopathology. Future studies that can identify potential protective factors and mechanisms underlying these pathways are needed next.
Development of a Japanese version of the Reported and Intended Behaviour Scale: Reliability and validity
Authors: Yamaguchi Sosei , Koike Shinsuke , Watanabe Kei‐ichiro , Ando Shuntaro
Published: February 2014

Aim

The Reported and Intended Behaviour Scale (RIBS) was developed in the UK to measure mental health‐related behavior. The current study aimed to evaluate the applicability, and reliability of a Japanese version of the RIBS (RIBS‐J) in a Japanese context, and further examine the construct validity of the RIBS‐J.

Methods

The sample included 224 undergraduate and postgraduate students at a Japanese university. Cronbach's alpha was used to assess internal consistency. Pearson's correlation coefficient was used to examine the divergent validity between the RIBS‐J and the Mental Health Knowledge Schedule and the convergent validity between the second subscale of the RIBS‐J and Japanese version of the Social Distance Scale. Confirmatory factor analysis assessed the goodness of model fit of the RIBS‐J. We also examined test–retest reliability with another undergraduate sample (n = 29).

Results

Most items exhibited no floor/ceiling effect. High internal consistency (α = 0.83) was reported. The second subscale of the RIBS‐J, measuring intended behavior, correlated with the Mental Health Knowledge Schedule (r = 0.33, P < 0.001) and the Japanese version of the Social Distance Scale (r = −0.60, P < 0.001). In addition, confirmatory factor analysis found good model fit for the RIBS‐J (χ2 = 41.001, d.f. = 19, P = 0.002, goodness‐of‐fit index = 0.956, adjusted goodness‐of‐fit index = 0.916, comparative fit index = 0.955, root mean square error of approximation = 0.072). Overall test–retest reliability (ρc) was 0.71.

Conclusion

The RIBS‐J is an appropriate and psychometrically robust measure of behavior towards individuals with mental health problems in Japan. Further studies using a community sample could assess the generalizability of our findings.
Clinical characteristics and diagnostic confirmation of Internet addiction in secondary school students in Wuhan, China
Authors: Tang Jun , Zhang Yao , Li Yi , Liu Lianzhong , Liu Xiujun , Zeng Hongling , Xiang Dongfang , Li Chiang‐shan Ray , Lee Tony Szu‐Hsien
Published: February 2014

Aim

This study investigated the clinical characteristics of internet addiction using a cross‐sectional survey and psychiatric interview.

Methods

A structured questionnaire consisted of demographics, Symptom Checklist 90, Self‐Rating Anxiety Scale, Self‐Rating Depression Scale, and Young's Internet Addiction Test (YIAT) was administered to students of two secondary schools in Wuhan, China. Students with a score of 5 or higher on the YIAT were classified as having Internet Addiction Disorder (IAD). Two psychiatrists interviewed students with IAD to confirm the diagnosis and evaluate their clinical characteristics.

Results

Of a total of 1076 respondents (mean age 15.4 ± 1.7 years; 54.1% boys), 12.6% (n = 136) met the YIAT criteria for IAD. Clinical interviews ascertained the Internet addiction of 136 pupils and also identified 20 students (14.7% of IAD group) with comorbid psychiatric disorders. Results from multinomial logistic regression indicated that being male, in grade 7–9, poor relationship between parents and higher self‐reported depression scores were significantly associated with the diagnosis of IAD.

Conclusion

These results advance our understanding of the clinical characteristics of Internet addiction in Chinese secondary school students and may help clinicians, teachers, and other stakeholders better manage this increasingly serious mental condition.
Overexpression of the Brassica rapa transcription factor WRKY12 results in reduced soft rot symptoms caused by Pectobacterium carotovorum in Arabidopsis and Chinese cabbage
Authors: Kim H. S. , Park Y. H. , Nam H. , Lee Y. M. , Song K. , Choi C. , Ahn I. , Park S. R. , Lee Y. H. , Hwang D. J.
Published: February 2014

Chinese cabbage (Brassica rapa L. ssp. pekinensis), an important vegetable crop, can succumb to diseases such as bacterial soft rot, resulting in significant loss of crop productivity and quality. Pectobacterium carotovorum ssp. carotovorum (Pcc) causes soft rot disease in various plants, including Chinese cabbage. To overcome crop loss caused by bacterial soft rot, a gene from Chinese cabbage was isolated and characterised in this study. We isolated the BrWRKY12 gene from Chinese cabbage, which is a group II member of the WRKY transcription factor superfamily. The 645‐bp coding sequence of BrWRKY12 translates to a protein with a molecular mass of approximately 24.4 kDa, and BrWRKY12 was exclusively localised in the nucleus. Transcripts of BrWRKY12 were induced by Pcc infection in Brassica. Heterologous expression of BrWRKY12 resulted in reduced susceptibility to Pcc but not to Pseudomonas syringae pv. tomato in Arabidopsis. Defence‐associated genes, such as AtPDF1.2 and AtPGIP2, were constitutively expressed in transgenic lines overexpressing BrWRKY12. The expression of AtWKRY12, which is the closest orthologue of BrWRKY12, was down‐regulated by Pcc in Arabidopsis. However, the Atwrky12‐2 mutants did not show any difference in response to Pcc, pointing to a difference in function of WRKY12 in Brassica and Arabidopsis. Furthermore, BrWRKY12 in Chinese cabbage also exhibited enhanced resistance to bacterial soft rot and increased the expression of defence‐associated genes. In summary, BrWRKY12 confers enhanced resistance to Pcc through transcriptional activation of defence‐related genes.
Non‐Parametric Estimation of the Conditional Distribution of the Interjumping Times for Piecewise‐Deterministic Markov Processes
Authors: Azaïs Romain , Dufour François , Gégout‐Petit Anne
Published: February 2014

This paper presents a non‐parametric method for estimating the conditional density associated to the jump rate of a piecewise‐deterministic Markov process. In our framework, the estimation needs only one observation of the process within a long time interval. Our method relies on a generalization of Aalen's multiplicative intensity model. We prove the uniform consistency of our estimator, under some reasonable assumptions related to the primitive characteristics of the process. A simulation study illustrates the behaviour of our estimator.
Prenylation is required for polar cell elongation, cell adhesion, and differentiation in Physcomitrella patens
Authors: Thole Julie M. , Perroud Pierre‐Francois , Quatrano Ralph S. , Running Mark P.
Published: February 2014

Protein prenylation is required for a variety of growth and developmental processes in flowering plants. Here we report the consequences of loss of function of all known prenylation subunits in the moss Physcomitrella patens. As in Arabidopsis, protein farnesyltransferase and protein geranylgeranyltransferase type I are not required for viability. However, protein geranylgeranyltransferase type I activity is required for cell adhesion, polar cell elongation, and cell differentiation. Loss of protein geranylgeranyltransferase activity results in colonies of round, single‐celled organisms that resemble unicellular algae. The loss of protein farnesylation is not as severe but also results in polar cell elongation and differentiation defects. The complete loss of Rab geranylgeranyltransferase activity appears to be lethal in P. patens. Labeling with antibodies to cell wall components support the lack of polarity establishment and the undifferentiated state of geranylgeranyltransferase type I mutant plants. Our results show that prenylated proteins play key roles in P. patens development and differentiation processes.
Mechanism for Onset of Sudden-Rising Head Effect in Centrifugal Pump When Handling Viscous Oils
Authors: Li Wen-Guang
Published: February 2014

The “sudden-rising head effect” may be prevalent in the head curve when a centrifugal pump transports highly viscous liquids, but it is not well understood presently. To clarify this effect the hydraulic performance of centrifugal pump when handling water and viscous oils was evaluated numerically by using a CFD code. The “sudden-rising head effect” is confirmed to exist at a higher viscosity and a certain large surface roughness. The viscosity and roughness, which make a transition of boundary layer flow pattern in both the impeller and volute to the hydraulically smooth regime from the fully rough one, are responsible for the effect.
Experimental Investigation of the Relationship Between Lubricants' Tribological Properties and Their Lubricating Performances in Cold Rolling
Authors: Sun Jianlin , Yi Meirong , Sun Qiao , Lu Mingyu
Published: February 2014

In this paper, three lubricants are tested by a four-ball tribo-tester and in a cold rolling process. Our experimental results show that the data from the four-ball tests and the cold rolling tests are generally consistent with each other, implying the tribological properties measured by a four-ball tribo-tester are able to indicate the lubricants' lubricating performance in cold rolling reasonably well. Nevertheless, our experimental results also reveal certain discrepancies between the data from the four-ball tests and cold rolling tests. Especially, the friction coefficients from the four-ball tests are always considerably smaller than their counterparts from the cold rolling tests. Based on our analysis, the friction coefficients measured by cold rolling tests appear to be a more reliable indicator for the lubricants' performance in cold rolling than the friction coefficients measured by the four-ball tests.
Designing Aerostatic Bearing With Counterbalancing Gaps for Lifting a Heavy Payload
Authors: Mondal Nripen , Saha Rana , Sanyal Dipankar
Published: February 2014

An aerostatic bearing has been designed for supporting a heavy payload. The bearing involves an axial gap on the stator top that provides an upward lift, a bottom gap for counterbalancing the tendency of large lift-off, and a feeding orifice at the bearing inlet that is connected with the gaps by a network of holes or inherences yielding the damping. Notable contributions of the work are proving the concept by numerical simulation through first-principle order-separated modeling and evolving a simple solution strategy. The predicted vertical motion dynamics of the payload reveals that, depending on the target range of the payload weight, alternatives could be free or choked orifice designs.
Application of the Restoring Force Method for Identification of Lumbar Spine Flexion-Extension Motion Under Flexion-Extension Moment
Authors: Borkowski Sean L. , Ebramzadeh Edward , Sangiorgio Sophia N. , Masri Sami F.
Published: February 2014

The restoring force method (RFM), a nonparametric identification technique established in applied mechanics, was used to maximize the information obtained from moment-rotation hysteresis curves under pure moment flexion-extension testing of human lumbar spines. Data from a previous study in which functional spine units were tested intact, following simulated disk injury, and following implantation with an interspinous process spacer device were used. The RFM was used to estimate a surface map to characterize the dependence of the flexion-extension rotation on applied moment and the resulting axial displacement. This described each spine response as a compact, reduced-order model of the complex underlying nonlinear biomechanical characteristics of the tested specimens. The RFM was applied to two datasets, and successfully estimated the flexion-extension rotation, with error ranging from 3 to 23%. First, one specimen, tested in the intact, injured, and implanted conditions, was analyzed to assess the differences between the three specimen conditions. Second, intact specimens (N = 12) were analyzed to determine the specimen variability under equivalent testing conditions. Due to the complexity and nonlinearity of the hysteretic responses, the mathematical fit of each surface was defined in terms of 16 coefficients, or a bicubic fit, to minimize the identified (estimated) surface fit error. The results of the first analysis indicated large differences in the coefficients for each of the three testing conditions. For example, the coefficient corresponding to the linear stiffness (a01) had varied magnitude among the three conditions. In the second analysis of the 12 intact specimens, there was a large variability in the 12 unique sets of coefficients. Four coefficients, including two interaction terms comprised of both axial displacement and moment, were different from zero (p < 0.05), and provided necessary quantitative information to describe the hysteresis in three dimensions. The results suggest that further work in this area has the potential to supplement typical biomechanical parameters, such as range of motion, stiffness, and neutral zone, and provide a useful tool in diagnostic applications for the reliable detection and quantification of abnormal conditions of the spine.
Multitool and Multi-Axis Computer Numerically Controlled Accumulation for Fabricating Conformal Features on Curved Surfaces
Authors: Pan Yayue , Zhou Chi , Chen Yong , Partanen Jouni
Published: February 2014

In engineering systems, features such as textures or patterns on curved surfaces are common. In addition, such features, in many cases, are required to have shapes that are conformal to the underlying surfaces. To address the fabrication challenge in building such conformal features on curved surfaces, a newly developed additive manufacturing (AM) process named computer numerically controlled (CNC) accumulation is investigated by integrating multiple tools and multiple axis motions. Based on a fiber optical cable and a light source, a CNC accumulation tool can have multi-axis motion, which is beneficial in building conformal features on curved surfaces. To address high resolution requirement, the use of multiple accumulation tools with different curing sizes, powers, and shapes is explored. The tool path planning methods for given cylindrical and spherical surfaces are discussed. Multiple test cases have been performed based on a developed prototype system. The experimental results illustrate the capability of the newly developed AM process and its potential use in fabricating conformal features on given curved surfaces.
Fluid-Structure Interaction in Combustion System of a Gas Turbine—Effect of Liner Vibrations
Authors: Pozarlik A. K. , Kok J. B. W.
Published: February 2014

Prediction of mutual interaction between flow, combustion, acoustic, and vibration phenomena occurring in a combustion chamber is crucial for the reliable operation of any combustion device. In this paper, this is studied with application to the combustion chamber of a gas turbine. Very dangerous for the integrity of a gas turbine structure can be the coupling between unsteady heat release by the flame, acoustic wave propagation, and liner vibrations. This can lead to a closed-loop feedback system resulting in mechanical failure of the combustor liner due to fatigue and fatal damage to the turbine. Experimental and numerical investigations of the process are performed on a pressurized laboratory-scale combustor. To take into account interaction between reacting flow, acoustics, and vibrations of a liner, the computational fluid dynamics (CFD) and computational structural dynamics (CSD) calculations are combined into one calculation process using a partitioning technique. Computed pressure fluctuations inside the combustion chamber and associated liner vibrations are validated with experiments performed at the state-of-the-art pressurized combustion setup. Three liner structures with different thicknesses are studied. The numerical results agree well with the experimental data. The research shows that the combustion instabilities can be amplified by vibrating walls. The modeling approach discussed in this paper allows to decrease the risk of the gas turbine failure by prediction, for given operating conditions, of the hazardous frequency at which the thermoacoustic instabilities appear.
Extending the Transport Theorem to Rough Domains of Integration
Authors: Seguin Brian , Hinz Denis F. , Fried Eliot
Published: February 2014

Transport theorems, such as that named after Reynolds, are an important tool in the field of continuum physics. Recently, Seguin and Fried used Harrison's theory of differential chains to establish a transport theorem valid for evolving domains that may become irregular. Evolving irregular domains occur in many different physical settings, such as phase transitions or fracture. Here, emphasizing concepts over technicalities, we present Harrison's theory of differential chains and the results of Seguin and Fried in a way meant to be accessible to researchers in continuum physics. We also show how the transport theorem applies to three concrete examples and approximate the resulting terms numerically. Furthermore, we discuss how the transport theorem might be used to weaken certain basic assumptions underlying the description of continua and the challenges associated with doing so.
Thermal Pain in Teeth: Electrophysiology Governed by Thermomechanics
Authors: Lin Min , Genin Guy M. , Xu Feng , Lu TianJian
Published: February 2014

Thermal pain arising from the teeth is unlike that arising from anywhere else in the body. The source of this peculiarity is a long-standing mystery that has begun to unravel with recent experimental measurements and, somewhat surprisingly, new thermomechanical models. Pain from excessive heating and cooling is typically sensed throughout the body through the action of specific, heat sensitive ion channels that reside on sensory neurons known as nociceptors. These ion channels are found on tooth nociceptors, but only in teeth does the pain of heating differ starkly from the pain of cooling, with cold stimuli producing more rapid and sharper pain. Here, we review the range of hypotheses and models for these phenomena, and focus on what is emerging as the most promising hypothesis: pain transduced by fluid flowing through the hierarchical structure of teeth. We summarize experimental evidence, and critically review the range of heat transfer, solid mechanics, fluid dynamics, and electrophysiological models that have been combined to support this hypothesis. While the results reviewed here are specific to teeth, this class of coupled thermomechanical and neurophysiological models has potential for informing design of a broad range of thermal therapies and understanding of a range of biophysical phenomena.
A New Support Vector Machine and Artificial Neural Networks for Prediction of Stuck Pipe in Drilling of Oil Fields
Authors: Rostami Habib , Khaksar Manshad Abbas
Published: February 2014

Stuck pipe is known to be influenced by drilling fluid properties and other parameters, such as the characteristics of rock formations. In this paper, we develop a support-vector-machine (SVM) based model to predict stuck pipe during drilling design and operations. To develop the model, we use a dataset, including stuck and nonstuck cases. In addition, we develop radial-base-function (RBF) neural network based model, using the same dataset, and compare its results with the SVM model. The results show that the performance of both models for prediction of stuck pipe does not differ significantly and both of them have highly accurate and can be used as the heart of an expert system to support drilling design and operations.
Experiments on Natural Convective Solar Thermal Achieved by Supercritical CO2/Dimethyl Ether Mixture Fluid
Authors: Chen Lin , Zhang Xin-Rong
Published: February 2014

The current study proposed an experimental investigation into the basic characteristics of solar thermal conversion using supercritical CO2–dimethyl ether (DME) natural convection. The main goals are to reduce the operation pressure while maintaining relative high solar thermal conversion efficiency. Experimental systems were established and tested in Shaoxing area (around N 30.0 deg, E 120.6 deg) of Zhejiang Province, China. Due to the preferable properties of supercritical fluids, very high Reynolds number natural convective flow can be achieved. Typical summer day results are presented and analyzed into detail in this paper. It is found that the introduction of DME has successfully reduced the operation pressure and the increase in DME fraction leads to further reduction. Different from pure supercritical CO2 systems, the collector pressure follows the trend of solar radiation with its peak value at noon, instead of continuously increasing mode. The mass flow rate and temperature are typically more stable and also more sensitive than pure supercritical CO2 tests due to the moderation of supercritical fluid properties when DME is introduced. At the same time, the averaged collector efficiency is less affected by the DME mass addition. It is also found that there possibly exist some optimal of DME mass fraction when both the system suitability and stable natural circulation can be achieved.
SMA Actuated Vertical Blade Louver System: Part 1 — Performance Requirements and Design
Authors: Browne Alan L. , Johnson Nancy L. , Brown Jeffrey
Published: February 2014

Airflow over/under/around a vehicle can affect many important aspects of vehicle performance including vehicle drag (and through this vehicle fuel economy), vehicle lift and downforce, and cooling/heat exchange for the vehicle powertrain and A/C systems. While active devices are present on all aircraft, the majority of known airflow control devices in current use in ground transportation are of fixed geometry, location, orientation, and stiffness. The project, conducted during the 2004–2006 timeframe, whose performance requirements, design, and bench-top prototype build phases, are described in this paper was successful in developing an SMA actuator based approach for opening and closing a vertically-oriented-blade louver system to be used for on-demand control of the airflow into the engine compartment, i.e. for on-demand control of both cooling airflow as well as aerodynamic drag. Beyond feasibility, the initial full scale bench top working models demonstrated an active materials based approach which would have decreased weight and a smaller packaging envelop than a comparable motor driven unit. This demonstration showed that actuation speed, force, and cyclic stability all could meet the application requirements. The specific design that was selected, a set of parallel vertically oriented blades each linked through a gear to a common rack that is translated by a linear SMA actuator, uses straight linear actuation to produce a reversible synchronous 90 degree rotation of the blades, i.e. a full opening and closing capability for the louver system. Key technical issues that remained to be demonstrated and resolved through design modifications if necessary in Part 2 — on-vehicle performance testing — of this study were related in most part to robustness in the harsh vehicle front-end environment, a prime example being mechanism stalling due to ice or mud buildup.
Detecting Broken Reciprocating Compressor Valves in pV Diagrams of Different Valve Types
Authors: Pichler Kurt , Lughofer Edwin , Pichler Markus , Buchegger Thomas , Klement Erich Peter , Huschenbett Matthias
Published: February 2014

This paper presents a novel data-driven approach for detecting broken reciprocating compressor valves that is based on the idea that a broken valve will affect the shape of the pressure-volume (pV) diagram. This effect can be observed when the valves are closed. To avoid disturbances due to the load control we concentrate on the expansion phase linearized using the logarithmic pV diagram. The gradient of the expansion phase serves as an indicator of the fault state of the valves. Since the gradient is also affected by the pressure conditions, they are used as an additional indicator. After feature extraction and removing offset in the feature space by solving an optimization problem, classification of different valve types can be achieved with one support vector machine classifer. The performance of the method was validated by analyzing real-world measurement data. Our results show a very high classification accuracy for varying compressor load and pressure conditions.
Rapid Characterization of Shape Memory Alloy Material Parameters Using Computational Intelligence Methods
Authors: Henrickson James V. , Kirkpatrick Kenton , Valasek John
Published: February 2014

Shape memory alloys are capable of delivering advantageous solutions to a wide range of engineering-based problems. Implementation of these solutions, however, is often complicated by the hysteretic, non-linear, thermo-mechanical behavior of the material. Although existing shape memory alloy constitutive models are largely accurate in describing this unique behavior, they require prior characterization of the material parameters. Consequently, before thorough modeling and simulation can occur for a shape memory alloy-based project, one must first go through the process of identifying several material parameters unique to shape memory alloys. Current characterization procedures necessitate extensive experimentation, data collection, and data processing. As a result, these methods simultaneously create a high barrier of entry for engineers new to active materials and impede the advanced study of shape memory alloy material parameter evolution. This paper develops a novel method in which computational intelligence methods are used to rapidly identify shape memory alloy material parameters. Specifically, an artificial neural network is trained to identify transformation temperatures and stress influence coefficients of given shape memory alloy specimens using strain-temperature coordinates as inputs. After generating training data through the use of a constitutive model, the resulting trained artificial neural network was used to identify parameters for a number of randomly generated theoretical shape memory alloys. Results presented in the paper show that the artificial neural network was able to rapidly identify both transformation temperatures and stress influence coefficients with satisfactory accuracy. The generation of training data was then repeated using Taguchi methods. Further results presented in the paper show that the artificial neural network trained with the Taguchi-based training data yielded improved characterization accuracy while using less training data.
Adaptive Control Concept for Shape Memory Alloy Actuators
Authors: Pagel Kenny , Drossel Welf-Guntram , Zorn Wolfgang , Bucht André , Kunze Holger
Published: February 2014

Machine tools for small work pieces are characterized by an extensive disproportion between workspace and cross section. This is mainly caused by limitations in the miniaturization of drives and guidance elements, since their physical working principle necessitates certain minimum sizes. Due to their high specific workloads and relatively small spatial requirements, Thermal Shape-Memory-Alloys (SMA) possesses an outstanding potential to serve as miniaturized positioning devices in small machines. Antagonistically arranged SMA actuators are especially feasible to fulfill these requirements.

This paper describes an adaptive closed loop control concept for actuators based on spring loaded or antagonistic arrangements of electrically-heated SMA elements. Due to their nonlinear stress-strain behavior such actuators are characterized by strain dependent load conditions at the activated SMA element. Consequently the actuator dynamic depends on its position. Hence an adaptive closed loop control concept to ensure a constant actuator dynamic over the entire stroke has to be developed. The approach is based on the determination of the transient transfer dynamics of the SMA Element. Two possible strategies are investigated and evaluated. Numerical models of both SMA wire arrangements are used to develop the adaptive control theoretically. An SMA wire test bench is designed to investigate the proof of the adaptive approach experimentally. Measurements of a conventional PI control are further compared to the achieved results of the new concept.
Smart Crash Management by Switching the Crash Behavior of Fiber-Reinforced Plastic (FRP) Energy Absorbers With Shape Memory Alloy (SMA) Wires
Authors: Hübler Moritz , Nissle Sebastian , Gurka Martin , Schmeer Sebastian , Breuer Ulf Paul
Published: February 2014

In this paper two innovative concepts for adjustable energy absorbing elements are presented. These absorbers can serve as an essential element in a smart crash management system e.g. for automotive applications. The adaptability is based on the basic idea of adjusting the stiffness of the absorber in relation to the actual load level in a crash event. Therefore the whole length of the absorber element can be used for energy dissipation. The adjustable absorbers are made from fiber reinforced plastics and shape memory alloy wires as actuating elements. Two possibilities for the basic design of the absorber elements are shown, the performance of the actuating SMA elements is characterized in detail and the switching behavior of the whole elements, between a stiff “on” state and a flexible “off” state, is measured.
Design and Simulation of an MR Fluids-Based Haptic Actuator for Mobile Applications
Authors: Ryu Semin , Koo Jeong-Hoi , Yang Tae-Heon , Pyo Dongbum , Kyung Ki-Uk , Kwon Dong-Soo
Published: February 2014

This study presents a novel design of a miniature haptic actuator based on Magneto-Rheological (MR) fluids for mobile applications, and it evaluates the performance of a haptic actuator using a simulation model. The primary design goal for a haptic actuator for mobile applications is to miniaturize its size while generating realistic haptic sensations. To this end, this study proposes to design the MR actuator’s piston head (or plunger) in cone-shape and activate multiple modes of MR fluids (direct shear, flow and squeeze modes). Using a simulation model developed by integrating magnetic and force equations, the performance of a haptic actuator was evaluated in terms of the force (resistive force) produced by the actuator. The results show that a small actuator model, dimension of 10 mm (L) × 10 mm (W) × 6.5 mm (H), produced a maximum resistive force of about 5 N at 0.3 Watts, which is sufficient to provide force feedback to users.
Self-Powered Synchronized Switching Interfacing Circuits for Micro-Piezoelectric Energy Harvesters
Authors: Shih Ya Shan , Lin Shun Chiu , Lallart Mickaël , Wu Wen Jong
Published: February 2014

In this work, we have combined a micro-piezoelectric energy harvester with a dedicated interfacing circuit using the non-linear switch harvesting techniques based on the concept of SSH (synchronized switch harvesting). We especially focused on the power enhancement effect of the switching technique on micro-power generators. The micro-piezoelectric energy harvester that was used in this work is based on a stainless steel substrate, which largely improved the power output capability of the device. The resonant frequency of the energy harvesting device is 117 Hz, giving a voltage output of 3.85 V under the acceleration of 0.05 g. The overall size of the harvesting device is merely 8*6*0.5 mm3, including the proof mass. In order to further enhance the power generation abilities of the micro-generator, non-linear electrical interface circuits have also been designed and tested on two devices. According to the value of the figure of merit given by the product of the squared coupling coefficient k2 by the mechanical quality factor QM, a significant power gain compared to standard energy harvesting interface up to 3.13 has been tested for the device featuring a k2QM value of 0.17. A gain of 1.85 for a device with a k2QM value of 0.42 was also found. All of which were in good agreement with theoretical predictions. Furthermore, in order to be as close as possible to the realistic implementation of the micro-generators, the above mentioned nonlinear interface circuit were implemented in a self-powered design (i.e., without requiring an external energy source) using a very small part of the energy available generated from the piezoelectric energy harvester. Using the self powered technique, the overall system was available to provide 91.4 μW, with accelerations around 0.75 g, under the condition of k2QM = 0.72, and the power gain of 2.03.
Modeling and Control of a Continuously Variable Planetary Transmission for a Small Wind Turbine Drivetrain
Authors: Yang Zhi , Krishnamurthy Mahesh , Garcia Jose M.
Published: February 2014

This paper presents the modeling and control of a Continuously Variable Planetary (CVP) transmission in a wind turbine system. The primary purpose of this paper is to evaluate its effectiveness for mechanically decoupling the variable speed turbine rotor from the grid tied induction generator. It is expected that a CVP controlled wind turbine can take advantage of the grid tied induction generator without the use of an inverter, while optimizing the blade speed aerodynamically. This system also expands its operating range making it possible to track the optimal tip speed ratio over a wider wind speed range, which allows higher power to be captured from the wind. System characteristics have been studied by simulating an 8kW horizontal axis wind turbine in a MatLab/Simulink® environment. Experimental results have been included to verify the model of the system. Analyses conducted show that the continuously variable transmissions are potential candidates for small wind turbine applications.
Visions, Concepts and Strategies for Smart Nitinol Actuators and Complex Nitinol Structures Produced by Additive Manufacturing
Authors: Haberland Christoph , Elahinia Mohammad , Walker Jason , Meier Horst
Published: February 2014

This work covers different aspects of additive manufacturing of Nitinol parts. Firstly, requirements for the powder material and guidelines for the powder preparation are described in detail because the use of proper powder is essential for additive processing of high quality parts. Next, this work presents examples for Nitinol actuators, smart structures and devices which are produced by additive manufacturing. By demonstrating the functionality of these parts (e.g. shape recovery behavior after deformation), this work clearly points out a high potential for additive manufacturing of Nitinol. Moreover, additive manufacturing might even be able to open up new perspectives for Nitinol devices that have yet to be imagined.
The Validation of a Generalized Aerodynamic Model for a Multi-Body Bio-Inspired Wing
Authors: Blower Christopher J. , Wickenheiser Adam M.
Published: February 2014

Bio-inspiration has introduced new and innovative flow control methods in gust alleviation, maneuverability and stability improvement for morphing aircraft wings. The bio-inspired wing model under consideration imitates the techniques used by birds to manipulate localized air flow through the installation of feather-like panels across the airfoil’s upper and lower surface, replacing the traditional wing’s surface and trailing edge flap. Each flap is designed to rotate into both the airfoil profile and inbound air flow, using a single degree of freedom about their individual hinge points located at 20%, 40%, 60% and 80% of the chord. This wing morphing technique offers flap configurations typically unattainable by traditional aircraft and enables some advantageous maneuvers, including reduced turning radii and aero-braking. Due to the number of potential configurations, a generalized adaptive panel method (APM) has been developed to model the pressure distribution using a series of constant-strength doublets along the airfoil surface. To accommodate for the wake regions generated by the unconventional wing profiles, viscous Computational Fluid Dynamics (CFD) simulations are performed to characterize these regions and identify their outer boundaries. The wake profile geometries are integrated into the APM, and are used to accurately model the aerodynamic influence of the wake. To calculate the drag generated by each configuration, Thwaites’ laminar and Head’s turbulent boundary layer methods are implemented to enable identification of flow transition and separation along the airfoil surface. The integration of these aerodynamic techniques allows the flight characteristics, including the pressure, friction, lift, drag, and moment coefficients, of each morphing airfoil configuration to be calculated. The computed aerodynamic coefficients are validated using experimental data from a 4′×1′×1′ test section in a low speed suction wind tunnel operating over a Reynolds Number range of 150,000–450,000.
Non-Linear Piezoelectric Vibration Energy Harvesting From a Vertical Cantilever Beam With Tip Mass
Authors: Bilgen Onur , Faruque Ali S. , Friswell Michael I. , Litak Grzegorz , de Angelis Marc
Published: February 2014

An inverted cantilevered beam vibration energy harvester with a tip mass is evaluated for its electromechanical efficiency and power output capacity in the presence of pure harmonic, pure random and various combinations of harmonic and random base excitation cases. The energy harvester employs a composite piezoelectric material device that is bonded near the root of the beam. The tip mass is used to introduce non-linearity to the system by inducing buckling in some configurations and avoiding it in others. The system dynamics include multiple solutions and jumps between the potential wells, and these are exploited in the harvesting device. This configuration exploits the non-linear properties of the system using base excitation in conjunction with the tip mass at the end of the beam. Such nonlinear device has the potential to work well when the input excitation does not have a dominant harmonic component at a fixed frequency. The paper presents an extensive experimental analysis, results and interesting conclusions derived directly from the experiments supported by numerical simulations.