bluuebunny/crossref_metadata_2025 huggingface dataset:
Differing Cognitive Trajectories of Mexican American Toddlers
Authors: Fuller Bruce , Bein Edward , Kim Yoonjeon , Rabe-Hesketh Sophia
Published: February 2015

Recent studies reveal early and wide gaps in cognitive and oral language skills—whether gauged in English or Spanish—among Latino children relative to White peers. Yet, other work reports robust child health and social development, even among children of Mexican American immigrants raised in poor households, the so-called immigrant advantage. To weigh the extent to which Mexican heritage or foreign-born status contributes to early growth, we first compare levels of cognitive and communicative skills among children of Mexican American and native-born White mothers at 9 and 24 months of age, drawing from a national sample of births in 2001. Just one fifth of Mexican American toddlers kept pace with the cognitive growth of White toddlers at or above their mean rate of growth through 24 months of age, matched on their 9-month cognitive status. We then assess how factors from developmental-risk or ecocultural theory help to explain which Mexican American toddlers kept pace with White peers. Growth was stronger among toddlers whose family did not live beneath the poverty line, and whose mothers reported higher school attainment, more frequent learning activities, and exhibited steadier praise during a videotaped interaction task, factors more weakly observed among foreign-born Mexican American mothers. We found little evidence that foreign-born mothers exercised stronger home practices that advanced toddlers’ early cognitive growth as posited by immigrant-advantage theory. The positive factors emphasized by developmental-risk theory helped to explain variation in the cognitive growth of children of native-born, but not foreign-born, Mexican mothers.
Visual Outcome and Recurrence Rate in Children With Idiopathic Intracranial Hypertension
Authors: Ravid Sarit , Shahar Eli , Schif Aharon , Yehudian Shawn
Published: February 2015

The purpose of this retrospective study was to evaluate the visual outcome and recurrence rate of idiopathic intracranial hypertension in children. The study included 68 patients who were diagnosed with idiopathic intracranial hypertension according to the modified Dandy criteria. Permanent visual impairment was rare. Three percent remained with mild visual impairment, 4% with minimal visual field defects, and only 1 patient had severe visual impairment. However, 26% had either a prolonged course of disease or a recurring condition. Higher cerebrospinal fluid opening pressure was the only clinical predictor at presentation ( P = .04). Recurrence rate was 18%, and in most cases, the second episode occurred during the first year after remission. There was no significant difference between the group of patients with only 1 episode and the group of patients with more than 1 episode. We suggest long-term follow-up after remission, for at least a year, for all children with idiopathic intracranial hypertension.
Sleep Structure in Children With Attention-Deficit/Hyperactivity Disorder
Authors: Akinci Gulcin , Oztura Ibrahim , Hiz Semra , Akdogan Ozlem , Karaarslan Dilay , Ozek Handan , Akay Aynur
Published: February 2015

The authors evaluated basic sleep architecture and non–rapid eye movement (NREM) sleep alterations in drug-naïve attention-deficit/hyperactivity disorder (ADHD) children without psychiatric or other comorbidities. This cross-sectional case-control study included 28 drug-naïve children with ADHD and 15 healthy controls. This subjective studies revealed that children with ADHD had a worse sleep quality and increased daytime sleepiness. Polysomnography data showed that the sleep macrostructure was not significantly different in children with ADHD. Sleep microstructure was altered in ADHD children by means of reduced total cyclic alternating pattern rate and duration of cyclic alternating pattern sequences. This reduction was associated with a selective decrease of A1 index during stage 2 NREM. SpO2 in total sleep was slightly decreased; however, the incidence of sleep disordered breathing showed no significant difference. The authors suggest that cyclic alternating pattern scoring would provide a further insight to obtain a better understanding of the sleep structure in children with ADHD.
The Use of Modafinil in the Intensive Care Unit
Authors: Gajewski Michal , Weinhouse Gerald
Published: February 2015

As patients recover from their critical illness, the focus of intensive care unit (ICU) care becomes rehabilitation. Fatigue, excessive daytime somnolence (EDS), and depression can delay their recovery and potentially worsen outcomes. Psychostimulants, particularly modafinil (Provigil), have been shown to alleviate some of these symptoms in various patient populations, and as clinical trials are underway exploring this novel use of the drug, we present a case series of 3 patients in our institution’s Thoracic Surgery Intensive Care Unit. Our 3 patients were chosen as a result of their fatigue, EDS, and/or depression, which prolonged their ICU stay and precluded them from participating in physical therapy, an integral component of the rehabilitative process. The patients were given 200 mg of modafinil each morning to increase patient wakefulness, encourage their participation, and enable a more restful sleep during the night. Although the drug was undoubtedly not the sole reason why our patients became more active, the temporal relationship between starting the drug and our patients’ clinical improvement makes it likely that it contributed. Based on our observations with these patients, the known effects of modafinil, its safety profile, and the published experiences of others, we believe that modafinil has potential benefits when utilized in some critically ill patients and that the consequences of delayed patient recovery and a prolonged ICU stay may outweigh the risks of potential modafinil side effects.
Social Capital
Authors: Alawiyah Tuti , Held Mary Lehman
Published: February 2015

Social capital is positively associated with adult health and well-being. We know little, however, about the impact of social capital for women, especially those from developing nations. Knowledge of this relationship is important not only for women but also for social workers engaged with this population. This study examines the impact of social capital on the health and well-being of 6,099 women in Indonesia. Results indicate that education and trust positively correlate with health and well-being. The findings are relevant for social workers at a direct practice and programmatic level to offer services designed for improved health and well-being.
Casa Rut
Authors: Caretta Martina Angela
Published: February 2015

This article depicts the case study of Casa Rut (“Ruth Home”), a shelter for victims of sexual trafficking, who are predominantly Nigerian women. Since 1995, through the implementation of article 18 of the consolidated act on immigration, Casa Rut has offered a program of social assistance and rehabilitation to 340 women, 120 of whom were Nigerian and 41 of whom were pregnant. Data gathered during a 2-month internship between 2008 and 2009 are examined in light of the context of the Nigerian sexual trafficking operation and its collusion with the local criminal organization Camorra in the surroundings of the southern Italian city of Caserta. Casa Rut’s interventions are analyzed according to a multilevel perspective and the nature of victims’ case management in order to assess whether this nongovernmental organization can be considered to represent “good practice” in the fight against sexual trafficking. Hence, the work of the social cooperative NewHope—a tailoring cooperative founded in 2004 by Casa Rut that provides vocational training to formerly trafficked women—is considered in relation to the long-term employment needs of sexual trafficking victims. Human and sexual trafficking has not been extensively investigated within social work, even though practitioners are best positioned to address this issue. This work therefore aims to facilitate social service providers in their everyday activities by presenting multilevel evidence of good practice in the fight against the modern day slave trade.
Gender Differences in Capabilities for Work among Poor
Authors: Banerjee Mahasweta M.
Published: February 2015

Gender inequality is exceptionally high in India. It shows up through various explicit measures, but implicit disparities embedded in patriarchal norms are harder to measure. This article explores whether disparate freedoms between genders influence paid-work capabilities—abilities, skills, resources, and opportunities at personal, interpersonal, and structural levels. Using a mixed-methods design, purposive sampling, and face-to-face interviews, this article reports paid-work capabilities of 67 women and 25 men. The study finds statistically significant gender differences in some work capabilities; however, combined capabilities for work impact type of work and income more for women than for men. Implications are discussed.
Serious, Violent Young Offenders in South Africa
Authors: Souverein Fleur A. , Ward Catherine L. , Visser Ingmar , Burton Patrick
Published: February 2015

Life-course persistent offending contributes greatly to violent offending in any country. South Africa has high rates of violence; this study investigated what proportion of young South African offenders might be identified as life-course persistent, and what risk factors identified this group. Offenders aged 12 to 25 years ( N = 395) were selected from eight different correctional facilities in four provinces of South Africa. Latent class analysis identified 164 offenders (41.5%) with distinctly earlier starts and more serious offending. These (probably life-course persistent) offenders were distinguished from others by male gender, violence at home, other victimization, familial crime, school performance, violence at school, and alcohol abuse and gang membership. Correctional services should be specifically targeted at this large subgroup of offenders to prevent recidivism. Primary prevention efforts should be targeted at preventing violence at home and school, at promoting school attachment, at substance abuse treatment, and at gang membership.
The Role of Parent Communication and Connectedness in Dating Violence Victimization among Latino Adolescents
Authors: Kast Nicole Rebecca , Eisenberg Marla E. , Sieving Renee E.
Published: February 2015

Dating violence among U.S. adolescents is a substantial concern. Previous research indicates that Latino youth are at increased risk of dating violence victimization. This secondary data analysis examined the prevalence of physical and sexual dating violence victimization among subgroups of Latino adolescents and associations of parent communication, parent caring, and dating violence victimization using data from the 2010 Minnesota Student Survey ( N = 4,814). Parallel analyses were conducted for Latino-only and multiple-race Latino adolescents, stratified by gender. Multivariate logistic regression models tested associations between race/ethnicity, parent communication, perceived parent caring, and adolescent dating violence experiences. Overall, 7.2% to 16.2% of Latinos reported physical or sexual dating violence. Both types of dating violence were more prevalent among multiple-race Latinos than among Latino-only adolescents, with prevalence rates highest among multiple-race Latino females (19.8% and 19.7% for physical and sexual dating violence victimization, respectively). In multivariate models, perceived parent caring was the most important protective factor against physical and sexual dating violence among males and females. High levels of mother and father communication were associated with less physical violence victimization among males and females and with less sexual violence victimization among females. Results highlight the importance of parent communication and parent caring as buffers against dating violence victimization for Latino youth. These findings indicate potential for preventive interventions with Latino adolescents targeting family connectedness to address dating violence victimization.
Adverse Childhood Experiences and Arrest Patterns in a Sample of Sexual Offenders
Authors: Levenson Jill S. , Socia Kelly M.
Published: February 2015

Developmental psychopathology theories suggest that childhood adversity can contribute to antisocial conduct and delinquent activities. The purpose of this study was to explore the influence of adverse childhood experiences (ACE) on arrest patterns in a sample of sexual offenders ( N = 740). Higher ACE scores were associated with a variety of arrest outcomes, indicating that the accumulation of early trauma increased the likelihood of versatility and persistence of criminal behavior. Rapists of adults had higher ACE scores, lower levels of specialization, and higher levels of persistence than sex offenders with minor victims only. Child sexual abuse, emotional neglect, and domestic violence in the childhood home were significant predictors of a higher number of sex crime arrests. For measures of nonsexual arrests and criminal versatility, it was the household dysfunction factors—substance abuse, unmarried parents, and incarceration of a family member—that were predictive, suggesting that family dysfunction and a chaotic home environment contributed significantly to increased risk of general criminal behavior. Sex offenders inspire little sympathy in our society but may be among those most in need of trauma-informed models of treatment that recognize the influence of early adversity on maladaptive schema and self-regulation deficits related to criminal behavior.
More Polygraph Futility
Authors: Rosky Jeffrey W.
Published: February 2015

This article takes a critical look at the recent Jensen, Shafer, Roby, and Roby study that found that juveniles and adults have no statistically significant different rates of passing sexual history polygraph examinations. Numerous research and statistical issues are identified, including lack of independence, no adjustment for differing rates of opportunity across ages, poor construct validity of deceit, failure to adjust for base rates of deceit in subsequent analyses, and failure to include recidivism as an outcome. In addition, three arguments made by Jensen et al. against using recidivism as an outcome to judge post-conviction polygraph are discussed along with critical assessments of two recent studies examining the relationship between recidivism and sexual history polygraph examinations. It ends with a discussion of the current state of post-conviction polygraph testing research and way forward to find solid, replicable evidence that assesses its utility as a correctional intervention.
Profiles of Community Violence Exposure Among African American Youth
Authors: Gaylord-Harden Noni K. , Dickson Daniel , Pierre Cynthia
Published: February 2015

The current study employed latent class analysis (LCA) to identify distinct profiles of community violence exposure and their associations to desensitization outcomes in 241 African American early adolescents ( M age = 12.86, SD = 1.28) in the sixth through eighth grade from under-resourced urban communities. Participants self-reported on their exposure to community violence, as well as on depressive and anxiety symptoms. The LCA revealed three distinct classes: a class exposed to low levels of violence (low exposure class), a class exposed to moderately high levels of victimization (victimization class), and a class exposed to high levels of all types of violence (high exposure class). Consistent with predictions, the high exposure class showed the lowest levels of depressive symptoms, suggesting a desensitization outcome. Gender and age were also examined in relation to the classes, and age was significantly associated with an increased risk of being a member of the high exposure class relative to the low exposure class. Using person-based analyses to examine desensitization outcomes provides useful information for prevention and intervention efforts, as it helps to identify a specific subgroup of youth that may be more likely to show desensitization outcomes in the context of community violence.
Bullying and Peer Victimization
Authors: Radliff Kisha M. , Wang Cixin , Swearer Susan M.
Published: February 2015

Research has demonstrated a link between internalizing factors and bullying perpetration and peer victimization; however, few studies have examined predictors of cognitive and psychosocial factors, such as locus of control and hopelessness. The current study examined cognitive and psychosocial factors in bullying perpetration and peer victimization in a sample of 469 middle school students. A mediator model of hopelessness was also investigated. Students involved in bullying reported a greater external locus of control compared with peers who were not involved in bullying. Bully-victims endorsed the highest externality. Results showed that hopelessness fully mediated the relationship between verbal/relational victimization and external locus of control for the victim group, but not the bully-victim group. Implications for bullying prevention and intervention efforts are discussed.
Role of the Board Compensation Committee
Authors: Ellig Bruce R.
Published: February 2015

The role of the Board’s Compensation Committee is to approve the design of the pay programs for the top executive officers and to approve specific payments based on the plans and the company’s performance. Typically, the specific responsibilities of the compensation committee is specified within the company bylaws. This includes composition of the committee, statement of pay philosophy, implementation of plans approved by the board, identification of specific performance objectives, assessment of competitive pay practices, approval of employment contracts, role of external consultants, preparation of a Compensation Discussion and Analysis Report consistent with Securities and Exchange Commission requirements and filing a copy of the committee minutes to the board of directors and responding to their questions. Committee members have responsibility to put shareholder’s interest above their own (duty of loyalty), understanding the issues and alternatives (duty of care) and exercising prudent judgment (avoiding conflict of interest) and acting in good faith. These actions are required to meet the business judgment rule and avoid being held liable to their actions.
Reflections on the State of Workers’ Compensation and Occupational Health & Safety in the United States and Canada
Authors: Ison Terence G.
Published: February 2015

When an article similar to this one was published in Canada, it reflected primarily knowledge derived from firsthand experience in several provinces and territories, and empirical research in Ontario and British Columbia. Since that article was published in 2013, this new article reflects my research on recent publications in the United States on Workers’ Compensation. The article begins by explaining the damaging and overwhelming significance of experience rating. To enhance an understanding of current situations, the article then explains the legal history of Occupational Health & Safety and Workers’ Compensation. Then the role of physicians is discussed, particularly the difficulties they often have in distinguishing questions of law from questions of medicine. The article then deals with how decisions are made in the claims department of a Workers’ Compensation Board and by appeals tribunals. The practice of actuaries is explained, including the problems that their role creates. The limited role of judicial review is then mentioned, and finally the significance of the North American Free Trade Agreement and the World Trade Organization. The article concludes with conclusions and comments.
Using Cocreation to Engage Everyday Creativity in Reusing and Repairing Apparel
Authors: Lapolla Kendra , Sanders Elizabeth B.-N.
Published: February 2015

With textile waste growing, it is increasingly important to consider creative ways to reuse and repair clothing. The purpose of this study was to use co-creative methodology to explore what opportunities exist to encourage more personal creativity when reusing and repairing discarded clothing. The qualitative research uses levels of creativity (do, adapt, make and create) defined by Sanders (2005) as an initial framework for understanding the participants’ creativity and aspirations for reusing and repairing clothing. There is a growing desire to be creative, and the motivation and requirements drive the creativity for each individual (Sanders, 2005). Co-creative research methods were used in a series of qualitative visual interviews and creative workshops with women between 21-60 years old. The findings of this research supported co-creative research methods for textiles and apparel and revealed opportunities to encourage creativity in reusing and repairing clothing through participants’ ability to adapt their current wardrobes.
Sex Offender Supervision in Context
Authors: Bailey Danielle J. S. , Sample Lisa L.
Published: February 2015

Social distance, or the level of familiarity and rapport, within the officer–offender relationship is important in reducing recidivism and promoting desistance. Although examined in a variety of contexts, few researchers have studied the social distance between sex offenders and community supervision officers. When this has been examined, little attention has been paid to the legal and regulatory structure in place specifically for sex offenders or the cultural perceptions that citizens hold about sex offenders and sex offending. Within these structural and cultural contexts, we argue that sex offenders are a unique offender group, and thus, their relationships with supervision officers are likely qualitatively different from those formed between non-sex offenders and supervision officers. Using interviews with community supervision officers and convicted sex offenders, we highlight the structural and cultural contexts under which sex offenders are supervised and the ways in which the social distance in sex offender–officer relationships may vary from non-sex offender–officer relationships.
Overcoming Workplace Barriers
Authors: Johnson Angela Marie , Kirk Rosalind , Muzik Maria
Published: February 2015

Background:

Persistent racial disparities in breastfeeding show that African American women breastfeed at the lowest rates. Return to work is a critical breastfeeding barrier for African American women who return to work sooner than other ethnic groups and more often encounter unsupportive work environments. They also face psychosocial burdens that make breastfeeding at work uniquely challenging. Participants share personal struggles with combining paid employment and breastfeeding and suggest workplace and personal support strategies that they believe will help continue breastfeeding after a return to work.

Objective:

To explore current perspectives on ways to support African American mothers’ workplace breastfeeding behavior.

Methods:

Pregnant African American women (n = 8), African American mothers of infants (n = 21), and lactation support providers (n = 9) participated in 1 of 6 focus groups in the Greater Detroit area. Each focus group audiotape was transcribed verbatim. Thematic analysis was used to inductively analyze focus group transcripts and field notes. Focus groups explored thoughts, perceptions, and behavior on interventions to support African American women’s breastfeeding.

Results:

Participants indicate that they generally believed breastfeeding was a healthy option for the baby; however, paid employment is a critical barrier to successful breastfeeding for which mothers receive little help. Participants felt breastfeeding interventions that support working African American mothers should include education and training for health care professionals, regulation and enforcement of workplace breastfeeding support policies, and support from peers who act as breastfeeding role models.

Conclusion:

Culturally appropriate interventions are needed to support breastfeeding among working African American women.
Gender, age and flexible working in later life
Authors: Loretto Wendy , Vickerstaff Sarah
Published: February 2015

In many countries economic and social concerns associated with ageing populations have focused attention onto flexible forms of working as key to encouraging people to work longer and delay retirement. This article argues that there has been a remarkable lack of attention paid to the role of gender in extending working lives and contends that this gap has arisen because of two, inter-related, oversights: little consideration of relationships between gender and flexible working beyond the child-caring phase of life; and the prevailing tendency to think of end of working life and retirement as gender-neutral or following a typical male trajectory. The findings of a qualitative study of people aged 50+ in the UK challenge some of the key assumptions underpinning the utility of flexible work in extending working lives, and provide insight into the ways in which working in later life is constructed and enacted differently for men and women.
Rethinking job satisfaction in care work: looking beyond the care debates
Authors: Hebson Gail , Rubery Jill , Grimshaw Damian
Published: February 2015

Studies of care workers frequently reveal relatively high levels of job satisfaction despite poor employment conditions. The rewarding nature of care work, altruistic motivations and gendered social norms have all been used to explain why subjective job satisfaction is high despite poor pay and terms and conditions. Using data collected in case-study research with domiciliary and residential care workers, this article offers a new direction for care worker research that contextualizes the taken-for-granted assumption that care workers tolerate poor pay and conditions because women find the work satisfying and intrinsically rewarding. The article draws on cultural analyses of class to offer an alternative framework that identifies the wider social processes that can shape care workers’ job satisfaction.
Synthesis, characterization, and dye-sensitized solar cell fabrication using solid biopolymer electrolyte membranes
Authors: Singh Rahul , Singh Pramod K. , Tomar S. K. , Bhattacharya B.
Published: February 2015

Solid biopolymer-based electrolytes have been synthesized and characterized. Potassium iodide (KI) and iodine have been added in a biopolymer (sago palm) matrix to develop solid polymer electrolyte. Relationships between electrical and ionic transport parameters have been studied in detail, and the mechanism for ion transport has been proposed. Impedance spectroscopy reveals a significant enhancement in ionic conductivity by salt doping and the conductivity maxima was obtained at 50 wt% of KI concentration and also the system displays Arrhenius behavior. Dielectric phenomenon, mobility, charge carrier density, and diffusion coefficient also supports the conductivity data. Fourier transform infrared spectroscopy confirms the formation of a complex structure, while X-ray diffraction and optical microscopy affirms the complex structure as well as a reduction of crystallinity in the biopolymer electrolyte by salt doping. A dye-sensitized solar cell fabricated using fluorine-doped tin oxide–titanium dioxide (N3 dye)/maximum conducting electrolyte showed the short-circuit current density of 2.91 × 10−4 A cm−2, open-circuit voltage of 0.58 V, and efficiency of 0.57% at 1 sun condition.
The role of hydrophilic organoclay in morphology development of poly(butylene terephthalate)/polypropylene blends
Authors: Hajibaba Armin , Masoomi Mahmood , Nazockdast Hossein
Published: February 2015

This work is concerned with the effect of hydrophilic organoclay on morphology development of poly(butylene terephthalate) (PBT)/polypropylene (PP) blends. The concentration of nanoclays is varied from 1, 3, and 5 phr of polymer blend. Morphological analysis of nanocomposites shows a pronounced refinement of phase morphology with the reduction of droplet size, as compared to neat PBT/PP blend. With the aid of transmission electron microscopy, X-ray diffractometry, and rheological measurements, it is found that organoclays are exclusively located in PBT matrix and at the interface. The nonhomogeneous distribution of organoclays at the interface results in coalescence suppression of droplets and reduction of interfacial tension. Moreover, viscosity and elasticity of matrix are increased with the confinement of organoclays in PBT, which ends up with easier breakup of droplets. According to our research, using nanoclay changes the elasticity ratio of phases that affects capillary number and morphology of the blend. Our calculation indicates that the minimum size of dispersed droplets occurs at elasticity ratio of 1.92.
Preparation and characterization of cyanate/epoxy foam
Authors: Fan Chunchun , Tian Chunrong , Chen Keping , Gao Xia , Jia Xiaorong , Wang Jianhua
Published: February 2015

A new type of cyanate (CE)/epoxy (EP) foam with bisphenol-A dicyanate ester prepolymer and diglycidyl ether of bisphenol-A (BADCy/DGEBA) has been successfully prepared through a two-step process. The structure and properties of CE/EP foam were studied. The results reveal that the CE/EP foams, with relatively uniform cell structure, were composed of closed cells as confirmed by scanning electron microscopy. The compressive strength increased from 0.507 MPa to 3.021 MPa, and the compressive modulus ( E) increased from 15 MPa to 123 MPa as the density increased from 0.103 g cm−3 to 0.305 g cm−3. Dynamic mechanical analysis revealed that the CE/EP foams possessed a high glass transition temperature ( Tg) (203°C) and that density had only a little impact on Tg. Moreover, the excellent thermal stability presented with the onset of weight loss taken at 5% value was above 320°C, and the residual weight of the foam was more than 21.6% at 800°C. With increase in the density of CE/EP foams, the dielectric constants (ε) gradually decreased. For the foam with density of ρ = 0.162 g cm−3, the value of ε was as low as 2.28 at the frequency of 10 kHz.
Object recognition-based automated inspection system for hose assembly
Authors: Wen Peihan , Zheng Li , Yi Shuping
Published: February 2015

Computer vision–based inspection has been widely applied in automated quality inspection of lots of products. Extant research pays more attention to non-deformable parts, but little to deformable parts, such as hoses, which are popularly used in mechanical and electronic products to transport liquid because of advantages of deformability. Hence, a problem of automated inspection of hose assembly was defined and divided into four subproblems of online inspection, offline data analysis, improvement of inspection, and online quality control. Focusing on the first subproblem, a computer vision–based system was developed to deal with online inspection. Concerning the crucial unit of the system, objection recognition, features of hoses, and related fasteners were analyzed to present four propositions on shape and color constraints, and then a series of systematic techniques both in the spatial and spectral domains were put forward and discussed to perform image processing, object extraction, and feature recognition. Experiments show that average accuracies of object recognition and inspection are over 92% and even up to 100%, respectively, within an average running time of less than 30 s, which meets requirements of online inspection both on accuracy and efficiency. Since the system structure and corresponding methods are task-irrelevant, it can be generalized to figure out other inspection applications involving rotational parts.
Development of a paper-bag-folding machine using open architecture for adaptability
Authors: Zhao Chao , Peng Qingjin , Gu Peihua
Published: February 2015

Open architecture provides a sustainable product framework for mass personalised production. Applying personalised modules and common interfaces, an open-architecture product can satisfy changes in the user requirements of an application. Planning product modules for the open-architecture product structure using the existing method is challenging. The quality function deployment is extended in this study to decide the open-architecture product module types. The customer requirements are divided into two parts: basic function needs and changes of the individual customer needs. Based on the axiomatic design, the functional requirements are mapped into design parameters to establish the design matrix. A degree of variety is proposed as a quantitative measure for the component variability of product modules. According to the relationship of components and degree of variety, the product components are clustered into open-architecture product modules. The proposed method is used to design a paper-bag-folding machine to satisfy requirement changes during the machine application.
Modelling a contradiction-oriented design approach for innovative product design
Authors: Ko Yao-Tsung , Chen Ming-Shih , Yang Chih-Chieh , Zheng Meng-Cong
Published: February 2015

Without creativity in design, there is no potential for innovation. This article investigates the role of contradictions in enhancing creativity in product design. Based on the inventive principles of the Theory of Inventive Problem Solving, this article presents a novel design method by integrating technical and physical contradiction analysis methods into the conceptual design activities of new product development. Although the importance of innovative design is widely recognised, there is a lack of systematic and effective design-thinking processes that can cover all conceptual design activities. To address this gap, this study presents a clear problem-solving model to aid innovative product design based on the contradiction-oriented concept. A case study is employed to illustrate the proposed method, and the results demonstrate that it can help designers produce more creative outcomes in product design.
Tool design effect on microlubrication spray efficiency in milling using inner channels
Authors: Duchosal Arnaud , Serra Roger , Leroy René , Bonhoure David , Hamdi Hédi
Published: February 2015

This study consisted in investigating parameters that significantly influence the spray efficiency of minimum quantity lubrication in a milling tool with inner channels. An initial experimental approach was used to estimate the oil mist consumption and outlet particle velocities with different inlet pressures, for different shapes of inner channels, without rotation (static part). An experimental versus simulation comparison was undertaken between outlet velocities as a function of inlet pressure. The Reynolds-averaged Navier–Stokes model with the Lagrangian multiphase models was validated by comparing experimental and numerical outlet velocities for different inlet pressures. A numerical rotating tool with inner channels was used with the validated model in the second numerical simulation to analyze the influences of inlet conditions (inlet pressure) based on the tool shape and the rotation velocity, in a dynamic approach. The main objective of the oil mist is to reach the cutting edge (qualifying the minimum quantity lubrication spray efficiency) depending on the inlet conditions (inlet pressures) and the machining configurations (rotation velocities) by analyzing the streamlines of the oil mist particles. The study pointed out the tool design effect combined with its rotation velocity on the oil mist capability to reach the cutting edge. This study offered a trend of parameter sets to provide correct inlet parameters based on machining configurations. At high rotation speed, the inlet pressures needed to be high enough to counter the aerodynamic effects occurred by the tool design.
Experimental investigations on instability evolution in a transonic compressor at different rotor speeds
Authors: Li Qiushi , Pan Tianyu , Sun Tailu , Li Zhiping , Gong Yifang
Published: February 2015

Experimental investigations are conducted to study the instability evolution in a transonic axial flow compressor at four specific rotor speeds covering both subsonic and transonic operating conditions. Two routes of evolution to final instability are observed in the test compressor: at low rotor speeds, a disturbance in the rotor tip region occurs and then leads to rotating stall, while at high rotor speeds, a low-frequency disturbance in the hub region leads the compressor into instability. Different from stall and surge, this new type of compressor instability at high rotor speed is initiated through the development of a low-frequency axisymmetric disturbance at the hub, and we name it “partial surge”. The frequency of this low-frequency disturbance is approximately the Helmholtz frequency of the system and remains constant during instability inception. Finally, a possible mechanism for the occurrence of different instability evolutions and the formation of partial surge are also discussed.
Two-stage feature selection for bearing fault diagnosis based on dual-tree complex wavelet transform and empirical mode decomposition
Authors: Van Mien , Kang Hee-Jun
Published: February 2015

This paper presents an automatic fault diagnosis of different rolling element bearing faults using a dual-tree complex wavelet transform, empirical mode decomposition, and a novel two-stage feature selection technique. In this method, dual-tree complex wavelet transform and empirical mode decomposition were used to preprocess the original vibration signal to obtain more accurate fault characteristic information. Then, features in the time domain were extracted from each of the original signals, the coefficients of the dual-tree complex wavelet transform, and some useful intrinsic mode functions to generate a rich combined feature set. Next, a two-stage feature selection algorithm was proposed to generate the smallest set of features that leads to the superior classification accuracy. In the first stage of the two-stage feature selection, we found the candidate feature set using the distance evaluation technique and a k-nearest neighbor classifier. In the second stage, a genetic algorithm-based k-nearest neighbor classifier was designed to obtain the superior combination of features from the candidate feature set with respect to the classification accuracy and number of feature inputs. Finally, the selected features were used as the input to a k-nearest neighbor classifier to evaluate the system diagnosis performance. The experimental results obtained from real bearing vibration signals demonstrated that the method combining dual-tree complex wavelet transform, empirical mode decomposition, and the two-stage feature selection technique is effective in both feature extraction and feature selection, which also increase classification accuracy.
An approach of calculation on sliding friction power losses in involute helical gears with modification
Authors: Wang Cheng , Cui Huan Yong , Zhang Qing Ping , Wang Wen Ming
Published: February 2015

Sliding friction between the teeth is recognized as one of the main reasons of power losses in transmission as well as a potential reason of vibration and noise. A new approach is proposed to accurately calculate the sliding friction power losses in involute helical gears considered modification and geometric deviations resulting from the manufacturing processes, assembly errors, and deflections of support structures based on the simulation of gear mesh under light and significant load. Firstly, the paths of contact points on the pinion tooth surface are obtained from tooth contact analysis. Tooth surface load distributions and loaded transmission errors in one mesh period are obtained from loaded tooth contact analysis. Secondly, tooth surface load distributions are converted into the normal forces of tooth surface points of contact, loaded transmission errors are brought to the calculation formulas of sliding velocity, and the sliding friction coefficients of tooth surface points of contact are calculated by a non-Newtonian thermal elastohydrodynamic lubrication model. Substituting the sliding velocities, the normal forces, and the sliding friction coefficients into the power calculation formulas gives the sliding friction power losses of tooth surface points of contact. By the soft MATLAB, the values of the sliding friction power losses are integrated and the sliding friction power loss in helical gears from engagement to disengagement is obtained. Finally, an example of this approach is shown in the end. The results indicate that it is very necessary to consider the influence of loaded transmission errors for calculation of sliding friction power losses.
Design and optimization of a self-decoupled six-axis wheel force transducer for a heavy truck
Authors: Feng Lihang , Lin Guoyu , Zhang Weigong , Pang Han , Wang Tie
Published: February 2015

A wheel force transducer is a vital instrument in the vehicle-testing field which provides a means for determining experimentally the forces and the moments transmitted to a vehicle through the tyre contact patch. However, existing wheel force transducers are almost commercial products. They are expensive and, for business reasons, technical information is not made public. This slows down the development of the wheel force transducer itself to a certain extent. Moreover, research studies on the wheel force transducer mainly focus on utilization of this tool for vehicle simulations, traction control and anti-lock braking evaluation as it provides information on the characteristics, the performance and the limitations of the vehicle. From the perspective of the sensor itself, although improvement in the transducer accuracy and information extraction using signal-processing methods have been successfully developed in the literature, few investigations on the design of the wheel force transducer have been reported yet. Accordingly, a general design and optimization procedure for the wheel force transducer with a practical case study will be of great significance. Since technical difficulties, admittedly, are primarily about the issues of how to design and optimize the transducer, in this paper a new self-decoupled six-axis wheel force transducer for a heavy truck is designed and fabricated. An easy-to-understand design procedure is highlighted mainly including the conceptual design with the aims of a universal-purpose self-decoupled transducer with an eight-spoke structure, an optimization design which depends on the proposed comprehensive performance criteria in the computer-aided procedure, and a collectivity design focus on the mechatronics assembly for a heavy-truck application. Finally, the wheel force transducer is manufactured, calibrated and tested. The results show that the mean errors of the six-axis forces are about 3% of the full scale with 1% non-linearity, 0.5% repeatability and 1% hysteresis for the sensor only, that there are increased mean values of about 2% non-linearity, 1% repeatability and 1.4% for a certain tyre assembly and that the observed dynamic response is about 2.5–3.5 ms. Both the self-decoupled characteristics and the sensor performance are verified to meet the design and optimization, and the transducer with a real-time wheel force output is also confirmed by road tests.
Hardware-in-the-loop simulations of an electrohydraulic power steering system for developing the motor speed map of heavy commercial vehicles
Authors: Kim Seong Han , Chu Chong Nam
Published: February 2015

This study proposes hardware-in-the-loop simulations to develop the motor speed map of electrohydraulic power steering systems for heavy commercial vehicles. The current method that relies on the test driver’s hands and feet to obtain electrohydraulic power steering motor speed maps causes a number of problems, such as inaccurate steering rates and vehicle speeds and the risk of rollover during tests. In order to overcome these weaknesses, this study employs a hardware-in-the-loop simulation system, a vehicle model, and an experimental development method. A hardware-in-the-loop simulation system was set up to simulate a steering system on the road. The system includes a system drive, data acquisition, system controller sets, and an electrohydraulic power steering system. This hardware-in-the-loop simulation system is controlled in real time because the amount of the torque from the resistant torque motor, which applies the self-aligning moments generated between the ground and the tires to the steering system, is affected by the steering angle of the steering-wheel motor. For calculation of the resistant torque with respect to various driving conditions, a vehicle model was employed in this study. It includes calculation of the self-aligning moments with the tire property data, the moments due to the kingpin inclination, the vehicle dynamics, and the steering-system modeling. The resultant values were input into the resistant torque motor. In addition to the hardware-in-the-loop simulation system and the vehicle model, the concept of a desirable steering torque which parameterizes the steering feel was introduced in this study. Using the desirable steering torque, the steering feel could be quantified, and desirable steering feels were established. In this study, in order to validate the hardware-in-the-loop simulations, a heavy commercial vehicle was designated as the target vehicle. The target vehicle’s tire and specifications such as the dimensions, the weight, the steering system, and the mechanical links were adopted, and a desirable steering-torque map was established by a professional test driver. The development results were presented.
One-dimensional simulations and experimental analysis of a wastegated turbine for automotive engines under unsteady flow conditions
Authors: De Bellis Vincenzo , Marelli Silvia
Published: February 2015

In this paper, the unsteady-state behaviour of a turbocharger wastegated turbine (IHI-RHF3) is investigated using both an experimental approach and a numerical approach. First, an experimental campaign is performed in a specialized test rig operating at the University of Genoa, for different openings of the wastegate valve and under steady flow and unsteady flow operations. An appropriate configuration of the turbine outlet circuit fitted with a separating wall is used to carry out instantaneous measurements downstream of the turbine wheel and the wastegate valve. The above data constitute the basis for the tuning and validation of a one-dimensional turbine model recently developed at the University of Naples. Preliminary model tuning is carried out on the basis of the characteristic map measured for a completely closed wastegate valve under steady flow operations. A refined one-dimensional schematization of the experimental apparatus is implemented within the commercial GT-Power® software, including the turbine, the wastegate circuit and the upstream and downstream measuring stations. In particular, the classical map-based approach is suitably corrected with a sequence of pipes that schematizes each component of the turbine (the inlet and outlet ducts, the volute and the wheel) to account for the wave propagation and storage phenomena inside the machine. A detailed one-dimensional schematization of the wastegate circuit is also implemented and independently tuned. The turbine model capability under unsteady flow conditions is tested for different wastegate openings and pulse frequencies, by applying time-dependent boundary conditions. In particular, the pressures and temperatures measured upstream and downstream are imposed at the model ends, and the instantaneous mass flow rate and the actual power are numerically evaluated. The results are compared with the experimental data, demonstrating good accuracy and showing some improvements with respect to the standard turbine modelling in the case of the mass flow rate prediction. On the contrary, the computed actual power shows some inaccuracies, especially at higher pulse frequencies.