bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of Xiphophorus and human melanoma transcriptomes reveals conserved pathway interactions
Authors: Lu Yuan , Boswell Mikki , Boswell William , Kneitz Susanne , Hausmann Michael , Klotz Barbara , Regneri Janine , Savage Markita , Amores Angel , Postlethwait John , Warren Wesley , Schartl Manfred , Walter Ronald
Published: January 2018

Comparative analysis of human and animal model melanomas can uncover conserved pathways and genetic changes that are relevant for the biology of cancer cells. Spontaneous melanoma in Xiphophorus interspecies backcross hybrid progeny may be informative in identifying genes and functional pathways that are similarly related to melanoma development in all vertebrates, including humans. To assess functional pathways involved in the Xiphophorus melanoma, we performed gene expression profiling of the melanomas produced in interspecies BC1 and successive backcross generations (i.e., BC5) of the cross: X. hellerii × [X. maculatus Jp 163 A × X. hellerii]. Using RNA‐Seq, we identified genes that are transcriptionally co‐expressed with the driver oncogene, xmrk. We determined functional pathways in the fish melanoma that are also present in human melanoma cohorts that may be related to dedifferentiation based on the expression levels of pigmentation genes. Shared pathways between human and Xiphophorus melanomas are related to inflammation, cell migration, cell proliferation, pigmentation, cancer development, and metastasis. Our results suggest xmrk co‐expressed genes are associated with dedifferentiation and highlight these signaling pathways as playing important roles in melanomagenesis.
Doing the math: A simple approach to topical timolol dosing for infantile hemangiomas
Authors: Dalla Costa Renata , Prindaville Brea , Wiss Karen
Published: January 2018

Topical timolol maleate has recently gained popularity as a treatment for superficial infantile hemangiomas, but calculating a safe dose of timolol can be time consuming, which may limit the medication's use in fast‐paced clinical environments. This report offers a simplified calculation of the maximum daily safe dosage as 1 drop of medication per kilogram of body weight.
Exogenous Cushing syndrome due to misuse of potent topical steroid
Authors: Özgüç Çömlek Fatma , Örüm Sevim , Aydın Salih , Tütüncüler Filiz
Published: January 2018

We report an infant with exogenous Cushing syndrome after being treated for 2 months with a potent topical corticosteroid via the mother's application of topical clobetasol for diaper rash without a prescription. We emphasize that potent topical steroids should be used with great caution, especially when used under occlusion (e.g., diaper area) and that parents should be warned about potential side effects of these medications, particularly when used in infants.
Psychosocial functioning in pediatric heart transplant recipients and their families
Authors: Cousino Melissa K. , Schumacher Kurt R. , Rea Kelly E. , Eder Sally , Zamberlan Mary , Jordan Jessica , Fredericks Emily M.
Published: January 2018

Across pediatric organ transplant populations, patient and family psychosocial functioning is associated with important health‐related outcomes. Research has suggested that pediatric heart transplant recipients and their families are at increased risk for adverse psychosocial outcomes; however, recent investigation of psychosocial functioning in this population is lacking. This study aimed to provide a contemporary characterization of psychosocial functioning in pediatric heart transplant recipients and their families. Associations between psychosocial function, demographic variables, and transplant‐related variables were investigated. Fifty‐six parents/guardians of pediatric heart transplant recipients completed a comprehensive psychosocial screening measure during transplant follow‐up clinic visits. Descriptive statistics, correlational analyses, and independent samples t tests were performed. Forty percent of pediatric heart transplant recipients and their families endorsed clinically meaningful levels of total psychosocial risk. One‐third of patients presented with clinically significant psychological problems per parent report. Psychosocial risk was unassociated with demographic or transplant‐related factors. Despite notable improvements in the survival of pediatric heart transplant recipients over the past decade, patients and families present with sustained psychosocial risks well beyond the immediate post‐transplant period, necessitating mental health intervention to mitigate adverse impact on health‐related outcomes.
Group 1 innate lymphoid cells in Toxoplasma gondii infection
Authors: Dunay I. R. , Diefenbach A.
Published: January 2018

Innate lymphoid cells (ILCs) are a group of lymphocytes that carry out important functions in immunity to infections and in organ homeostasis at epithelial barrier surfaces. ILCs are innate immune cells that provide an early source of cytokines to initiate immune responses against pathogens. Cytotoxic ILCs (i.e. conventional (c)NK cells) and several subsets of helper‐like ILCs are the major branches of the ILC family. Conventional NK cells and group 1 ILCs share several characteristics such as surface receptors and the ability to produce IFN‐γ upon activation, but they differ in their developmental paths and in their dependence on specific transcription factors. Infection of mice with the intracellular parasite Toxoplasma gondii is followed by a strong Th1‐mediated immune response. Previous studies indicate that NK1.1+ cells contribute to the production of IFN‐γ and TNF and cytotoxicity during acute T. gondii infection. Upon oral infection, the parasite infects intestinal enterocytes, and within the lamina propria, innate immune responses lead to initial parasite control although the infection disseminates widely and persists long‐term in immune privileged sites despite adaptive immunity. Upon parasite entry into the small intestine, during the acute stage, ILC1 produce high levels of IFN‐γ and TNF protecting barrier surfaces, thus essentially contributing to early parasite control. We will discuss here the role of innate lymphocytes during T. gondii infection in the context of the only recently appreciated diversity of ILC subsets.
Running Behavioral Operations Experiments Using Amazon's Mechanical Turk
Authors: Lee Yun Shin , Seo Yong Won , Siemsen Enno
Published: January 2018

Mechanical Turk (MTurk), an online labor market run by Amazon, provides a web platform for conducting behavioral experiments; the site offers immediate and inexpensive access to a large subject pool. In this study, we review recent research about using MTurk for behavioral experiments and test the validity of using MTurk for experiments in behavioral operations management. We recruited subjects from MTurk to replicate the inventory management experiment from Bolton and Katok ( 2008 ), as well as the procurement auction experiment from Engelbrecht‐Wiggans and Katok ( 2008 ), and the supply chain contracting experiment from Loch and Wu ( 2008 ). We successfully replicate individual biases in the inventory management and procurement auction experiments, but learning in the individual tasks occurs more slowly on MTurk compared to the original studies. Further, we find that social preference manipulations in the supply chain experiment are ineffective in changing the behavior of MTurk subjects, in contrast to the original study. We conducted an additional replication study of the supply chain contracting experiment using student subjects in a standard laboratory. Results from this laboratory replication also fail to replicate the original laboratory study, indicating that the effect of social preferences on supply chain contracting may not be robust to alternative subject pools. We conclude that factors potentially influencing the differences observed on MTurk are less related to the online environment, but more related to the diversity and characteristics of subject pool on MTurk. Overall, MTurk appears to be an important and relevant tool for researchers in behavioral operations, but we caution researchers about slower learning of the MTurk subjects and the use of social preference manipulations on MTurk.
Advertising Competition on the Internet: Operational and Strategic Considerations
Authors: Liu Dengpan , Mookerjee Vijay
Published: January 2018

The emerging click‐based pricing models for Internet advertising provide the firm with two possible decision processes to manage an advertising campaign, namely, spending‐based and traffic‐based. The spending‐based process starts with the spending budget and determines the traffic accordingly, whereas the traffic‐based process starts with a target level of traffic and determines the spending budget accordingly. We consider a duopoly where two electronic retailing firms—that compete for customer traffic—make demand generation (advertising) and demand fulfillment (IT capacity) decisions in equilibrium. Our analysis shows that the inclusion of operational considerations softens the level of competition between the firms and is better for both firms. Concerning the decision process, we find that traffic‐based competition generates higher profits for both firms than those generated in spending‐based competition. However, when the decision process is itself a choice, a spending‐based advertising is chosen by both firms in equilibrium. We discuss how managers can be strategic about the choice of the decision process when competing for customer traffic.
Respiratory symptoms and small airway dysfunction in current and former smokers without spirometric COPD
Authors: Thomson Neil C
Published: January 2018

See related Article
Location choices and third‐degree spatial price discrimination
Authors: Feng Hong , Ma Jie
Published: January 2018

This paper studies how firms choose their product differentiation levels when they engage in third‐degree price discrimination in the following product market competition in a location‐price model. We show that firms will not choose to locate at the two endpoints if different consumer groups have similar sizes. Hence, the principle of maximum differentiation does not hold, resulting in a more intense product market price competition. Only if the size of one group of consumers is sufficiently larger than that of the other group, would firms make their products as differentiated as possible by choosing the two endpoints as their locations.
Enhancing Formative Assessment Practice and Encouraging Middle School Mathematics Engagement and Persistence
Authors: Beesley Andrea D. , Clark Tedra F. , Dempsey Kathleen , Tweed Anne
Published: January 2018

In the transition to middle school, and during the middle school years, students' motivation for mathematics tends to decline from what it was during elementary school. Formative assessment strategies in mathematics can help support motivation by building confidence for challenging tasks. In this study, the authors developed and piloted a professional development program, Learning to Use Formative Assessment in Mathematics with the Assessment Work Sample Method (AWSM) to build middle school math teachers' understanding of the characteristics of high‐quality formative assessment processes and increases their ability to use them in their classrooms. AWSM proved to be feasible to implement in the middle school setting. It improved teachers' practice of formative assessment, especially in their feedback practices, regardless of their pedagogical content knowledge at entry. Results from focus groups suggested that teachers were better able to implement ungraded practice and student self‐ and peer‐assessment after AWSM, and that students were more willing to engage in complex problem solving.
The full‐length sequence of the HLA‐C allele, HLA‐C*15:13:01:01
Authors: Li Z. , Zou H.‐Y. , Zhou D.
Published: January 2018

Confirmed the full‐length sequence of HLA‐C*15:13:01:01 by cloning and sequencing in a Chinese donor.
Percutaneous prick test irritant threshold concentrations for eight allergens in healthy nonsedated dogs in the USA
Authors: Carnett Matthew J.H. , Plant Jon D.
Published: January 2018

Background

Percutaneous testing (PT) is preferred to intradermal testing in humans for the in vivo identification of allergen hypersensitivity, but the methodology has not been well described for use in dogs with atopic dermatitis.

Hypothesis/Objectives

To identify the irritant threshold concentrations (ITC) of eight aeroallergens using a commercial prick test device in normal dogs.

Animals

Twenty healthy, privately owned dogs.

Methods

Percutaneous testing was performed using the GREER® Pick® System (Stallergenes Greer; Lenoir, NC, USA). Five dilutions of glycerinated extracts of Bromis inermis, Sorghum halepense, Chenopodium album, Ambrosia psilostachya, Salix nigra and Acer negundo, as well as four dilutions of Dermatophagoides farinae and D. pteronyssinus were included. Glycerinated histamine (6 mg/ml) and glycerin/Coca's solution were used for the positive and negative controls, respectively. Orthogonal wheal diameters were measured for each test site every 5 min for 25 min. Reactions were considered significant when the average wheal diameter was equal to or greater than the mean of the positive and negative controls.

Results

Significant reactions were noted in five of 20 (25%) of dogs. The ITC (≤10% of dogs reacting) were 1:20 w/v for B. inermis and S. nigra, 1:400 w/v for D. farinae and 1:200 w/v for D. pteronyssinus.

Conclusions and clinical importance

These results suggest that the pollen allergens evaluated in this study can be used for PT at their undiluted concentration (1:20 w/v) with a reasonable assurance of few false positive reactions in dogs. Dust mites require dilution for testing at the ITC.
A multicentred study to validate a consensus bleeding assessment tool developed by the biomedical excellence for safer transfusion collaborative for use in patients with haematological malignancy
Authors: Dyer C. , Alquist C. R. , Cole‐Sinclair M. , Curnow E. , Dunbar N. M. , Estcourt L. J. , Kaufman R. , Kutner J. M. , McCullough J. , McQuilten Z. , Potiphar L. , Rioux‐Masse B. , Slichter S. , Tinmouth A. , Webert K. , Yokoyama A. P. , Stanworth S. J. ,   the BEST Collaborative
Published: January 2018

Background

There continues to be uncertainty about the optimal approach to documenting bleeding data in platelet transfusion trials, with a desire to apply a common assessment tool across all trials. With this in mind, a consensus bleeding assessment tool (BAT) has been developed by the Biomedical Excellence for Safer Transfusion (BEST) collaborative, based on review of data collection forms used in published randomized trials and following content validation with a range of healthcare professionals at seven haematology centres through BEST members. This study aimed to evaluate reliability and reproducibility of the consensus BAT.

Methods

Replicated clinical assessments of bleeding were undertaken by participants with haematological malignancies recruited at four haematology centres in an international, multicentred, observational study. Concordance of repeat assessments was calculated for agreement in site and grade of bleeding observed.

Results

Forty patients consented to participate, and 13 trained bleeding assessors collected these data. Bleeding assessments were carried out on 113 separate days. Of all 225 bleeding assessments, 204 were compared for grade concordance, and 160 were compared for site concordance. There was very good grade concordance (83%, 95% confidence interval 74–93%) and good bleeding site concordance (69%, 95% confidence interval 57–79%) in observations of bleeding. Discordance was primarily in relation to assessing skin bleeding.

Conclusions

Alongside a structured training programme, levels of concordance for a consensus BAT were high. Researchers using assessment tools for bleeding need to balance comprehensive data collection against potential loss of accuracy for some types of bleeding, such as skin findings.
The efficacy of basic fibroblast growth factor‐loaded poly(lactic‐co‐glycolic acid) nanosheet for mouse wound healing
Authors: Aoki Shimpo , Fujii Mao , Fujie Toshinori , Nishiwaki Keisuke , Miyazaki Hiromi , Saitoh Daizoh , Takeoka Shinji , Kiyosawa Tomoharu , Kinoshita Manabu
Published: January 2018

Although human recombinant basic fibroblast growth factor (bFGF) is widely used for wound healing, daily treatment with bFGF is required because of its short half‐life. An effective controlled‐release system of bFGF is, therefore, desired in clinical settings. To investigate the efficacy of a bFGF‐loaded nanosheet for wound healing, focusing on the controlled‐release of bFGF, bFGF‐loaded poly(lactic‐co‐glycolic acid) (PGLA) nanosheets were developed, and their in vitro release profile of bFGF and their in vivo efficacy for wound healing were examined. A polyion complex of positively charged human recombinant bFGF and negatively charged alginate was sandwiched between PLGA nanosheets (70 nm thick for each layer). The resulting bFGF‐loaded nanosheet robustly adhered to silicon skin by observation using a microscratch test. bFGF was gradually and continuously released over three days in an in vitro incubation study. Treatment with the bFGF‐loaded nanosheets (every 3 day for 15 days) as well as with a conventional bFGF spray effectively promoted wound healing of mouse dorsal skin defects with accelerated tissue granulation and angiogenesis, although the dose of bFGF used in the treatment with the bFGF nanosheets was approximately 1/20 of the sprayed bFGF. In conclusion, we developed a bFGF‐loaded nanosheet that sustained a continuous release of bFGF over three days and effectively promoted wound healing in mice.
Effect of Eukarion‐134 on Akt–mTOR signalling in the rat soleus during 7 days of mechanical unloading
Authors: Kuczmarski J. Matthew , Hord Jeff M. , Lee Yang , Guzzoni Vinicius , Rodriguez Dinah , Lawler Matthew S. , Garcia‐Villatoro Erika L. , Holly Dylan , Ryan Patrick , Falcon Kristian , Garcia Marcela , Janini Gomes Mariana , Fluckey James D. , Lawler John M.
Published: January 2018

New Findings

What is the central question of this study?

Translocation of nNOSμ initiates catabolic signalling via FoxO3a and skeletal muscle atrophy during mechanical unloading. Recent evidence suggests that unloading‐induced muscle atrophy and FoxO3a activation are redox sensitive. Will a mimetic of superoxide dismutase and catalase (i.e. Eukarion‐134) also mitigate suppression of the Akt–mTOR pathway?

What is the main finding and its importance?

Eukarion‐134 rescued Akt–mTOR signalling and sarcolemmal nNOSμ, which were linked to protection against the unloading phenotype, muscle fibre atrophy and partial fibre‐type shift from slow to fast twitch. The loss of nNOSμ from the sarcolemma appears crucial to Akt phosphorylation and is redox sensitive, although the mechanisms remain unresolved.

Mechanical unloading stimulates rapid changes in skeletal muscle morphology, characterized by atrophy of muscle fibre cross‐sectional area and a partial fibre‐type shift from slow to fast twitch. Recent studies revealed that oxidative stress contributes to activation of forkhead box O3a (FoxO3a), proteolytic signalling and unloading‐induced muscle atrophy via translocation of the μ‐splice variant of neuronal nitric oxide synthase (nNOSμ) and activation of FoxO3a. There is limited understanding of the role of reactive oxygen species in the Akt–mammalian target of rapamycin (mTOR) pathway signalling during unloading. We hypothesized that Eukarion‐134 (EUK‐134), a mimetic of the antioxidant enzymes superoxide dismutase and catalase, would protect Akt–mTOR signalling in the unloaded rat soleus. Male Fischer 344 rats were separated into the following three study groups: ambulatory control (n = 11); 7 days of hindlimb unloading + saline injections (HU, n = 11); or 7 days of HU + EUK‐134; (HU + EUK‐134, n = 9). EUK‐134 mitigated unloading‐induced dephosphorylation of Akt, as well as FoxO3a, in the soleus. Phosphorylation of mTOR in the EUK‐treated HU rats was not different from that in control animals. However, EUK‐134 did not significantly rescue p70S6K phosphorylation. EUK‐134 attenuated translocation of nNOSμ from the membrane to the cytosol, reduced nitration of tyrosine residues and suppressed upregulation of caveolin‐3 and dysferlin. EUK‐134 ameliorated HU‐induced remodelling, atrophy of muscle fibres and the 12% increase in type II myosin heavy chain‐positive fibres. Attenuation of the unloaded muscle phenotype was associated with decreased reactive oxygen species, as assessed by ethidium‐positive nuclei. We conclude that oxidative stress affects Akt–mTOR signalling in unloaded skeletal muscle. Direct linkage of abrogation of nNOSμ translocation with Akt–mTOR signalling during unloading is the subject of future investigation.
Foundry Data Analytics to Identify Critical Parameters Affecting Mechanical Properties of Investment Castings
Authors: Sata Amit , Ravi B.
Published: January 2018

Besides shape fidelity and internal soundness, mechanical properties have become critical acceptance criteria for investment cast parts. These properties are mainly driven by the chemical composition of cast alloy as well as process parameters. It is however, difficult to identify the most critical parameters and their specific values influencing the mechanical properties. This is achieved in the present work by employing foundry data analytic based on Bayesian inference to compute the values of posterior probability for each input parameter. This is demonstrated on real-life data collected from an industrial foundry. Controlling the identified parameters within the specific range of values resulted in improved mechanical properties. Unlike computer simulation, artificial neural networks and statistical methods explored by earlier researchers, the proposed approach is easy to implement in industry for controlling and optimizing the parameters to achieve the desired range of mechanical properties. The current work also shows the way forward for building similar systems for other casting and manufacturing processes.
Analysis of a Heat Exchanger for a Cogeneration Unit Using Computational Fluid Dynamics
Authors: Gášpár Roman , Souček Stanislav
Published: January 2018

A cogeneration unit is a device for the production of electricity and heat. Waste heat is used in the cogeneration (Combine Heat and Power or CHP) process. This process increases the efficiency of the whole cogeneration unit system. One of the most important parts of a cogeneration unit is the exhaust heat exchanger, where waste heat is recovered. The objective of this applied research is to examine the properties of a shell-and-tube heat exchanger for a CHP unit of up to 200 kW manufactured by TEDOM a.s. The computations presented in this article are the results of computations where the influence of the composition of flue gas entering the computation in comparison with measured quantities were examined. The article contains a comparison of the influence of the flue gas, represented by CO2, N2 and air as an ideal gas. The results include an analysis of the character of the flow in the heat exchanger, especially in the input volume of the flue gas, where, apart from the influence of the flue gas properties, the influence of the construction on the flue gas mass flow rate distribution into the tubes was also examined. The advantage of this extensive computation lies in the possibility of a detailed analysis of particular parts of the heat exchanger as well as the possibility of detecting potential construction imperfections, which could negatively influence heat transfer and hence the total efficiency of the heat exchanger and the CHP unit.
Improved Thermal Uniformity by Introducing Tree-Like Flowing Channels in a PEMFC Flow-Field Plate
Authors: Jia Yuxin , Zhu Rui , Sunden Bengt , Xie Gongnan
Published: January 2018

Thermal uniformity in the flow field plate of proton exchange membrane fuel cells (PEMFCs) is crucial for their power generating efficiency and reliability and therefore, has attracted much attention. The present numerical study is an attempt to optimize the flow channels via replacement of convectional zigzag continuous channels by tree-like bifurcated channels radially outwards. The numerical model is validated by experimental data available in the open literature. The effects of included angles and length ratios among the channels on thermal uniformity are analyzed based on detailed fluid flow characteristics. Results show that tree-like channels outperform conventional ones. It is found that tree-like flow channels can improve thermal uniformity of proton exchange membrane fuel cells. Within limits, with smaller angle between bifurcated flow channels and length ratio 2−1/3 between higher flow channel and lower flow channel, PEMFC can obtain the most uniform temperature distribution in Y shape tree-liked flow field.
Systematic Vibration Reliability Analysis of Random Parametered Gear Sets With Analytic and Multi-Crossing Monte Carlo Simulation Methods
Authors: Yupeng Ma , Jianguo Zhang , Jiwei Qiu
Published: January 2018

Vibration reliability analysis of gear sets considering various kinds of nonlinear random factors is essential for the safety of gear driven systems. In this paper, a rational definition of gear sets vibration reliability was presented at first by taking all kinds of vibration responses including displacement, velocity and acceleration into account uniformly by treating them as a series system with statistically independent components. According to the given definition, a systematic analyzing scheme for the vibration reliability of gear sets was proposed. Vibration reliability estimated via the analyzing scheme would make it conservative but more safely in design of gear driven systems. Subsequently, both analytic and numerical methods for gear sets vibration response reliability estimation were carried out based on the proposed analyzing scheme. The analytic method is suitable for the situations that the vibration responses of gears sets under random circumstances are stationary stochastic responses. While, the numerical method named Multi-crossing Monte Carlo Simulation (MULCMCS) can well solve the reliability estimating problems even when the vibration responses of gear sets are nonstationary stochastic processes. Finally, for illustration, a numerical case of analyzing the vibration response reliability of a single degree-of-freedom (DOF) gear set was given to demonstrate the effectiveness of the MULCMCS method.
A Comparison Between a Microturbine and a Scroll-Type Expander for a Small Scale ORC Energy Recovery System for Vehicular Application
Authors: Pantano Fabio , Capata Roberto
Published: January 2018

This paper deals with the comparison between an IFR microturbine and a scroll-type expander for the exploitation of an on board ORC energy recovery system. The sensible heat recovered from a common bus engine (typically 8000cc) feeds the energy recovery system that can generate sufficient extra power to sustain the air-conditioning system and part of the auxiliaries. The concept is suitable for all kind of thermally propelled vehicles, but the application considered here is specific for an urban bus. The ORC cycle performance is calculated by a Process Simulator (CAMEL Pro) and the results are discussed. A preliminary design of the considered expanders is proposed using ad-hoc made models implemented in MATLAB, the technical constraints inherent to each machine are listed and the expected performance is presented in order to perform the optimal choice of the expander.
Studies on Combustion Characteristics of Two Interacting Coal Particles at Different Separation Distance
Authors: He XianHui , Gu MingYan , Yan DaWei , Chen Xue , Yan Dan , Chu HuaQiang , Liu FengShan
Published: January 2018

To understand the interactions of coal particles on devolatilization, volatile burning, and char combustion, the combustion characteristics of two interacting equal-sized coal particles placed in the upstream and downstream configuration in a hot laminar flow are numerically investigated. A two-dimensional mathematical model was developed based on the wall surface reaction theory in the commercial software FLUENT. The numerical results show that the particle interaction has different effects on the coal ignition time and combustion characteristics of the upstream and downstream particles. The upstream coal particle undergoes a faster temperature rise, earlier coal devolatilization, and faster char burnout than the downstream one. With increasing the particle separation distance within a certain range, the temperature rise, coal devolatilization, and char combustion processes are further enhanced and weakened for the upstream particle and the downstream particle, respectively. There exists a critical particle separation distance beyond which the combustion processes of the two particles are similar to those of a single particle.
LTI Filtering- and Multiple Resonance-Based Signal Decomposition for Semi-Quantitative Fault Diagnosis of Rolling Bearings
Authors: Sun Hongjian , Huang Wentao , Jiang Yunchuan , Wang Weijie
Published: January 2018

Rolling bearing fault diagnosis is of great significance to ensuring the safe operation of rotating machinery, and vibration analysis based signal processing methods have become a mainstream of rolling bearing fault diagnosis technologies. Aiming at the separation of different signal components induced by rolling bearing composite defects, a novel signal decomposition based on linear time-invariant (LTI) filtering and multiple resonance is proposed in this paper, which can decompose the fault vibration signal with composite defects into high-, middle-, low-resonance components and the low-frequency component. The high- and middle-resonance components sparsely represent the damped responses induced by severe and slight defects, respectively. The low-resonance component represents transient component induced by some random interferences, and the low-frequency component contains the components of shaft rotation rate and harmonics caused by shaft bending or imbalance. Compared with conventional dual-Q-factor resonance-based signal sparse decomposition (RSSD), this method can not only detect the feature frequency, realize semi-quantitative analysis of defects’ amounts and severities, but also provide a monitor for shaft bending and imbalance. The effectiveness and practicability of this method has been validated by the experimental signal with dual defects on outer race, which explores a new way to apply RSSD to the diagnosis of rolling bearing composite defects.
Effect of Asperity Shape and Height on Thermal Contact Conductance of Metal-Metal Contacts: A Computational Study
Authors: Verma Navni N. , Mazumder Sandip
Published: January 2018

The thermal contact conductance (TCC) between two metallic rough surfaces is dictated both by the size and shape of the asperities on the surface. In this study, scale-resolved direct numerical simulation of thermal transport across the interface was conducted to isolate and quantify their effects. The mean roughness height (indicator of asperity size) and the mean absolute slope (indicator of asperity shape) of the asperities — two common surface topography descriptors — were treated as parameters, in addition to the contact pressure. Microscale models of the interface geometry were generated by statistically reconstructing the surface pairs from the aforementioned topography inputs, followed by generation of unstructured meshes that resolved all fine-scale features of the interface, including the air pockets. Steady state conjugate heat conduction computations were conducted, and the TCC values were extracted. The extracted TCC values were found to be in good agreement with experimental measurements. Examination of trends revealed the TCC to be a strong function of asperity size and a weak function of asperity shape. The extracted TCC data was finally reduced and curve-fitted by correlating it to two non-dimensional parameters: the number of contacts and the mean absolute slope. The accuracy of this correlation (curve-fit) was tested, and the TCC values predicted by it were found to be well within the statistical uncertainty of the raw DNS results. The curve-fit represents a simple, yet valuable tool for future researchers to estimate the TCC of metal-metal interfaces of any topography characterized by common topography descriptors.
Design of a Recumbent Vehicle With High Flexibility Elements
Authors: Ledesma Nieto Jose , Vidal Lesso Agustin , Ledesma Orozco Elias
Published: January 2018

In this work, a new model of a recumbent bike with the tensegrity method is developed, where all elements in tension are substituted for steel cables, to improve the weight of the vehicle and to absorb some of the impacts of the tires, since the cable works as a shock absorber. The aim of this study is to determine the structural strength of each of the elements of the recumbent vehicle and to establish dimensions and construction materials. The model is divided in 6 different elements, applying the equivalent loads and constrains to simulate the interaction with other elements, the user and the road, based on the HPVC 2017 rules [1]. Results show that in the analyzed sections, the maximum Von Mises stress obtained for all elements is 116 MPa, obtaining a minimum safety factor of 2.37 against tensile yield strength. Finally, through this work it is possible to apply the finite element method for failure analysis of each of the components of a recumbent vehicle and maximize its weight and resistance.
“To the Boards”: Team-Based Design for Student-Centered Learning
Authors: Gill David D. , Newcomer Jeffrey L.
Published: January 2018

Engineering design is a complex subject that is often a challenge for students to learn. Heuristic-based design, design that primarily utilizes “rules of thumb” or best practices, can be even more challenging for students to learn when they do not yet have the experience to choose between competing design guidelines. Faculty of Manufacturing Engineering at Western Washington University sought to improve the students’ learning in a senior-level, undergraduate course in Design of Tooling, a heuristic-based design discipline. The faculty worked to answer the question “How can team-based active learning approaches be effectively utilized for students learning a heuristic-based design topic?” In answering this question, the faculty developed and implemented a team-based, student-centered design activity called To the Boards. This activity, where small groups of students simultaneously develop tooling designs at whiteboards around the room, has improved the students’ retention of key concepts and helped students learn to analyze and apply competing design parameters. Performing the work on white boards encourages participation by all members of the group and enriches the design evaluation experience through a collaborative analysis of the many different design solutions developed by all the groups. Use of To the Boards, in conjunction with out-of-class reading, short lectures, and five large projects, has proven to be an effective tool for engaging students in learning, helping them to evaluate and apply competing design goals in the solution of complex engineering problems, and enabling collaborative design through communication of engineering concepts using sketches. Results of this activity have been measured through student performance and student feedback. Student performance on projects demonstrated the appropriate utilization of knowledge and skills learned in class with all students performing at satisfactory or exemplary levels when evaluated against ABET learning outcomes for design. Student feedback has been largely positive with the students recognizing the value of the knowledge and tooling design skills and also of the communication and teamwork skills that are acquired through the activity.
Modeling and Reconstruction of Multi-Fidelity Traumatic Head Injury due to Blunt Impact
Authors: Tan X. Gary , Bagchi Amit
Published: January 2018

Traumatic brain injury (TBI) is one of the most common injuries to service members in recent conflicts. Computational models can offer insights in understanding the underlying mechanism of brain injury, which lead to the crucial development of effective personal protective equipment designed to prevent or mitigate the TBI.

Historically many computational models were developed for the brain injury study. However, these models use relatively coarse mesh with a less detailed head anatomy. Many models consider the head only and thus cannot properly model the real scenario, i.e., accidental fall, blunt impact or blast loading. A whole-body finite element model can represent the real scenario but is very expensive to use.

By combining the high-fidelity human head model with an articulated human body model, we developed the computational multi-fidelity human models to investigate the blunt- and blast-related TBI efficiently. A high-fidelity computational head model was generated from the high resolution image data to accurately reproduce the complex musculoskeletal and tissue structure of the head. The fast-running articulated human body model is based on the multi-body dynamics and was used to reconstruct the accidental falls. By utilizing the kinematics and force and moment at the joint of the articulated human body model, we can realistically simulate the blunt impact and assess the brain injury using the high-fidelity head model.
Combat Helmet Pad Suspension Performance for Anthropomorphic Fit Designs, Brain Functional Areas and Injury Considerations
Authors: Tan X. Gary , Saunders Robert N. , Matic Peter
Published: January 2018

The effects of combat helmet pad suspension components on explosive device ballistic impact on the helmet shell are determined for four helmet geometric designs with and without pad suspension systems. Finite element analysis of a flat panel test article is used to generate back face deflection (BFD) data as a function of impact obliquity to be input into a computer aided design (CAD) software application. The CAD software is used to evaluate omni-directional ballistic impacts to the helmet using one dimensional equations of motion. The BFD and acceleration results of the CAD software analysis are used to determine a head injury criteria and abbreviated injury score (AIS). The AIS is related to ten focal and diffuse head injuries from trauma literature. The attenuation of helmet back face deflections and projectile deceleration for over-pad impacts compared to between-pad impacts translates into reduced injury predictions. The analysis quantifies these effects and helps to define the helmet trade space, facilitate prototyping, and support helmet design optimization.
Effect of Providing an Opportunity for Competition in Design Education
Authors: Iino Kenji , Nakao Masayuki
Published: January 2018

We have been offering conceptual design courses to graduate level mechanical engineering students. The courses are taught at three different graduate schools; Kyushu Institute of Technology, Sophia University, and The University of Tokyo. The mechanisms of course offering are different among these three schools, however, the underlying theme is the same. That is to identify a problem that the students want to solve and work in groups to come up with creative solutions. The students first go through sessions to sharpen their sense of feeling inconveniences. We then emphasize the importance of properly stating the functional requirement for their yet-to-build solution. Engineering students often struggle with this first stage. Once they set the goal, the course teaches brainstorming, Design Record Graph, and prototyping. Last year, we experimented with a final assignment of producing posters of their new products. The posters were collected and presented at an adult conference. The conference participants cast votes for their preferred posters. The top three winners received book cards to purchase books. This poster competition gave the students high incentives to produce good design proposals. The winning factor was not just technical supremacy but the votes were strongly affected by the solution presentation on the posters. It provided a good opportunity to teach engineering students that technology alone is not always the most important factor in winning businesses.
High Fidelity Model of a Ball Screw Drive for a Flight Control Servoactuator
Authors: Bertolino Antonio C. , Jacazio Giovanni , Mauro Stefano , Sorli Massimo
Published: January 2018

Over the past years, a trend toward “more electric” equipment has arisen including flight control systems, leading to a tendency to replace the electro-hydraulic actuators (EHSAs) with electro-mechanical actuators (EMAs), which have however a too high jamming probability for a primary flight control system. An innovative jam tolerant approach is to make the EMA “jam-predictive” by monitoring its health state using effective prognostic algorithms. The need for a high-fidelity model is then paramount. In this study, basing on a typical architecture of an EMA, a detailed analysis of the developed dynamic non-linear ball screw model is presented. The backlash, friction parameters, a model of the rolling/sliding behaviour of a ball with rolling friction are taken into account, contact stiffness and preload are introduced. A discussion is presented on the results of a sensitivity analysis on the efficiency of the mechanism with respect to the above mentioned characteristic parameters under different operating conditions. The model and the results of the sensitivity analysis can be used to better understand the physics within the actuator and the ensuing fault-to-failure mechanisms which are needed for developing more efficient prognostic algorithms.
Enhanced Production Process to Reduce Warranty
Authors: Michael-Shenouda Christina , Jawad Badih , Zinser Craig , Liu Liping , Abro Sabah
Published: January 2018

The present work aims at helping the automotive industry reduce warranty. First of all, an equation was developed to predict the warranty Incident per Thousand Vehicle (IPTV) ahead. A study was done to analyze the key points of quality that are related to Production Part Approval Process (PPAP): Design Failure Mode and Effect Analysis (DFMEA), First Time Quality (FTQ), complexity of the part, and Controlled Shipping (CS) to statically show the warranty reduction among different suppliers. Secondly, an Enhanced Production Process was implemented in March, 2016 in a supplier in Mexico. The Enhanced Audit Station ensures that the supplier is enforcing the PPAP requirements. The four most important components are: Touch Appearance Lighting and Color (TALC), Appearance Approval Report (AAR), Dimensional Checks, and Function Testing.

The enhanced process can provide more confidence in the life of a part in terms of producing quality parts and catching any defects that may result from a line move, or sub-tier change. If the supplier sets a process that is implemented at the End of Line (EOL), they will spend more time doing the proposed audit for their component. This will result in earlier identification of defects, parts that are out of tolerance, or parts that do not meet PPAP requirements. This process also might require spending extra money to run testing and can be included in the piece cost, but will save money by reducing warranty and by gaining repeat customers.
Analysis and Optimization of Determining Factors in Irreversible Electroporation for Large Ablation Zones Without Thermal Damage
Authors: Yang Yongji , Zhang Bing , Moser Michael , Zhang Edwin , Zhang Wenjun
Published: January 2018

The aim of this study was to analyze five factors that are responsible for the ablation volume and maximum temperature during the procedure of irreversible electroporation (IRE). The five factors used in this study were the pulse strength (U), the electrode diameter (B), the distance between the electrode and the center (D), the electrode length (L), and the number of electrodes (N). A validated finite element model of IRE was built to collect the data of the ablation volume and maximum temperature generated in a liver tissue. Twenty-five experiments were performed, in which the ablation volume and maximum temperature were taken as response variables. The five factors with ranges were analyzed to investigate their impacts on the ablation volume and maximum temperature, respectively, using analysis of variance (ANOVA). Response surface method (RSM) was used to optimize the five factors for the maximum ablation volume without thermal damage (the maximum temperature ≤ 50 °C). U, and L were found with significant impacts on the ablation volume (P < 0.001, and P = 0.009, respectively) while the same conclusion was not found for B, D and N (P = 0.886, P = 0.075 and P = 0.279, respectively). Furthermore, U, D, and N had the significant impacts on the maximum temperature with P < 0.001, P < 0.001, and P = 0.003, respectively while same conclusion was not found for B and L (P = 0.720 and P = 0.051, respectively). The maximum ablation volume of 2952.9960 mm3 without thermal damage can be obtained by using the following set of factors: U = 2362.2384 V, B = 1.4889 mm, D = 7 mm, L = 4.5659 mm, and N = 3. The study concludes that both B and N have insignificant impacts (P = 0.886, and P = 0.279, respectively) on the ablation volume; U has the most significant impact (P < 0.001) on the ablation volume; electrode configuration and pulse strength in IRE can be optimized for the maximum ablation volume without thermal damage using response surface method.
Methodological Support for the Selection of Simplified Equations of State for Modeling Technical Fluids
Authors: Schimanowski Alex , Seibel Arthur , Schlattmann Josef
Published: January 2018

Many technical applications require accurate predictions of the thermodynamical state of the process fluid, which can be estimated from mathematical equations of state (EoS). Though the existing EoS are sufficiently accurate in the wide operating ranges for various technical fluids, they differ in terms of the complexity, and thus in computation costs. Therefore, for modeling and simulation of large technical systems, preferably simple and sufficiently accurate EoS are desired. The proposed approach presents a methodological support for the selection of appropriate EoS not only considering its accuracy but also its complexity. Furthermode, a cryogenic application involving nitrogen is used to demonstrate the proposed approach.
Learning Experiences From an Industrially Sponsored Senior Design Capstone Program: A Student Perspective
Authors: Moreno Vito , Ferreira Meagan , Malicki Peter , Morris Seth , DePasquale John , Schier Logan , Smith Hollis
Published: January 2018

A key element of the Department of Mechanical Engineering Senior Design Program at the University of Connecticut is the industrial sponsorship of virtually all Capstone projects. This paper is a collaborative effort between the Program Manager and two of the current 2016–2017 student teams. The students discuss their initial reasons for selecting their projects and their experiences in working with a peer group in the planning and execution of a project. Learnings from their interaction with the industrial sponsor, achievement of the ABET objectives and the value that the project experience has provided in obtaining post-graduation employment. Opportunities and actions, based on this feedback, for continued development of the program to improve effectiveness are also identified.