bluuebunny/crossref_metadata_2025 huggingface dataset:
Tribological and physical properties of PTFE-NBR self-lubricating composites under water lubrication
Authors: Feng Wei , Yin Lei , Han Yanfeng , Wang Jiaxu , Xiao Ke , Li Junyang
Published: August 2020

Purpose

This paper aims to explore the possibility of converting the nitrile butadiene rubber (NBR) water-lubricated bearing material into a self-lubricating bearing material by the action of polytetrafluoroethylene (PTFE) particles and water lubrication.

Design/methodology/approach

A group of experimental studies was carried out on a ring-on-block friction test. The physical properties, tribological properties and interface structure of PTFE-NBR self-lubricating composites filled with different percentages of PTFE particles were investigated.

Findings

The experimental results indicated that the reduction in friction and wear is a result of the formation of the lubricating film on the surface of the composites. The lubricating film was formed of a large amount of PTFE particles continuously supplied under water lubrication conditions and the PTFE particles here can greatly enhance the load capacity and lubrication performance.

Originality/value

In this study, the tribological properties of PTFE particles added to the NBR water-lubricated bearing materials under water lubrication were investigated experimentally, and the research was carried out by a ring-on-block friction test. It is believed that this study can provide some guidance for the application of PTFE-NBR self-lubricating.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2020-0187/
Employee proactivity, work engagement, job resources and service recovery performance: a study of structural linkages
Authors: Zahoor Adil
Published: August 2020

Purpose

This study explores the driver influence of employee proactive personality on service recovery performance with work engagement as mediator. The moderating role of job resources (social support, supervisory coaching and performance feedback) is also examined in the proactivity-performance linkage to analyze the interaction effect of employee proactivity and job resources on recovery performance.

Design/methodology/approach

Primary data pertaining to the constructs under investigation were collected using a structured questionnaire from 432 dyads of employees from four companies operating in the Indian retail banking sector. Each dyad comprised of one frontline employee and her peer (colleague). Responses to work engagement and job resources were self-reported by frontline staff, as peer ratings were solicited for frontline employees' proactivity and recovery performance.

Findings

Empirical findings suggest that frontline employees' proactive personality significantly ameliorates their work engagement which in turn exerts a positive driver effect on their service recovery performance. In the case of less proactive employees (those with a proactivity score of less than mean value), service recovery performance is boosted when they receive constant feedback on their recovery performance. The results, however, did not provide significant evidence with regard to the moderating role of social support and supervisory coaching.

Originality/value

This study is one of the maiden attempts to relate employee proactive personality with service recovery performance. Since the research relating personality with recovery performance is largely underexplored yet fundamentally important, this study expands the available literature by examining as to what type of employee is more likely to deliver superior service recovery performance with little organizational support.
SECURE – a new business model framework for measuring start-up performance
Authors: Arshi Tahseen Anwer , Rao Venkoba , Islam Sardar , Morande Swapnil
Published: August 2020

Purpose

Existing business model frameworks show weak conceptual unification, a paucity of measurement focus and limitations when applied in emerging economies. The study proposes a new business model framework – “Start-up Evaluation Calculus Using Research Evidence” (SECURE). The purpose of this study is to allow the measurement of the impact of business model design on start-up performance in emerging economies.

Design/methodology/approach

Data collected from 713 entrepreneurs in select cities of India, Oman and the United Arab Emirates is analyzed through structural equation modeling. The study uses measurement and structural models to examine the validity of measures and additionally tests the five hypothesized relationships proposed in the study.

Findings

The SECURE’s components comprising desirability, marketability, feasibility, scalability and viability showed validity and reliability. They synergistically demonstrated a statistically significant effect on a mix of financial and non-financial start-up performance outcomes. An alternative structural relationship that examined the impact of SECURE on only financial performance outcomes showed a weaker model fit. The findings indicate that a business model framework is useful when its ex ante measures show a positive causal effect on the desired performance outcomes.

Practical implications

The scores obtained by the SECURE framework serve as an evaluative tool that informs entrepreneurs and start-ups on the readiness of their proposed, incubated or existing start-ups.

Originality/value

Replacing subjective judgments with objective assessment criteria, SECURE is one of the first quantitative and performance-driven business model frameworks that contain measures from all functional domains of a start-up business. Start-ups can evaluate their business models against the SECURE model’s research-driven quantitative criteria and assess their impact on start-up performance.
Identifying the drivers of resistance to corporate social responsibility: the case of Lebanese SMEs
Authors: Elhajjar Samer , Ouaida Fadila
Published: August 2020

Purpose

Although many Lebanese small and medium-sized enterprises (SMEs) express concern about social and environmental issues and report intentions to engage in pro-environmental activities, other enterprises still resist to embed a culture of social responsibility. After the analysis of major scholarship in the field, this paper defines corporate social responsibility (CSR) culture and provides an overview of the contemporary debate on it.

Design/methodology/approach

Through exploratory study, this paper identifies reasons why Lebanese SMEs do not embody CSR into their culture. The empirical data were gathered through 18 in-depth interviews with questions based on the main research questions.

Findings

Findings reveal that resistance to change is one of the main drivers of resistance to CSR. Collective and organizational culture can source this resistance to CSR.

Originality/value

This paper contributes to filling the gap in the literature in relation to CSR in small-medium firms and in particular Lebanese SMEs.
Firm location and systematic risk: the real estate channel
Authors: Gao Xiang , Topuz John
Published: August 2020

Purpose

This paper aims to investigate whether the cyclicality of local real estate prices affects the systematic risk of local firms using a geography-based measure of land availability as a quasi-exogenous proxy for real estate price cyclicality.

Design/methodology/approach

This paper uses the geography-based land availability measure as a proxy for the procyclicality of real estate prices and the location of a firm’s headquarters as a proxy for the location of its real estate assets. Four-factor asset pricing model (market, size, value and momentum factors) is used to examine whether firms headquartered in more land-constrained metropolitan statistical areas have higher systematic risks.

Findings

The results show that real estate prices are more procyclical in areas with lower land availability and firms headquartered in these areas have higher systematic risk. This effect is more pronounced for firms with higher real estate holdings as a ratio of their tangible assets. Moreover, there are no abnormal returns to trading strategies based on land availability, consistent with stock market betas reflecting this local real estate factor.

Research limitations/implications

This paper contributes to the literature on local asset pricing factors, the collateral role of firms’ real estate holdings and the co-movement of security prices of geographically close firms.

Practical implications

This paper has important managerial implications by showing that, when firms decide on the location of their buildings (e.g. headquarters building, manufacturing plant and retail outlet), the location’s influence on systematic risk should be part of the decision-making process.

Originality/value

This paper is among the first to use a geography-based measure of land availability to study whether the procyclicality of local real estate prices influences firm risk independent of the procyclicality of the local economy. Thus, both the portfolio formed and firm-level analyses provide a more direct evidence of the positive relation between the procyclicality of local real estate prices and firm risk.
Sperm morphology: What implications on the assisted reproductive outcomes?
Authors: Cito Gianmartin , Picone Rita , Fucci Rossella , Giachini Claudia , Micelli Elisabetta , Cocci Andrea , Falcone Patrizia , Minervini Andrea , Carini Marco , Natali Alessandro , Coccia Maria E.
Published: August 2020

Objective

To evaluate the impact of sperm morphology (SM) on laboratory and pregnancy outcomes in conventional intracytoplasmic sperm injection (c‐ICSI) cycles, using the egg donation model to minimize female confounding variables.

Materials and methods

We retrospectively collected data of oocyte donation cycles from October 2016 to February 2020. Median seminal parameters, total (1‐2‐3PN) fertilization rate (FR), 2PN FR, cleavage rate (CR), implantation rate (IR), pregnancy rate (PR), miscarriage rate (MR), and live birth rate (LBR) were collected. The study population was divided into three groups: Group 1 with SM < 4%, Group 2 with SM between 4% and 6%, and Group 3 with SM > 6%.

Results

Of 741 fresh ICSI cycles and 4507 warmed oocytes were included. Male age was 46.0 (31.0‐72.0) years, and recipients’ age was 44.0 (29.0‐54.0) years. Normal SM was 5.0% (1.0%‐15.0%). Male age was negatively correlated with normal SM (P = .002; Rho −0.113). Oocyte survival rate was 83.3% (16.7%‐100.0%). Total FR was 75.0% (11.1%‐100.0%), 2PN FR was 66.7% (11.1%‐100.0%) %, and CR was 100% (0.0%‐100%). Comparing samples with SM > 6% and those with SM < 4%, 2PN FR was significantly higher in the first group (P = .04). No significant associations were found among groups in terms of CR. IR was 27.7%, resulting significantly higher when normal SM was > 6% (P < .01). Clinical PR was 36.0%, MR was 23.9%, and LBR was 25.9%. PR and LBR were significantly higher in samples with normal SM > 6%, compared to other groups (P = .02 and P < .01, respectively).

Conclusions

Although c‐ICSI technique allows the embryologist to select the best quality spermatozoa, male factor plays a key role in achieving successful assisted reproductive outcomes. Normal SM has been shown to have implications not only for laboratory outcomes, in terms of fertilization, but also for clinical findings, as regards implantation, pregnancy, and live birth.
Influence of dietary crude protein content on fattening performance and nitrogen excretion of Holstein steers
Authors: Kamiya Mitsuru , Yamada Tomoya , Higuchi Mikito
Published: August 2020

The objective was to investigate the influence of crude protein (CP) content in a fattening diet on feed intake, body weight gain, nitrogen excretion, and carcass traits in Holstein steers. Steers (initial body weight 241 ± 26 kg) consumed feed with the following CP content: (a) 17.7% during the early period (from 7 to 10 months of age) and 13.9% during the late period (from 11 to 18 months of age) (HIGH, n = 3), and (b) 16.2% during the early period and 12.2% during the late period (LOW, n = 4). The CP intake was lower in the LOW than the HIGH group. Urinary and total nitrogen excretion in the late period tended to be lower (p < .10) in the LOW than the HIGH group. However, growth performance and carcass traits were not affected by dietary CP content. Free histidine and total amino acid contents in the longissimus thoracis muscle tended to be higher (p < .10) in the HIGH than the LOW group, however, the CP contents were not affected by dietary CP content. The results of this experiment suggest that decreasing dietary CP to 16% (early period) or 12% (late period) of dry matter would reduce nitrogen excretion from Holstein fattening farms without affecting productivity.
Motivations for the use and consumption of wildlife products
Authors: Thomas‐Walters Laura , Hinsley Amy , Bergin Daniel , Burgess Gayle , Doughty Hunter , Eppel Sara , MacFarlane Douglas , Meijer Wander , Lee Tien Ming , Phelps Jacob , Smith Robert J. , Wan Anita K. Y. , Veríssimo Diogo
Published: August 2020

The dominant approach to combating the illegal wildlife trade has traditionally been to restrict the supply of wildlife products. Yet conservationists increasingly recognize the importance of implementing demand‐side interventions that target the end consumers in the trade chain. Their aim is to curb the consumption of wildlife or shift consumption to more sustainable alternatives. However, there are still considerable knowledge gaps in understanding of the diversity of consumer motivations in the context of illegal wildlife trade, which includes hundreds of thousands of species, different uses, and diverse contexts. Based on consultation with multiple experts from a diversity of backgrounds, nationalities, and focal taxa, we developed a typology of common motivations held by wildlife consumers that can be used to inform conservation interventions. We identified 5 main motivational categories for wildlife use: experiential, social, functional, financial, and spiritual, each containing subcategories. This framework is intended to facilitate the segmentation of consumers based on psychographics and allow the tailoring of interventions—whether behavior change campaigns, enforcement efforts, or incentive programs—to the specific context in which they will be used. Underlining the importance of consumer research and collaborating with local actors is an important step toward promoting a more systematic approach to the design of demand reduction interventions.
Evaluating surrogates of genetic diversity for conservation planning
Authors: Hanson Jeffrey O. , Veríssimo Ana , Velo‐Antón Guillermo , Marques Adam , Camacho‐Sanchez Miguel , Martínez‐Solano Íñigo , Gonçalves Helena , Sequeira Fernando , Possingham Hugh P. , Carvalho Silvia B.
Published: August 2020

Protected‐area systems should conserve intraspecific genetic diversity. Because genetic data require resources to obtain, several approaches have been proposed for generating plans for protected‐area systems (prioritizations) when genetic data are not available. Yet such surrogate‐based approaches remain poorly tested. We evaluated the effectiveness of potential surrogate‐based approaches based on microsatellite genetic data collected across the Iberian Peninsula for 7 amphibian and 3 reptilian species. Long‐term environmental suitability did not effectively represent sites containing high genetic diversity (allelic richness). Prioritizations based on long‐term environmental suitability had similar performance to random prioritizations. Geographic distances and resistance distances based on contemporary environmental suitability were not always effective surrogates for identification of combinations of sites that contain individuals with different genetic compositions. Our results demonstrate that population genetic data based on commonly used neutral markers can inform prioritizations, and we could not find an adequate substitute. Conservation planners need to weigh the potential benefits of genetic data against their acquisition costs.
The effect of a low glycaemic index diet on reducing day‐long glycaemia in healthy young adults: A randomized crossover trial
Authors: Hon Hannah Wing Han , Wong Tommy Hon Ting , Tse Iris Mei Ying , Louie Jimmy Chun Yu
Published: August 2020

Aim

To compare the effect of a low glycaemic index (LGI) diet on reducing day‐long glycaemia with a macronutrient‐matched high glycaemic index (HGI) diet, using customized meal delivery to ensure compliance.

Materials and Methods

We conducted a single‐blinded, randomized crossover trial in 14 healthy adults (57% female) with a mean ± SD age of 21.6 ± 1.7 years. A flash glucose monitoring sensor was installed on the subjects on day 1 to capture the interstitial glucose level every 15 minutes for 14 days. Subjects were randomized to receive an LGI (dietary GI = 40) or HGI (dietary GI = 60) diet (three meals and two snacks) from day 2 for 5 consecutive days, followed by a 2‐day washout, then switched to the alternative diet for another 5 days. A paired t‐test was used to test the differences in the incremental area under the curve (iAUC) of glucose, postprandial glucose (PPG) concentration and maximum postprandial glucose rise (MPGR) between the LGI and HGI periods.

Results

Subjects had lower iAUC for average day‐long glycaemia during the LGI intervention period compared with the HGI period (mean ± SD, 865 ± 297 vs. 1024 ± 267 mmol x min/L; P = .047). PPG for breakfast and snack 2, and MPGR for breakfast, snack 2 and dinner, were lower in the LGI period.

Conclusions

In young healthy adults, following an LGI diet resulted in lower average day‐long glycaemia compared with a macronutrient‐matched HGI diet. Our results support the use of LGI diets to reduce the risk of developing glucose intolerance.
Reversal of economic fortunes: Institutions and the changing ascendancy of Barcelona and Madrid as economic hubs
Authors: Rodríguez‐Pose Andrés , Hardy Daniel
Published: August 2020

This paper looks at the divergent economic trajectories of Barcelona and Madrid since Spain's transition to democracy. It highlights how Barcelona, the city that was better positioned four decades ago to emerge as the main Spanish economic hub, has lost out to Madrid. We argue that the contrasting trajectories of the two cities have less to do with the pull of Madrid as the capital of Spain, with the development of new infrastructure in the country, or with agglomeration economies, and more with institutional factors. A growing societal divide in Barcelona along economic, social, and identity lines has led to a greater breakdown of trust and to the development of strong groups with limited capacity to bridge with one another than in Madrid. This has entailed the emergence of negative externalities that have limited the economic potential for growth in Barcelona and facilitated the rise of Madrid as the main economic hub within Spain.
Glyburide Use in Older Adults: Pharmacy Claims Data Analysis of a Regional Healthcare Organization
Authors: Herzik Kristen A. , Barnett Mitchell J. , Thanh Danielle M. , Doroudgar Shadi , Ip Eric J.
Published: August 2020

BACKGROUND/OBJECTIVES

Glyburide was added to the 2012 American Geriatrics Society (AGS) Beers Criteria® due to the risk of hypoglycemic events in older adults. The objective of this study was to evaluate trends of glyburide use in persons aged 65 and older with diabetes mellitus, type II, before, during, and after the 2012 AGS Beers Criteria® Update.

DESIGN

Multicenter retrospective cohort study comparing pharmacy claims data from four Sharp Rees‐Stealy clinic regions over 5 years (2010–2015).

SETTING

Pharmacy claims database.

PARTICIPANTS

A total of 3,005 patients with diabetes mellitus, type II, aged 65 and older.

MEASUREMENTS

Prescription fill history of the sulfonylureas glyburide, glipizide, and glimepiride were collected along with comorbidity (Elixhauser) and demographic information. Odds of glyburide prescribing were stratified by year, clinic region, and by prescriber type.

RESULTS

Glyburide use decreased across each study year (35.8%, 27.7%, and 4.2% in 2011, 2013, and 2015, respectively; P < .01). Adjusted odds of glyburide use indicated that regions A and D were 24% (P = .045) and 11% (P < .01) less likely to prescribe glyburide in 2011, regions A and D were 37% (P < .01) and 8% (P = .03) less likely to prescribe glyburide in 2013, respective to the overall average, whereas region B was 41% (P = .04) more likely. No significant regional site variations remained in 2015. Internists were 47% more likely to prescribe glyburide than family medicine providers in 2013; P < .01), but not in any other study years.

CONCLUSION

Rates of glyburide use decreased after release of the 2012 AGS Beers Criteria® demonstrating successful adoption of evidence‐based medicine at a large multiregional site. However, regional differences may affect timing of implementation. Education, system‐level initiatives, and strong professional support may help enhance more uniform adoption. J Am Geriatr Soc 68:2354–2358, 2020.
A Public Health Ethics Analysis of the Criminalization of Direct Entry Midwifery
Authors: DeJoy Sharon Bernecki
Published: August 2020

Multiple types of midwives practice in the United States, but regulation of midwifery practice varies by state. In some states, direct entry midwifery practice is unregulated or criminalized. Because regulations are the most burdensome of the public health interventions, they require the most stringent ethical critique. This article uses the most recent Public Health Code of Ethics to analyze the ethics of regulations that criminalize direct entry midwifery practice. The Code establishes 8 criteria for ethical actions: (1) permissibility, (2) respect, (3) reciprocity, (4) effectiveness, (5) responsible use of scarce resources, (6) proportionality, (7) accountability and transparency, and (8) public participation. Laws that criminalize direct entry midwifery practice violate all of these criteria and therefore cannot be considered an ethical approach to the state's duty to safeguard public health. The remedy for this problem is for all states to license and regulate all types of midwives that meet international standards of education and training.
Endometrial cancer patients have high affinity antibodies for estrogen metabolite–receptor aggregate: A potential biomarker for EC
Authors: Khan Wahid Ali , Alsamghan Awad Saeed , Khan Mohd Wajid Ali
Published: August 2020

Aim

Elevated levels of 16α‐hydroxyestrone (16α‐OHE1) have been described in endometrial cancer (EC) and estrogen receptors (ER) expressed in endometrial tissue, but research on their combined role is lacking. We aimed to investigate the affinity and binding specificity of EC antibodies against the 16α‐OHE1‐ERα aggregate in the serum of EC patients. Specificities of EC antibodies were also evaluated according to various clinical characteristics found in these cancer patients.

Methods

The binding specificity and affinity of EC antibodies against 16α‐OHE1‐ERα in the serum of 120 EC patients were evaluated by direct binding and competition ELISA and quantitative precipitation titration. Binding of EC antibodies was also determined according to various clinical characteristics in EC patients through competition ELISA.

Results

Antibodies from EC patients demonstrated high recognition of 16α‐OHE1‐ERα compared to ERα (P < 0.05) or 16α‐OHE1 (P < 0.001). The relative affinity of EC IgG was 1.49 × 10−7 M, 1.34 × 10−6 M and 1.13 × 10−6 M for 16α‐OHE1‐ERα, ERα and 16α‐OHE1, respectively. Several factors, such as obesity, postmenopausal status, use of hormonal therapy, ER and progesterone receptor (PR) status, low 2‐OHE1/16α‐OHE1 ratio, chemotherapy and hypertension, augment the production of antibodies against 16α‐OHE1‐ERα in EC patients.

Conclusion

16α‐OHE1‐ERα is a high‐affinity antigen for EC antibodies in the serum of EC patients and might function as a biomarker for this disease. Furthermore, several factors enhanced the production of antibodies against 16α‐OHE1‐ERα in the sera of these EC patients.
Weak Data: The Social Biography of a Measurement Instrument and How It Failed to Ensure Accountability in Home Care
Authors: Hoeyer Klaus , Bødker Malene
Published: August 2020

Contemporary health and social care is saturated by processes of datafication. In many cases, these processes are nested within an ostensibly simple logic of accountability: Define a politically and morally desirable goal, then measure the level of achievement. This logic has come to permeate public health initiatives globally and today it operates in most health care systems in various ways. We explore here a particular instantiation of the logic associated with the introduction of a measurement instrument used in Danish home care. Building on ethnographic fieldwork, interviews, and analysis of policy documents, we show how the instigated processes of datafication—despite hopeful political claims—erode care levels and disempower older people. We believe that these findings can be of relevance for other settings that subscribe to the same accountability logic and to similar forms of measurement instruments.
Factors associated with anaemia among women of reproductive age in Ethiopia: Multilevel ordinal logistic regression analysis
Authors: Tirore Lire Lemma , Mulugeta Afework , Belachew Abate Bekele , Gebrehaweria Menaseb , Sahilemichael Abraham , Erkalo Desta , Atsbha Rigeat
Published: August 2020

Anaemia has prevailed as a mild to severe public health problem in Ethiopian women of reproductive age. Many studies carried out on anaemia have been limited to subnational assessments and subgroups of women. The effects of potential factors thought to affect anaemia and severity levels of anaemia have not been well considered. Therefore, this study identifies individual, household and community level factors associated with anaemia among women of reproductive age in Ethiopia applying multilevel ordinal logistic regression models. Proportional odds assumption was tested by likelihood ratio test. About 35.6% of the variation on anaemia was due to between household and community level differences. Pregnancy (adjusted odds ratio [AOR] = 2.30, 95% confidence interval [CI]: 1.82, 2.91), HIV (AOR = 2.40, 95% CI: 1.76, 3.25), giving birth once (AOR = 1.2, 95% CI: 1.05, 1.40), giving birth more than once (AOR = 1.4, 95% CI: 1.19, 1.71), living with five or more family members (AOR = 1.24, 95% CI: 1.05, 1.47), living in poorest households (AOR = 1.34, 95% CI: 1.2, 1.61) and rural area (AOR = 1.57, 95% CI: 1.28, 1.92) were associated with greater odds of more severe anaemia compared with their respective counter parts. Secondary and above education (AOR = 0.83, 95% CI: 0.70, 0.97) and use of pills, implants or injectable (AOR = 0.67, 95% CI: 0.59, 0.77) were associated with lower odds of more severe anaemia. Anaemia prevention and control programmes need to be strengthened for women living with HIV/AIDS and during pregnancy. Household poverty reduction and social protection services need to be strengthened and integrated in anaemia prevention and management activities in women.
Anesthetic implications of a pediatric patient with stiff skin syndrome: A case report
Authors: Kiss Edgar E. , Alex Gijo , Chandran Neethu , Olomu Patrick
Published: August 2020

Stiff skin syndrome is a rare genetic disorder that is present in infancy or early childhood. It is characterized by hard, inflexible skin and limited joint mobility making anesthetic management of these patients challenging. Their limited neck flexibility and chest wall rigidity make intubation and mask ventilation difficult. Intraoperative positioning can be challenging due to joint contractures and potential entrapment peripheral neuropathy. Even though peripheral intravenous access can be relatively easy, central venous cannulation may be problematic due to the hard skin overlying the entry sites. Our case report details the anesthetic management and considerations of a pediatric patient with stiff skin syndrome.
Bayesian Econometric Modelling of Observational Data for Cost-effectiveness Analysis: Establishing the Value of Negative Pressure Wound Therapy in the Healing of Open Surgical Wounds
Authors: Saramago Pedro , Claxton Karl , Welton Nicky J. , Soares Marta
Published: August 2020

In the absence of evidence from randomized controlled trials on the relative effectiveness of treatments, cost-effectiveness analyses increasingly use observational data instead. Treatment assignment is not, however, randomized, and naive estimates of the treatment effect may be biased. To deal with this bias, one may need to adjust for observed and unobserved confounders. In this work we explore and discuss the challenges of these adjustment strategies within a case-study of negative pressure wound therapy (NPWT) for the treatment of surgical wounds healing by secondary intention. We could not demonstrate that existing uncontrolled confounding affects NPWT effectiveness, and thus there was no evidence that NPWT was cost effective compared with standard dressings for the treatment of surgical wounds healing by secondary intention.
Inflation-Induced Twist in Geometrically Incompatible Isotropic Tubes
Authors: Emuna Nir , Cohen Noy
Published: August 2020

The fundamental twist motion in tubes is commonly generated by torque. However, twist can also be indirectly induced by mechanical loadings (inflation/extension), growth and remodeling processes, and environmental conditions. This unusual coupling commonly originates from material anisotropy. In this study, we propose a configuration of isotropic bilayer tubes that twists upon inflation. This mechanism is based on twist incompatibility: two tubes are axially twisted in opposing directions and glued to form a bilayer tube. The residual stress that develops gives rise to deformation-induced anisotropy, which enables twist under inflation. To demonstrate the induced-twist response, we employ the neo-Hookean and the Gent models. We derive closed-form expressions for the twist angle as a function of the pressure in neo-Hookean bilayer tubes and show that a terminal angle exists in the limiting pressure. Numerical studies of bilayer Gent tubes are carried out and reveal that the lock-up effect governs the terminal twist angle. Interestingly, we find that in bilayer Gent tubes, the twist direction and handedness can be reversed upon inflation. These counter-intuitive effects, known as inversion and perversion, respectively, stem from the load-dependent variations in the ratio between the torsional stiffness of the two layers. We provide criteria that allow to program the induced twist response of bilayer tubes through the design of the properties of the two layers. This approach may be of value in the design of soft robots, artificial muscles, and soft actuators.
Design of a Portable Venomanometer System for Episcleral Venous Pressure Measurement
Authors: Yap Tze Yeen , Nelson Carl A. , Ghate Deepta , Gulati Vikas , Fan Shan , Kedar Sachin , Gagrani Meghal , Hahn Adam , Minden Blaine , Moorhous Luke , Fowler Zachary , Khazanchi Deepak
Published: August 2020

Traumatic brain injury (TBI) has been considered a precarious health issue especially within the military population. Research has shown that early treatment of TBI could reduce possible neurocognitive injury. However, the nature of military triage has created challenges for early TBI detection. Intracranial pressure (ICP), which is used as a biomarker of outcomes in TBI, is not only expensive to measure but is also invasive and requires specialized surgical and procedural skills. Episcleral venous pressure (EVP) was proven to be a good alternative biomarker to ICP. However, the current technology in measuring EVP is not portable, and requires a skilled operator with a slit-lamp for testing. Moreover, the measurement is highly subjective and depends on the operator’s skill and technique. Therefore, there is a critical need for alternative technology for non-clinical TBI diagnosis. In this paper, we present an improved venomanometer design for measuring EVP in the field.
Cable-Driven 3D Steerable Surgical Needle for Needle-Based Procedures
Authors: Khashei Varnamkhasti Zahra , Konh Bardia
Published: August 2020

Surgical needles have been used in many percutaneous needle-based procedures such as biopsy and brachytherapy in recent years. The needle-based procedures have replaced open surgeries to perform the tasks with minimal invasiveness to the tissue. Precise needle insertion at target position in cancer diagnostic and therapeutic procedures governs the success of such procedures. This work presents a cable-driven 3D steerable needle for improved guidance inside the tissue towards the target. The needle is manipulated by pulling cable tendons via programmed stepper motors. Feasibility tests in air and in a tissue-mimicking phantom showed an average 3D needle deflection of 11.06 and 10.49 degrees, respectively. The controlled (on demand) 3D deflection of this needle is expected to assist surgeons in trajectory tracking and targeting accuracies. This amount of deflection, when combined with needle steering systems with path planning, can potentially realize higher deflections with small radius of curvature.
Introducing a Cost-Effective Radiopaque Scale Design for Intra-Operative Use
Authors: Dey Roopam , Beukes Giancarlo , Nair Gokul , Sivarasu Sudesh
Published: August 2020

Radiopaque scales have numerous uses in the field of surgery, especially orthopaedic surgery. Scales of this nature can be used to guide surgeons by taking intra-operative measurements, pinpoint insertion points on bones and detect locations of deformations and tumours inside the body. Despite this, these scales are not used widely enough because of its high cost and that there are no widely acceptable ways of developing them from off the shelf materials. This paper details the method of inventing a novel low-cost radiopaque scale using off the shelf materials such as Barium Sulfate and Iodinated Contrast Agent (ICA). The radiopaque scale was manufactured using Perspex® and was filled with the contrast agents. The scales were then scanned using low-dose X-ray machines. The scale filled with Barium was found to be provide a better contrast image suggesting that the Barium to be a better high-contrast agent when compared to iodine and is recommended for use.
Numerical Study on the Delay Effect of Air Brake Mass Flow on Train Coupler Forces
Authors: Aboubakr Ahmed K. , Shabana Ahmed A.
Published: August 2020

In existing freight-train braking systems, braking is applied on individual cars sequentially at the speed of the air pressure. In the case of long trains that consist of hundreds of rail cars, there is a time delay that results in large and impulsive compressive and tensile coupler forces. These coupler forces compromise the train safe operation and stability, make train handling difficult, cause track damage, raise significantly the maintenance cost, and increase the stopping distances which can lead to serious accidents. The objective of this investigation is to investigate the effect of the brake-delay time on the train longitudinal dynamics (LTD) coupler forces by integrating for the first time detailed three-dimensional coupler and air-brake force models. A spatial non-linear coupler model that takes into account the geometric nonlinearities is employed in order to allow for capturing arbitrary three-dimensional rail-car motion and coupler kinematic degrees of freedom that cannot be captured using existing simpler models. This coupler model is integrated with a detailed air brake model that consists of the locomotive automatic brake valve, air brake pipe, and car control unit (CCU) in order to evaluate conventional air brake force models that account for the air-flow effect in long train pipes as well as the effect of leakage and branch pipe flows. The coupling between the air brake, locomotive automatic brake valve, car control units, and train equations is established and used in the nonlinear LTD simulations, which are performed using the computer software ATTIF (Analysis of Train/Track Interaction Forces). Different LTD braking scenarios are considered and the effect of brake signal time delay on the coupler forces is examined. The results obtained in this study demonstrate the importance of applying all brake forces simultaneously in order to ensure train stability and safety.
Creation of 25kV AC Neutral Section in Bored/Round Tunnel of Delhi MRTS
Authors: Pande Om Hari , Tewari Ashok , Kumar Sanjeev , Singh Rajesh Kumar
Published: August 2020

Delhi metro uses 25kV single phase AC traction electric supply to power trains which is usually supplied through a continuous conductor running along the track such as overhead lines. Traction power is supplied from Traction sub stations which can cater a smaller portion of the line. Hence, AC traction system for one line comprises of different sections of suitable length being fed by different sub-stations. The electric power is generated in three phases with each having a phase shift of 120°, there is a possibility of two different traction sections being fed by different phases of power supply. In such condition, to avoid the risk of supply mixing of different phases, there is need to keep these sections isolated from each other. Therefore, a specific arrangement of conductor is done and a neutral section is created, which is preferably an earthed section.

A significant portion of metro lines runs underground therefore the neutral section in underground tunnels is provided in a box tunnel constructed through cut and cover method to maintain the required clearances for separation of different phase power supply. The cut and cover method involves temporary acquisition of land, massive excavation followed by a durable covering to support the overhead construction and subsequent restoration of excavated area which takes around 6–8 months in construction. Moreover, neutral section is to be located at a minimum distance of 250 meters from platform having tangent track, zero gradient, no stop signals.

Accordingly, there is a need of developing improved and cost-effective technology for providing neutral sections in the AC traction system in underground to reduce the time taken for construction and abolish the present practice of constructing a cut & cover tunnel between two stations.

The present invention provides a time and space saving method of incorporating neutral sections in the 25kV AC traction system within the round/bored tunnel by creating a niche in the soffit of tunnel which also ensures all the safety clearances required for making effective neutral sections.

The tunnel with circular cross section is bored using tunnel boring machines. The bored tunnel is approximately 5.6m to 5.8m in diameter to house the track, metro train, overhead equipments for electrification. A neutral section is to be housed in the niche created in the ceiling of the round/bored tunnel during the boring process itself. The time spent in boring tunnel utilizing boring machines is considerably less than the time spent in cut and cover method of construction.

This Paper present in detail the design concept prepared by DMRC for Creation of 25 KV AC neutral section in Bored/Round Tunnel of Propose Phase-IV of Delhi MRTS. DMRC has also filed a patent for the innovation with Indian Patent Authority.
Rapid Charging Energy Storage System for a Hybrid Freight Locomotive
Authors: Spiryagin Maksym , Wolfs Peter , Wu Qing , Bosomworth Chris , Cole Colin , McSweeney Tim
Published: August 2020

This paper examines whether rapid charging technology could enable implementation in a hybrid freight locomotive design and how it might benefit the existing freight train operation scenarios.

In the study, a hybrid locomotive design with rapid charging technology has been proposed and implemented with the application of advanced simulation techniques used in recent locomotive/train/track damage studies. The detailed hybrid locomotive model includes multibody subsystems for the locomotive mechanical system and a traction power system including a full battery pack model with an ESS (Energy Storage System) control algorithm implemented in the Matlab/Simulink software package.

For the train performance study, the traction effort and dynamic braking characteristics obtained from the hybrid locomotive model have been incorporated into an in-house train dynamics package for the analysis of locomotive performance, infrastructure requirements and economics under a realistic operational study.
Simulation of Heavy Haul Train Energy Consumption With Locomotive Adhesion Model
Authors: Wu Qing , Spiryagin Maksym , Cole Colin
Published: August 2020

Conventional train energy calculation models cannot consider locomotive wheel-rail adhesions, traction adhesion control and locomotive dynamics. This paper developed an advanced model to fill this research gap. The model uses a 3D locomotive model with a fully detailed wheel-rail contact model. The locomotive model was integrated into a Longitudinal Train Dynamics model with the consideration of locomotive adhesion control. Energy consumption simulations using a conventional model (1D model) and the new model were conducted and compared. The 3D model reports less energy consumption than the 1D model. Maximum difference in energy consumption rate between the 3D model and the 1D model was 12.5%.
Variable Control Setting to Enhance Rail Vehicle Braking Safety
Authors: Shrestha Sundar , Spiryagin Maksym , Wu Qing
Published: August 2020

Train braking technology needs to be advanced corresponding to the vehicle advancement to fully utilize the benefits of the potential capacity, efficiency and to ensure safety. The effectiveness of the braking changes as the friction condition at the wheel-rail interface and speed of rail vehicle change. The conventional brake control systems do not differentiate these changes in conditions and consider a constant slip reference. To overcome this issue, a new control algorithm for a wheel slide protection device incorporated in the electronically controlled pneumatic brake system has been proposed. Unlike conventional controllers, the proposed controller is responsive to the change of operational and environmental parameters between wheel and rail. It is designed based on multiple modes shifting during operations as the friction conditions change which allows to utilize the maximum adhesion available and to prevent the occurrence of sliding. The control algorithm is developed in a modular approach, where the first module identifies the adhesion condition at the wheel-rail interface. The result from the first module is further implemented in the second module to search for the optimum slip range for that adhesion condition and vehicle speed. For numerical simulation, a wagon model considering in-train forces is developed. The adhesion force is modeled by a proper definition of an adhesion-creep characteristics curve achieved from measured data. The comparison between the proposed control algorithm and the conventional algorithm suggests that the proposed control algorithm can optimally utilize available adhesion between wheel and rail to ensure shorter braking distance while maintaining vehicle stability.
Toward Railway Automated Defect Detection From Onboard Data Using Deep Learning
Authors: Afzalan Milad , Jazizadeh Farrokh , Ahmadian Mehdi
Published: August 2020

Regular monitoring of railway systems is imperative for improving safety and ride quality. To this end, data collection is carried out regularly in the rail industry to document performance and maintenance. The use of machine learning methods in the past recent years has provided opportunities for improved data processing and defect detection and monitoring. Such methods rely on installing instrumentation wayside or collecting data from onboard rolling stock. Using the former approach, only specific locations can be monitored, which could hinder covering a large territory. The latter, however, enables monitoring large sections of track, hence proving far more spatial efficiency. In this paper, we have investigated the feasibility of rail defect detection using deep learning from onboard data. The source of data is acceleration and track geometry collected from onboard railcars. Such an approach allows collecting a large set of data on a regular basis. A long short-term memory (LSTM) architecture is proposed to examine the measured time-series to flag potential track defects. The proposed architecture investigates the characteristics of time-series signatures during a short time (∼ls) and classifies the associated track segment to normal/defect states. Furthermore, a novel automated labeling method is proposed to parse the exception report data (recorded by the maintenance team) and label defects for associated time-series signatures during the training phase. In a pilot study, field data from a revenue service Class I railroad has been used to evaluate the proposed deep learning method. The results show that it is possible to efficiently analyze the data (collected onboard a railcar operated in revenue service) for automated defect detection, with relatively higher accuracy for FRA type I defects.
Optimizing Power Consumption of Freight Railroad Bearings Using Laboratory Experimental Data
Authors: Lopez Carlos E. , Tarawneh Constantine , Fuentes Arturo , Siegal Harry
Published: August 2020

Based on projected freight truck fuel efficiency, freight railroad and equipment suppliers need to identify, evaluate and implement technologies and/or operating practices to maintain traditional railroad economic competitiveness. The railway industry uses systems that record the total energy efficiency of a train but not energy efficiency or consumption by components. Lowering the energy consumption of certain train components will result in an increase in its overall energy efficiency, which will yield cost benefits for all the stakeholders. One component of interest is the railroad bearing whose power consumption varies depending on several factors that include railcar load, train speed, condition of bearing whether it is healthy or defective, and type of defect. Being able to quantify the bearing power consumption, as a function of the variables mentioned earlier, would make it possible to obtain optimal operating condition ranges that minimize energy consumption and maximize train energy efficiency.

Several theoretical studies were performed to estimate the power consumption within railroad bearings, but those studies lacked experimental validation. For almost a decade now, the University Transportation Center for Railway Safety (UTCRS) at the University of Texas Rio Grande Valley (UTRGV) has been collecting power consumption data for railroad bearings under various loads, speeds, ambient temperatures, and bearing condition. The objective of this ongoing study is to use the experimentally acquired power consumption to come up with a correlation that can be used to quantify the bearing power consumption as a function of load, speed, ambient temperature, and bearing condition. Once obtained, the model can then be used to determine optimal operating practices that maximize the railroad bearing energy efficiency. In addition, the developed model will provide insight into possible areas of improvement for the next generation of energy efficient railroad bearings. This paper will discuss ongoing work including experimental setup and findings of energy consumption of bearings as function of railcar load, train speed, condition of bearing whether it is healthy or defective, and type of defect. Findings of energy consumption are converted into approximations of diesel gallons to quantify the effect of nominal energy consumption of the bearings and show economic value and environmental impact.