bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of adrenergic stimulation on sex differences in left ventricular twist mechanics
Authors: Williams Alexandra M. , Shave Rob E. , Cheyne William S. , Eves Neil D. 
Published: February 2017

Key points
Sex differences in left ventricular (LV) mechanics occur during acute physiological challenges; however, it is unknown whether sex differences in LV mechanics are fundamentally regulated by differences in adrenergic control.
Using two‐dimensional echocardiography and speckle tracking analysis, this study compared LV mechanics in males and females matched for LV length during post‐exercise ischaemia (PEI) and β1‐adrenergic receptor blockade.
Our data demonstrate that while basal rotation was increased in males, LV twist was not significantly different between the sexes during PEI. In contrast, during β1‐adrenergic receptor blockade, LV apical rotation, twist and untwisting velocity were reduced in males compared to females.
Significant relationships were observed between LV twist and LV internal diameter and sphericity index in females, but not males.
These findings suggest that LV twist mechanics may be more sensitive to alterations in adrenergic stimulation in males, but more highly influenced by ventricular structure and geometry in females.
AbstractSex differences in left ventricular (LV) mechanics exist at rest and during acute physiological stress. Differences in cardiac autonomic and adrenergic control may contribute to sex differences in LV mechanics and LV haemodynamics. Accordingly, this study aimed to investigate sex differences in LV mechanics with altered adrenergic stimulation achieved through post‐handgrip‐exercise ischaemia (PEI) and β1‐adrenergic receptor (AR) blockade. Twenty males (23 ± 5 years) and 20 females (22 ± 3 years) were specifically matched for LV length (males: 8.5 ± 0.5 cm, females: 8.2 ± 0.6 cm, P = 0.163), and two‐dimensional speckle‐tracking echocardiography was used to assess LV structure and function at baseline, during PEI and following administration of 5 mg bisoprolol (β1‐AR antagonist). During PEI, LV end‐diastolic volume and stroke volume were increased in both groups (P < 0.001), as was end‐systolic wall stress (P < 0.001). LV twist and apical rotation were not altered from baseline or different between the sexes; however, basal rotation increased in males (P = 0.035). During β1‐AR blockade, LV volumes were unchanged but blood pressure and heart rate were reduced in both groups (P < 0.001). LV apical rotation (P = 0.036) and twist (P = 0.029) were reduced in males with β1‐AR blockade but not females, resulting in lower apical rotation (males: 6.8 ± 2.1 deg, females: 8.8 ± 2.3 deg, P = 0.007) and twist (males: 8.6 ± 1.9 deg, females: 10.7 ± 2.8 deg, P = 0.008), and slower untwisting velocity (males: 68.2 ± 22.1 deg s−1, females: 82.0 ± 18.7 deg s−1, P = 0.046) compared to females. LV twist mechanics are reduced in males compared to females during reductions to adrenergic stimulation, providing preliminary evidence that LV twist mechanics may be more sensitive to adrenergic control in males than in females.
Selection of Vibro-Characteristics for Monitoring Flange Integrity in the Field Conditions
Authors: Palmov Vladimir , Malinin Len 
Published: February 2017

Monitoring of flange integrity in the field traditionally has been based on evaluating bolt tension and deriving pressure on the gasket from these data. Multiple techniques of evaluating bolt tension based on measuring speed of propagation of a longitudinal wave (time of flight), or ratio of speeds of longitudinal and shear waves (“L+S method”), demonstrate 5–10% accuracy in the controlled laboratory conditions [1]. However, accuracy in the field, on the flanges exposed to harsh environment, is often worse than 20%, which makes it difficult to evaluate flange integrity and predict a leak. The need for knowing acousto-elastic parameters of steel (in case of L+S method) may also present a hurdle.
Tools based on measuring a shift of the resonance frequencies (RF) are commercially available, though RF are relatively robust to tension, and require a reliable data processing procedure to discern the proper peaks. Evaluation of tension based on natural modes is more sensitive, but relatively complex and costly. Use of transfer functions (TF) offers several advantages over both RF and natural modes, as TFs depend on both RF frequencies and natural modes, and a properly selected parameter of TF can offer greater sensitivity.
Generic Steel Vehicle Front Bumper and Crush Can Assemblies Subjected to a Rigid High Speed Offset Frontal Impact
Authors: Seyed Yaghoubi A. , Begeman P. , Newaz G. , Board D. , Chen Y. , Faruque O. 
Published: February 2017

This study presents experimental investigations of generic steel Front Bumper and Crush Can (FBCC) assemblies subjected to a 40% offset frontal impact. As automotive industries aim to reduce overall vehicle weight by applying lighter-weight materials to its structures, component-level studies become important. Computer aided models are valuable tools to complement physical testing by assessing the performances of these structures. Due to the lack of studies on component-level tests with FBCCs, a novel component-level test procedure would be useful to aid in CAE correlation. A sled-on-sled testing method was used to perform all the tests reported here. Impact speed was optimized such that there was no bottoming-out force for this type of test. Three high-speed cameras (HSCs), an infrared (IR) thermal camera, and several accelerometers were utilized to study impact performance of the FBCC structures.
The results showed that time histories of displacement and velocity from video tracking and accelerometers were in good agreement. The force-time history and force-displacement curves from different FBCC specimens were consistent and in good agreement with respect to each other with a low coefficient of variation calculated. Post-impact deformation pattern analysis of the samples showed consistent crush patterns. Heat was generated and dissipated at the tip of the crush can and progressed as the can started to fold.
Life Centered Design Using Morphological Chart
Authors: Jawaharlal Mariappan , Ellingwood Stephanie Nguyen , Thokchom Kiranbala 
Published: February 2017

Traditional engineering design is a customer-centric approach that focuses on maximizing performance objectives and minimizing costs under resource constraints. This approach may be effective in meeting the needs of a particular customer but may be detrimental for a larger group of people. A more inclusive human-centered design attempts to deal with a broader base of customers extending beyond geographical boundaries. Inadequacy of even this approach is apparent, as only humans are the center of this design paradigm.
Life Centered Design (LCD) is different from traditional design methodology. It accounts for all forms of life by creating beneficial symbiotic relationships between humans and other living matters leading to sustainability. Nature has solved most problems we face in some form, and it continues to inspire humans. In this context, the LCD approach makes perfect sense as a concept. The challenge, however, is to find solutions using the LCD approach. How do engineers, who avoided biology in the first place, identify potential solutions from nature for solving problems in hand?
This paper proposes the use of morphological charts in the early design phase to generate potential solutions. Specifically, the objective is to develop a structured system that will enable industry innovators to correlate everyday engineering functions with those available in nature. By developing a morphological chart with this correlation, engineers and designers can now identify and create life-friendly designs.
Steel Sheets Impact Simulation for Safety Guards Design: Problems and Perspectives
Authors: Landi Luca , Amici Damiano 
Published: February 2017

The growing need of design of safety guards for industrial workers led to the need for experimentation in the field of ballistics, typically used in the military research.
In the last few years some international standards for the safety of machine tools have been developed, such as the ISO 23125: 2010, improving the ballistic protection of safety guards. But it is still possible to find in the market a large quantity of machine tools with doubtful real protective characteristics of guards.
The uncontrolled projection of parts of work piece or tools can often cause very dangerous perforations of the safety guards. In such a way specific experimental tests like the ones conducted in EU, have assured the possibility to write appendices of ISO standards for safety guards design of machine tools.
These tests are based on impact between a particular standardized projectile, which exemplifies an impacting fragment of variable size and energy, and a flat plate placed in the trajectory of the projectile. The penetration or buckling of the target determines the non-suitability of a particular material of a given thickness, for the design and production of safety guards.
However these tests, have the following limitations: they are valid only for: a limited type of thickness and materials, a perpendicular impact with flat plates of about 500 mm × 500 mm and when the standardized penetrator is a cylinder with a prismatic head.
Moreover another limitation arises for the design of real safety guards: difficulties in taking into account curved design of guards such as the ones typically used in the spindles of machine tools. Moreover it is very difficult to take into account innovative materials different from the ones provided by the standards and also it is impossible to consider projected objects whose geometry is not regular, for example fragmented parts of tools, broken as a result of a wrong manoeuvre of the machine user.
The main focus of this paper is to test the applicability of numerical methods for the simulation of impacts on steel sheets of standardized penetrators for the numerical design and validation of industrial safety guards.
Correlation between experimental penetration tests found in international papers and optimized numerical tests will be presented.
Analysis of an Adsorption Chiller Cooling System for Various Types of Solar Collectors Using the F-Chart Cooling Method
Authors: Koronaki I. P. , Papoutsis E. G. , Nitsas M. T. 
Published: February 2017

Solar cooling systems offer a reliable and environmentally friendly alternative to conventional electrically driven vapor compression cooling units. Air conditioning systems powered by solar energy are very attractive because they have zero ozone depletion and global warming potential, their operational cost is low and they do not burden the electrical network during summer months.
In this study, the installation of a solar cooling system in various Greek cities is examined. The system utilizes a single-stage, two-bed silica gel-water adsorption chiller driven by heat produced by solar collectors. A lumped parameter model is used to simulate the performance of the adsorption chiller. The optimum tilt of the solar collectors is calculated for each examined city in order for the collected solar energy to be maximized during the summer period (April to September). The climatic data are taken from the technical notes of Greek Regulation for Buildings Energy Performance. Then, using the f-chart cooling method the necessary collectors’ surface area is estimated for every examined city and for different types of flat plate collectors (including advanced flat plate, simple flat plate and hybrid photovoltaic thermal collectors).
Transient Multiphase Simulation in Separator Vessel Internals Design in Saudi Aramco
Authors: Al-Khalifa Hussain A. , Oshinowo Lanre , A. Al-Saif Omar 
Published: February 2017

The design of new multiphase separation plants or the replacement of vessels represents an opportunity to review and update the separation systems, to ensure the surface facilities lifetime with maturing production conditions. Potentially adverse operating scenarios involving slug flow could occur in the production header, leading to potentially damaging fluid forces acting on the high-pressure production trap internals. The internals design is based on the fluid forces occurring during a slug flow condition.
This paper presents the application of 3-D Computational Fluid Dynamics (CFD) to simulate the realistic fluid forces acting on a novel separator inlet device, and to assess the structural integrity of the mechanical design. To generate slug conditions resulting from several adverse, but low probability, operating scenarios, OLGA, a 1-D transient multiphase flow hydraulic simulation application, was used to simulate the transient multiphase flow conditions in the production header entering the production separator using the 20-year production forecast. In a one-way coupling, the output from OLGA is used as input to the CFD model. The scenarios were carefully developed, thoroughly evaluated and agreed on by the different project stakeholders — technical services, operations and project management teams.
The OLGA simulations produced the transient phase velocities and hold-ups that were applied as inlet boundary conditions to the CFD models of the separator. The transient CFD turbulent multiphase simulations used the Volume-of-Fluid model to track the gas-oil-water mixture in the inlet device and the inlet section of the separator. A discussion on the appropriate CFD multiphase model selection is presented. The hydrodynamic forces computed in the CFD model are integrated over the internal surfaces of the inlet device and mapped as a distributed pressure load for a Finite Element Analysis (FEA) structural model, to determine the mechanical reactions of the structure, a fluid-structure interaction (FSI) analysis. The methodology developed is intended for use in new internal designs for two- and three-phase separators, and slug catchers in gas/oil separation plants (GOSPs).
Development and Validation of a Predictive Algorithm for Near-Optimal Control of Venetian Blinds
Authors: Karizi Nasim , Reddy T. Agami , Dasgupta Partha 
Published: February 2017

Application of integrated centralized control systems in buildings has been shown to be a very promising option to reduce energy consumption. The focus of this paper is on automated day-lighting systems which can modulate window blinds and electrical interior lights for maintaining the proper illumination levels and saving significant electrical energy in buildings.
The algorithm proposed involves developing a preliminary baseline strategy for near-optimal blind slat angle settings for venetian blinds. We describe the predictive algorithm and validate the algorithm through experimental studies in both a virtual test cell as well as in an actual test room which have three separate sets of venetian blinds. The baseline strategy involves using a detailed lighting simulation program to predict illumination levels during selected days of the year and specific times of the day. The simulations are done by modifying the angels of blinds individually by pre-selected increments. It is then shown that this baseline data when properly extrapolated is adequate to predict near-optimal blind angles for most of the hours during the rest of the year.
The study presented in this paper lays the foundation towards the development of an innovative integrated lighting control algorithm for high performance buildings using distributed sensors which will be described in a subsequent paper.
Hydrogen Production From Methane Steam Reforming With CO2 Capture Through Metallic Membranes
Authors: Carapellucci Roberto , Favre Eric , Giordano Lorena , Roizard Denis 
Published: February 2017

As an energy carrier, hydrogen has the potential to boost the transition toward a cleaner and sustainable energy infrastructure. In this context, steam methane reforming coupled with carbon capture through membrane separation is emerging as a potential route for hydrogen generation with a reduced carbon footprint. A potential way to improve the efficiency and reduce costs of the entire process is to integrate the hydrogen production system with a gas turbine power plant, using a fraction of waste heat exhausted to provide the heat and the steam required by the endothermic reforming reaction.
The paper assesses the techno-economic performances of a small-scale hydrogen and electricity co-production system, integrating a syngas production section, a gas turbine and a membrane separation unit.
The simulation study investigates two main configurations, depending on whether the gas turbine is fed by hydrogen or natural gas. For each configuration, energy and economic performance indices are evaluated varying the main plant operating parameters, i.e. the steam reforming temperature, the permeate sweep dilution, the membrane pressure ratio and the technology of gas turbine.
Mist Cooling Technology for Thermoelectric Power Plants
Authors: Gokkus Enes , Bahadur Vaibhav 
Published: February 2017

A novel mist-based cooling concept is analyzed with the objective of reducing water consumption in thermoelectric power plants. Additionally, this concept offers the potential to increase electricity generation capacity. The concept involves the integration of two independent mist-based technologies. In the first technology, the cooling tower is replaced with a two stage heat exchanger consisting of air-cooled and water mist-cooled sections. The mist-cooled heat exchanger chills the cooling water to near wet bulb temperature ambient, which enables lowered condenser pressures and temperatures. Enhanced evaporation control through mist cooling allows the mist to reach temperatures closer to wet bulb temperature conditions than cooling towers. In the second technology, the shell-and-tube steam condenser is replaced with a direct contact condenser, wherein Rankine cycle steam condenses on water mist streams. The large area offered by mist droplets increases heat transfer rates significantly, resulting in compact, low maintenance condensers.
Analyses show that mist cooling technology can reduce water consumption by up to 65 %, compared to present-day cooling towers of the same power output. Furthermore, by reducing the condenser pressure, electricity generation can be increased by 4 % while still consuming less water than cooling towers. First-order techno-economic analyses reveal that mist cooling technology can benefit 17 out of 18 coal-fired power plants in Texas. It is expected that this technology will significantly benefit other U.S. power plants located in water-stressed areas.
Simplified Spur Gear Design
Authors: Osakue Edward E. 
Published: February 2017

A simplified design method (SDM) for spur gears is presented. The Hertz contact stress and Lewis root bending stress capacity models for spur gears have been reformulated and formatted into simplified forms. A scheme is suggested for estimating the AGMA J-factor in Lewis root bending stress for spur gears from a single curve for both pinion and gear instead of the conventional two curves. A service load factor is introduced in gear design that accounts for different conventional rated load modifier factors. It represents a magnification factor for the rated load in a gear design problem.
Two design examples are considered for applications of the stress capacity models. In Example 1, the Hertz contact stress of the SDM deviates from AGMA value by 1.95%. The variance in Example 2 between the contact stress of the SDM and FEM is 1.184% while that between SDM and AGMA is 0.09%. The root bending stress of AGMA and SDM for the pinion in Example 1 differs by 1.44% and that for the gear by 6.59%. The difference between the root bending stress of AGMA and SDM for pinion and gear in Example 2 is 0.18%. These examples suggest that the new simplified method gives results that compare very favorably with both AGMA and FEM solutions. The simplified method developed is recommended mainly for preliminary design when quick but reliable solutions are sought.
Risk Management for Rail Safety: Post Lac Megantic
Authors: Raghunathan Vijay , Mitchell Ron , Pitblado Robin , Wu Hong 
Published: February 2017

Following several recent serious rail accidents in North America, changes in regulation and increased public awareness is driving the need to address gaps in rail safety. The industry and regulators have numerous safety initiatives; however prescriptive standards in combination with a performance based approach could be a powerful tool for understanding and mitigating risk in a cost effective way.
This paper reviews the principles of safety risk management that can be applied to safe transportation of flammable hydrocarbons by Rail. FRA’s proposed rulemaking on Risk reduction program and its potential impact on the industry are also addressed.
The approach proposed in this paper focuses on existing and new proposed safeguards/barriers and how they could be monitored and managed. The paper aims to set the path forward for structured risk based thinking in managing rail safety. The first part of the paper explains the barrier based risk assessment approach using the Lac Megantic accident as an example. A bow-tie is developed to deconstruct the incident timeline and to capture the safeguards that existed at that time and their working status. This diagram cross references Transport Canada’s Investigation findings.
The second part of the paper evaluates the new mitigation measures proposed by FRA HM 251 rulemaking (“Enhanced Tank Car Standards and Operational Controls for High-Hazard Flammable Trains” Final Rulemaking”) as potential safeguards and their impact on the overall risk of transportation. A baseline risk is first established for transporting crude by rail assuming some common safeguards in place. A simple Quantitative Risk Assessment methodology including likelihood and consequence was then used to estimate the base case risk. Risk mitigation and effect of any additional new measures like Changes in Rail Tank Car design, Oil Conditioning, Enhanced Braking to Mitigate Damage in Derailments, Speed Limit changes, Positive train control, Train manning when loading are assessed.
Active Torque Vectoring in High Speed Lane Change Maneuvers
Authors: Steinbock Nathaniel , Prange Laura , Fabien Brian C. 
Published: February 2017

Emergency lane changes are often the best course of action when avoiding obstacles on the road, but this maneuver has the possibility of sending the vehicle out of control. The University of Washington EcoCAR team has a hybrid-electric vehicle outfitted with an electric drivetrain and variable torque control to each of the rear wheels. Each rear wheel has an electric motor that is independently controlled to provide torque to the wheel. A lateral vehicle dynamics model is used to develop a torque control strategy to improve the safety and maneuverability of a modified hybrid-electric 2016 Camaro as part of the EcoCAR 3 competition.
The specific scenario simulated is a two-lane lane change at a speed of 55 mph. We would like to increase the yaw and lateral accelerations that the vehicle can perform safely by controlling differing torques out of the two motors. Regulating these accelerations requires a control strategy over the left and right motor torques. Equal-torque control of the electric motors will be used as a baseline.