bluuebunny/crossref_metadata_2025 huggingface dataset:
Transfusion education for nurses and transfusion practitioners in Australia
Authors: Bielby L. , Peterson D. , Spigiel T.
Published: January 2018

Background

Transfusion risks and the principles and benefits of patient blood management (PBM) are well documented in the literature. One of the challenges is to ensure that all multidisciplinary team members working in these clinical areas are aware of the risks, benefits and principles, and undertake their practice accordingly.

Context

Nurses and transfusion practitioners need to have both knowledge and skills to undertake their roles safely and effectively. This is achieved predominantly through education and training across the continuum of the nursing career and is aligned with the practitioner's scope of practice and career path. It commences with acquisition of basic knowledge and development of competencies, through to the critical‐thinking and leadership skills, required to implement transfusion and/or PBM practice improvement initiatives within a clinical department/health service. Patients and carers need to be informed of the risks, benefits and any available alternatives, and nurses play a key role providing this information to support them being active partners in decision‐making as part of their care and treatment. There is a range of educational opportunities and delivery modes offered in Australia through:

Undergraduate curricula.

Continuing professional development.

Postgraduate qualifications offered through Blood Matters/The University of Melbourne.

Conclusion

Education is fundamental to ensure that staff working in the area of transfusion/PBM have the knowledge and understanding to provide high‐quality, effective and safe patient care. It is an ongoing process, requiring regular updates and reinforcement to keep pace with changes to reduce errors and risk and improve patient outcomes.
Machinability Analysis of Aluminum Alloy-Graphene Metal Matrix Composites Using Uncoated and DLC-Coated Carbide Insert
Authors: Joel J. , Anthony Xavior M.
Published: January 2018

Metal Matrix Composites (MMCs) based on Aluminum Alloys 2024, 6061 and 7075 reinforced with Graphene was fabricated using powder metallurgy process followed by hot extrusion process. The extruded samples were used for conducting the turning experiments to evaluate the machinability of the developed composites. Turning experiments were conducted in ACE Micromatic made CNC lathe as per the Design of Experiments (DOE) designed using L18 Taguchi’s mixed orthogonal array. Uncoated and DLC coated carbide inserts, along with three levels of cutting speeds, feed rates and depths of cut were considered for the turning experiments. During the experiments the cutting force generated was recorded “online” and subsequent to the experimentation the surface roughness generated on the work piece and the surface hardness for every trial were recorded. The influence of the cutting tool material and other cutting parameters on the machinability of composites was analyzed using ANOVA. The microstructural observation on the surface of the machined specimen reveals the detachment of reinforcement materials from the composite and their impact of the surface quality.
Use of the Moving Frame Method in Dynamics to Model Gyroscopic Control of Small Crafts at Sea: Experiment — Part 2
Authors: Teigland Håkon , Flåten Andreas , Lied Martin R. , C. Smith Caspar , Nyland Joakim F. , Stenfelt Gloria , Impelluso Thomas
Published: January 2018

This companion paper represents the experimental validation of a new mathematical method that models the gyroscopic control of small craft at sea. In light of the development of offshore wind farms, there is a need for stabilizing smaller vessels that transfer crew to and from the wind farms. One way of stabilizing floating vessels is by the use of gyroscopes (inertial spinning disks) mounted on the vessels. The research presented in this paper uses the Moving Frame Method (MFM) as the underlying analytical method. The companion paper introduces the method and provides the mathematical analysis. This paper presents the experimental validation. Tests performed in a wave tank are used to verify the equations obtained by using the MFM. The tests are performed using a scaled model of a floating vessel. The vessel motions are obtained by an inertial measurement unit (IMU). The data received from the IMU and equations obtained by using the MFM calculates appropriate gyroscopic nutation rates to reduce the vessels roll motions. The rates are then applied to the gyroscopes using servo motors. This research demonstrates the power of the MFM. More importantly, it shows how the MFM invites experimental validation tests, as it is fundamentally a 3D analysis, yet open to understanding and use by undergraduates. The authors request that reader review the companion paper previous to this one.
Theoretical Prediction and Experimental Validation of Dynamic Deformation During Machining of Thin-Walled Structure
Authors: Fei Jixiong , Lin Bin , Yan Shuai , Ding Mei , Zhang Xiaofeng , Zhang Jin , Lan Jin
Published: January 2018

Dynamic deformation of thin-walled structure during side milling is investigated in present paper. The component is modeled as a cantilever plate while the milling force is modeled as a moving excitation for the component. Classical plate theory is employed to construct the component motion equations. Modal superposition method is employed to solve the equation to obtain the dynamic deformation. At last, experiments and simulation are implemented, results of digital simulation and experiments are compared and they matched well with each other, which demonstrates the validation of the method for computing dynamic deformation in this paper. Moreover, analyzed results in this paper are also compared with FEM results which were obtained by other investigators and shows better accuracy.
Energy and Exergy Analysis of a Hybrid Solar System in Terms of Thermal Energy Production and Cooling
Authors: Koronaki I. P. , Nitsas M. T. , Papoutsis E. G.
Published: January 2018

In this study a hybrid solar system, already available in the Laboratory of Applied Thermodynamics at NTUA is examined in terms of thermal energy and cooling power production. The system is installed in Athens, Greece and it comprises of two types of solar collectors, namely one series of CPC-PVT (Compound Parabolic Concentrator-Photovoltaic Thermal) collectors and one series of ETC (Evacuated Tube Collector), one indirect water buffer with an intermediate heat exchanger and a commercial zeolite adsorption chiller (LTC vario, Invensor). Simulations are carried out in order to estimate the energy and exergy efficiency of the system, the produced cooling capacity as well as the thermal energy stored in the buffer. Moreover, the performance of the chiller is evaluated for various months by determining the Cooling Capacity and COP, both solar and thermal. In order to determine, if the proposed solar cooling system performs better than a conventional that covers the same load, the primary energy savings and the reduction of CO2 emissions are calculated. The operating cost savings are also estimated. The simulation results show that the under study systems can indeed work sufficiently when the specific types and surface of collectors are considered. In specific, the system exhibits an average COP of 0.5 for the under study period while its solar exergy efficiency (nearly 2.5%) leads to the conclusion that the system, especially the collectors, can undergo an optimization process.
Generation and Investigation of Embedded Micro-Channels Network Using Three Dimensional Printing Technology
Authors: Smith Austin , Bardaweel Hamzeh
Published: January 2018

The work presented here is motivated by the recent growing interest in using additive manufacturing to fabricate micro-channels networks. Distorted shapes and rough geometries influence hydrodynamic characteristics of micro-channels by increasing their flow resistance and pressure drop or altering wall shear stresses inside them. Since geometric conformity and shape fidelity of micro-channels networks are greatly influenced by manufacturing process, this work is focused on dimensional characterization of micro-channels fabricated using additive manufacturing. In this work, circular and rectangular cross-section micro-channels are 3D printed. Shapes and dimensions of 3D printed micro-channels are examined using Scanning Electron Microscope (SEM) imaging. In this work, 500 μm diameter and 200 μm square transparent PolyLactic Acid (PLA) micro-channels are 3D printed with average errors 0.25% and 1.65%, respectively. SEM images confirmed geometric conformity and shape fidelity of the 3D printed circular and rectangular cross-section micro-channels. Statistical analysis is performed on multiple prints to verify reproducibility and shape conformity. Results show that factors such as printing direction play essential role in the shape conformity and geometric fidelity of the micro-channels. Although 3D printing is a promising route for attaining micro-channels there are still significant improvements that can be made to the precision of the printer in the XY plane for printing small geometric figures. This improvement will likely come as the printing technology and software both improve to allow the operator more control over the outcome of the print. Additionally, new 3D printing materials may open the gate for new applications in different fields such as thermal management and microfluidics.
Computational Fluid Dynamics Validation of the Upper Respiratory System
Authors: Taherian Shahab , Rahai Hamid , Bonifacio Jeremy , Lopez Samuel , Lee Yong , Jafari Behrouz , Waddington Thomas
Published: January 2018

Verification of numerical results with experimental data is an important aspect of any in silico study. In the case of the upper respiratory system, the air flow is often turbulent, which highlights the importance of validating an accurate turbulence model for numerical simulations. Patient specific CT based upper airway models were used for computational fluid dynamics (CFD) analyses of the upper respiratory system and the results were compared with the corresponding experimental results. Detailed CFD simulations were conducted using the STAR-CCM+ software to investigate the most appropriate numerical approach in accurately predicting flow characteristics in the upper respiratory system. Large Eddy Simulations (LES) and Reynolds-Averaged Navier-Stokes (RANS) equations with k-ε, and k-ω turbulence models were investigated.

The experiments include simulating inspiratory-expiratory flow with particle injection at the intake. A stereolithographic (SL) system (3-D system Projet 6000HD), with a resolution of 0.001–0.002 inches per inch of part and VisiJet SL Clear material, was used for fabricating the experimental model. The outlet of the model was connected to a manifold, with subsequent connection to a piston-cylinder system where a computer-controlled motor was used to simulate the normal breathing flow conditions. Investigations of flow characteristics within the upper airway were performed with a 2-D µPIV system from Intelligent Laser Applications (ILA for micro particle image velocimetry) which includes a high power green LED light source with an effective area of 100×100 mm, and a pulsing system (LPS controller). Matlab software was used for the post processing of PIV images.

The LES results displayed more detailed transient flow characteristics than the RANS results for both turbulence models. At the early time steps, the numerical results of the average velocity from all three methods were nearly identical. However, further downstream, where obstructions and strong velocity gradients exist, results differ with a larger velocity gradient near the wall for the LES simulation. Comparing the numerical and experimental results, due to seeding limitations, the experimental results did not display detailed low speed flow characteristics and thus, the shear stress and turbulence quantities were less than the corresponding CFD results. Further experiments are currently in progress to improve the experimental results and to better assess the transient numerical and experimental results.
Modeling the Drill Bit for Rotational Burying Steel Pipe for Ground Source Heat Exchanger
Authors: Kakizaki Takao , Saito Akinori , Oguma Masahito , Kageyama Chiaki
Published: January 2018

In this paper, the modeling of a drill bit for the rotational burying steel pipe for a ground source heat exchanger is addressed. The objective of this study is to clarify the relationship of the bit design and bit penetration mechanism by model analysis and experiment. First, the detail of the rotary buried steel pipe pile used for the foundation pile of residential houses is explained. Then, the short heat exchanger well formed by foundation pile is explained. Moreover, the concept of the drill bit modeling for the rotational burying steel pipe pile is explained. The main feature of the modeling method is employing simple plane patches to approximate relatively complicated 3D curved surfaces which forms the 3D bit blade surfaces. Using this method of quasi-static modeling, the thrust force and starting torque of blade type, convex type and hybrid type bits can be computed for their penetration characteristics. Based on the modeling, the drill bit design procedure using a conventional general-purpose CAD system and the bit prototyping using a 3D printer are explained. The prototyping results of the designed bits are also precisely presented. Finally, the experimental results of the designed bits are presented. The relationship between the bit rotation, the penetration depth, and starting torque have been measured. The effect of the bit blade angle on the penetration is investigated and compared with the analysis using the developed bit modeling.
Flow Analysis of the M151 Aircraft Model Using the Academic CFD Code Galatea
Authors: Inglezakis Dimitrios A. , Lygidakis Georgios N. , Nikolos Ioannis K.
Published: January 2018

CFD (Computational Fluid Dynamics) solvers have become nowadays an integral part of the aerospace manufacturing process and product design, as their implementation allows for the prediction of the aerodynamic behavior of an aircraft in a relatively short period of time. Such an in-house academic solver, named Galatea, is used in this study for the prediction of the flow over the ARA (Aircraft Research Association) M151/1 aircraft model. The proposed node-centered finite-volume solver employs the RANS (Reynolds-Averaged Navier-Stokes) equations, combined with appropriate turbulence models, to account for the simulation of compressible turbulent flows on three-dimensional hybrid unstructured grids, composed of tetrahedral, prisms, and pyramids. A brief description of Galatea’s methodology is included, while attention is mainly directed toward the accurate prediction of pressure distribution on the wings’ surfaces of the aforementioned airplane, an uncommon combat aircraft research model with forward swept wings and canards. In particular, two different configurations of M151/1 were examined, namely, with parallel and expanding fuselage, while the obtained results were compared with those extracted with the commercial CFD software ANSYS CFX. A very good agreement is reported, demonstrating the proposed solver’s potential to predict accurately such demanding flows over complex geometries.
A Novel Methodology to Determine Optimal Active Marker Scanner Placement
Authors: Schmitz Anne , Piovesan Davide
Published: January 2018

Motion capture is a common technology used to measure human motion. One key aspect to collecting an ample amount of accurate data is maximizing the motion capture volume. This maximization is typically gone by a trial and error method. The purpose of this study was to develop a better method to determine the camera placement to maximize the captured volume. Two active marker scanners were methodically placed at various locations around a circle centered on a forceplate. The scanner placements of optimal coverage were defined as the position of the scanners when the area of overlap between the two scanners was maximum and the area of uncovered walkway at a minimum. The optimal placement of the scanners occurred when one scanner was placed at (−1.718, 2.459) meters with respect to the forceplate origin and the other positioned at (0.7691, −2.9) meters. Although these dimensions are specific to the constraints and walkway of our lab, the method can be adapted to any lab size. This setup is crucial to establish so accurate, un-occluded marker data can be collected in future studies.
Carbon Footprint of Energy Systems: Liquefied Petroleum Gas Based Cooking vs Electricity Based Cooking in Ecuador
Authors: Ramirez Angel D. , Perez Edgar F. , Boero Andrea J. , Salas Daniel A.
Published: January 2018

Cooking is one of the most important final household uses of energy. In Ecuador, the main energy carrier for this use is liquefied petroleum gas (LPG), which normally is supplied in bottles. LPG is imported and heavily subsidized for household consumption. The Government has promoted the use of electric induction stoves provided the hydropower generation capacity in Ecuador is projected to grow.

Sustainability issues should be considered when changes in energy systems are analyzed. Life cycle assessment (LCA) is a methodological framework that can be used to quantify the environmental performance of any product or service, including energy systems. LCA can be used to quantify a range of environmental impact categories including Climate Change. The life cycle greenhouse gas emissions of a product or service are also known as carbon footprint.

The objective of this study is to quantify the change in the carbon footprint of the household cooking system from the current based on LPG to the proposed based on electricity, and the cumulative energy demand (CED) for cooking with both technologies, using the LCA methodology, in order to provide a basis for the development of policies to reach the maximum mitigation of greenhouse gases (GHG). Several scenarios that consider different electricity generation mixes, cooking efficiency and emissions profile are studied. The functional unit for comparison was defined as “1 effective MJ”, which is 1 MJ transferred to the food during cooking. System boundaries for the assessment included resources extraction, processing, energy carrier supply, cooking and manufacturing of the stove.

The results depend highly on the carbon footprint of the electricity system and, in a lesser extent, on the stove efficiency. Main results indicate that a carbon footprint mitigation occurs when changing the conventional LPG to a highly hydropower based cooking system, and that a higher life cycle energy efficiency is obtained when a high stove efficiency is considered. However, a greater carbon footprint may occur when cooking is performed using fossil derived power, which is a possible case when cooking is performed during peak demand of electricity.
Tolerances and Uncertainty in Robotic Systems
Authors: Proctor F. , Franaszek Marek , Michaloski J.
Published: January 2018

The ability to be programmed for a wide range of tasks is what differentiates robots from dedicated automation. Consequently, robots can be faced with often-changing requirements and conditions. Conventional application development based on teach programming takes robots out of production and occupies personnel, limiting robots’ effectiveness in these environments. Off-line programming solves these problems, but robot inaccuracy must be compensated by a combination of calibration, compliance, and sensing. This complicates up-front systems engineering and application development, but results in systems that can operate in a wider range of requirements and conditions. Performance can be optimized if application tolerances and process uncertainties are known. If they often change, optimization must be done dynamically. Automating this optimization is a goal of smart manufacturing. With its trend of increasing connectivity between the components of robotic systems both within workcells and to the enterprise, exchanging this information has become more important. This includes tolerance information from design through process planning to production and inspection, and measurement uncertainty from sensors into operations. Standards such as ISO 10303 (STEP), the Quality Information Framework (QIF), the Robot Operating System (ROS), and MT-Connect support this exchange to varying degrees. Examples include the assignment of assembly tasks based on part tolerances and robot capabilities; the automated generation of robot paths with tolerances arising from sensed obstacles; and the optimization of part placement to minimize the effects of position uncertainty. This paper examines requirements for exchanging tolerance and uncertainty in robotics applications, identifies how these requirements are being met by existing standards, and suggests improvements to enable more automated information exchange.
A Numerical Study on Shock Wave Mitigation Using Layered Composites
Authors: Sadeghi Hossein , Magallanes Joseph , Crawford John
Published: January 2018

Phononic crystals are composites with architected microstructure that exhibit superior shock mitigation properties which cannot be achieved through natural materials. In this study, the capability provided by layered phononic crystals for protection of structures subjected to near-contact detonation is investigated. To evaluate the protective performance of the layered composite, finite element simulation of a reinforced concrete (RC) column, with a layered composite attached to its surface, subjected to near-contact detonation is performed. As a reference case, the same RC column under the same near-contact detonation, without the layered composite, is also studied. Contours of damage and residual load carrying capacity of the RC column are analyzed for both cases. It is observed that due to optimized band-gap in the composite, high frequency components of the shock wave are filtered, while the low frequency components of the shock front are highly scattered. Therefore, the intense shock front with large peak overpressure and short duration gets dispersed and transforms into a wave with a longer duration and lower peak overpressure. Comparing the damage pattern in the protected RC column with the bare column, high level of protection provided by the layered composite is demonstrated. This study provides insight on how stress waves can be controlled through microstructural design of phononic crystals through topology optimization to achieve a desired dynamic and structural response.
Starting Base Position Optimization in Integrated Task Planning for Mobile Manipulators Painting Large Workpieces
Authors: Yu Qiankun , Wang Guolei , Ren Tianyu , Hua Xiaotong , Chen Ken
Published: January 2018

In order to paint large workpieces, heavy painting manipulators are always transported by mobile platforms due to their limited workspaces. To reduce the vibration of the end-effector, the base velocity of the manipulator is constant when painting. In this operation mode, the Starting Base Position (SBP) of the manipulator is important to attain the maximum manipulability and dexterity. This paper aims to optimize the SBP for painting a specified surface efficiently. An approximated decouplable model of painting manipulators is first built to get the analytically expressed inverse kinematic solutions. Then joint-level criteria for one manipulating point reflecting the manipulability and dexterity are proposed, followed by the combined criterion for a painting task about SBP with consideration of the platform velocity. Afterwards, the SBP optimization problem is translated into a least squares problem. To solve such a problem, an initial SBP value is first calculated through an algorithm based on internal penalty function method. Then a modified Levenberg-Marquardt method is employed to get the optimal SBP. Results of applications on painting a straight and an arc path indicate that the method proposed is effective and efficient.
Implementation of Student Presentation-Based Active Learning (SPAL) Approach in Undergraduate Engineering Curriculum
Authors: Xu Jiajun
Published: January 2018

Active learning approaches require a lot of time investment in student activities and engagement during the class period, which often leads to incomplete coverage of the course syllabus. Furthermore, it requires significant amount of time for the instructor to design and implement active learning strategies. All these shortcomings are often cited as the common hindrance in adopting student active learning. To address these widely recognized inhibiting factors, we recently implemented a new student active learning approach. This approach is based on the students’ presentation and hence termed as student presentation-based active learning (SPAL). Under this approach, students are given a reading assignment to prepare a PowerPoint presentation on well-defined conceptual topics, questions, or chapter modules. Reading assignments on a topic are administered 1–2 weeks before covering them in the class. This allows reasonable time for the self-comprehension of the suggested material for presentation preparation. Students were expected to rehearse the presentation and be prepared to complete it in the suggested time duration. During each lecture, one group of student would present the assigned topic to the class, and their presentations were graded according to the rubric focusing on the coverage of suggested topics, quality of presentation, and after presentation discussions. Peers and instructor provided feedback about the students’ presentation and unclear concepts. To understand the efficacy of this approach, this approach was implemented in Mechanical Engineering Senior Capstone Project I course in Fall 2016. Here the responses and insights garnered from this practice were presented, and discussion on the advantages and challenges associated with the adaptation of this approach in teaching engineering courses as compared to lecture based classroom education system. This paper can provide useful insights for instructors considering this approach or similar student active teaching approach in their courses.
FEM Stress Analysis and the Load Factor of Bolted Joints Consisting of Dissimilar Hollow Cylinders Under Tensile Loads
Authors: Sawa Shunichiro , Ishimura Mitsutoshi , Sekiguchi Yasuhisa , Sawa Toshiyuki
Published: January 2018

In designing a bolted joint consisting of dissimilar hollow cylinders, the load factor (the ratio of an increment in axial bolt force to an external tensile load) is important. In the present paper, the effect of the load application point, the ratio b/a of the outside diameter to the inside diameter of dissimilar hollow cylinders, Young’s modulus ratio between the dissimilar hollow cylinders on the load factor and the interface stress distribution are examined using FEM calculations. As a result, it is found that the values of the load factor decrease as the ratio b/a increases and the positions where the load application point approaches the interfaces while the value of the load factor is independent of the bolt preload. In addition, it is found that the value of the load factor is less than 0.1 for steel and steel hollow cylinder joints, it is less than 0.2 for aluminum and aluminum hollow cylinder joints and it is less than 0.15 for aluminum and steel hollow cylinder joints while the material of bolt is steel in the present study. For verification of the FEM calculations, experiments to measure the load factor and a load when the interfaces start to separate were carried out. The FEM results are in a fairly good agreement with the experimental results. Finally, based on the obtained results, a design method for bolted joints with dissimilar hollow cylinders is demonstrated for determining the nominal bolt diameter and the bolt strength grade.
Process Parameter Analysis of Higher D/T Ratio Tube Formed From Sheet Hydroforming
Authors: Tian Duanyang , Shu Xuedao , Wei Yilun , Wang Yu
Published: January 2018

As a core part of the aero engine casing, the thin-walled tube with large diameter usually formed by sheet hydroforming presents high forming precision and forming quality. In this paper, the appropriate hydraulic pressure and blank holder force should be identified to control the wall thickness uniformity of N08811 alloy tube with large diameter. Firstly, the stress-strain curve of this material at room temperature is obtained from deep drawing tests. Subsequently, within the allowable range of springback and wrinkling errors, finite element simulation and the uniform test design are performed to investigate the effect of the multi-level process parameters on the thickness uniformity of the higher D/t ratio tube. Results show that the blank holder force and the hydraulic pressure produce significant effects on the wall thickness uniformity. Finally, the regression analysis is further carried out for the computational results from uniform experimental design experiments. The optimized process parameters are then obtained and the wall thickness uniformity of the tube is improved. These results provide a theoretical reference for improving the forming quality of thin-walled tube with large diameter.
Flow Patterns and Wall Shear Stress Distribution in Human Vertebrobasilar System: A Computational Study to Investigate Smoking Effects on Atherosclerotic Stenosis at Different Ages
Authors: Sharifi Alireza , Salari Ali , Taebi Amirtaha , Niazmand Hamid , Niazmand Mohammad Javad
Published: January 2018

The blockage of arteries in the human vertebrobasilar system (VBS) usually results in major disability or death. It has been widely seen that atherosclerotic stenosis occurs at locations with a low wall shear stress or a high oscillatory shear index. This study investigates the potential of developing arteriostenosis due to smoking in the human VBS at 3 different ages. For this purpose, the VBS has been modeled for smoking/nonsmoking subjects that are 20, 50, and 70 years of age. The governing equations were discretized and solved by a finite volume-based software (ANSYS Fluent v15.0). Five potential locations for stenosis were determined along the VBS. The quantified risks of stenosis were found for smoking and nonsmoking groups, indicating that the locations prone to stenosis are at a higher risk in smoking subjects. The stenosis probability increases around vertebrobasilar junction point (VBJ) and along the right vertebral artery in the 50 and 70-year-old smoker subjects, respectively. Also, the results suggested that the area around the VBJ is at higher risk levels for stenosis at different ages for both smoking and nonsmoking subjects.
Experimental and Computational Study of Flow and Heat Transfer Around a Surrogate Engine Mount
Authors: Verma Navni N. , Iacob Andrei , Mazumder Sandip , Selamet Ahmet
Published: January 2018

An experimental and computational investigation is conducted on the flow and heat transfer characteristics on and around a surrogate engine mount. The engine mount in an automobile is often in the close proximity of the catalytic converter, and may be subjected to considerable thermal radiation, combined with thermal conduction from the engine block through its bracket. The objective of this study is to develop a validated model that is capable of accurately predicting the temperature distribution on the mount. Two sets of heaters were implemented in the present study, both with controllable temperatures: band heaters to approximate the catalytic converter and cartridge heaters to represent the effect of the engine block at the bracket base. Carefully controlled experiments were first conducted with fixed heater temperatures, air flow rates, and bracket (at the base of the mount) temperatures. The temperatures were recorded at 22 different locations along the mount surface and the mount bracket for all input conditions. A computational fluid dynamics (CFD) model was next developed to simulate the same experiments. The simulations were conducted using roughly 5–6 million control volume (cells). The mesh was generated using ANSA™ and parallel computations of the governing equations were conducted using Ansys-Fluent™. For the broad matrix of cases considered, average predicted temperatures were found to agree with experimentally measured temperature to within 10°C (out of 300°C total variation), while local temperatures were found to agree within 10%.
Effect of Extrusion Processing Parameters on Microstructure of Mg-Zr Alloys
Authors: McGhee Paul , Yarmolenko Sergey , Pai Devdas , Xu Zhigang , Kotoka Ruben , Neralla Sudheer , McCullough Matthew , Sankar Jagannathan
Published: January 2018

The micro-alloying effect, mechanical properties, and plastic deformation behavior of extruded Mg-Zr alloy were investigated and characterized as a function of Zr addition, grain size, and texture. The experimental methodology used in this study was design to exploit the hot-extrusion processing parameters (in the terms of extrusion ratios and temperature) and its effect on Mg extruded alloys microstructure, texture, and mechanical properties. Microstructural observations revealed significant grain refinement through a combination of Zr addition and hot-extrusion, producing fine equiaxed grain structure with grain sizes ranging between 1–5 μm. Texture analysis and partial compression testing results showed that the initial texture of the extruded alloy gradually evolved upon compressive loading along the c-axes inducing contraction twinning creating a strong basal texture along the extrusion direction. Full tensile and compression test at room temperature showed that the combination of hot-extrusion and Zr addition can further refine the grains of the Mg alloys microstructure and enhance the texture while simultaneously enhancing the mechanical properties.
Experimental Study of Fire Behavior in a Depressurized Aircraft Cargo Compartment
Authors: Li Cong , Yao Yina , Tao Zhenxiang , Yang Rui
Published: January 2018

To analyze the fire behavior in the dynamic pressure environment, a series of n-heptane pool fire experiments were conducted in an 8.11m × 4.16m × 1.67m simulated aircraft cargo compartment. The compartment is capable of mimicking flight environment from taking off to landing of the aircraft according to the standards of Federal Aviation Administration (FAA) by a pressure control system. Pool fires with 30cm diameter were tested under the dynamic pressure from 101kPa to 45kPa with various depressurization rates of 10kPa/min, 15kPa/min, 20kPa/min and 25kPa/min. Fire behavior such as burning rate, oscillation frequency and flame temperature were analyzed. The results revealed that the dynamic pressure influences the burning rate not only during the depressurization stage but also after depressurization. The oscillation frequency increases with the pressure decrease but has no relationship with depressurization rate. The flame temperature at different heights shows various tendencies with pressure.
Wear Performance of New Textured Surfaces Created by Modulation Machining
Authors: Tock Andrew , Gandhi Rahul , Saldana Christopher , Iglesias Patricia
Published: January 2018

Methods for scalable surface texturing continues to receive significant attention due to the importance of micro-textured surfaces toward improving friction, wear and lubrication ability of mechanical devices. Controlled textures on surfaces act as fluid reservoirs and receptacles for debris and wear particles, reducing friction and wear of mating components. There are numerous fabrication techniques that can be used to create micro-sized depressions on surfaces, but each has limitations in terms of control and scalability. In the present study, modulation-assisted machining (MAM) is demonstrated as a viable approach to produce such textures, offering a potentially cost-effective approach for scalable production of these features on component surfaces.

In this work, the wear behavior of several textured surfaces created by MAM was studied using a ball-on-flat reciprocating tribometer. Textured and untextured alloy 360 brass disks were mated with stainless steel AISI 440C balls under lubricated conditions and variable sliding distance. The textured surfaces exhibited noticeably reduced wear under the longer sliding distances and the tribological performance of the surfaces depended on the size of the micro-dimples. Wear mechanisms are elucidated from the optical microscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) observations and the implications for using such surfaces in practice are briefly discussed.
A Novel Platform-System to Study the Effects of a Vestibular Prosthesis on Non-Human Primate Postural Control
Authors: Thompson Lara A. , Haburcakova Csilla , Lewis Richard F.
Published: January 2018

For the several millions of vestibular loss sufferers nationwide, daily-living is severely affected in that common everyday tasks, such as getting out of bed at night, maintaining balance on a moving bus, or walking on an uneven surface, may cause loss of stability leading to falls and injury. Aside from loss of balance, blurred vision and vertigo (perceived spinning sensation) are also extremely debilitating in vestibular impaired individuals. For the investigation of implants and prostheses that are being developed towards implementation in humans, non-human primates are a key component.

The purpose of our study was to implement a distinctive balance platform-system to investigate postural responses for moderate to severe vestibular loss and invasive vestibular prosthesis-assisted non-human primates (rhesus monkeys) for test balance conditions of various task-difficulty levels. Although the need for vestibular rehabilitative solutions is apparent, postural responses for a broad range of peripheral vestibular function, and for various stationary and moving support conditions, have not been systematically investigated.

The measurement system used in this research was unique in that it allowed us to conduct animal experiments, not investigated previously; such experiments are necessary towards the development on an invasive vestibular prosthesis to be used in humans suffering from vestibular loss. Our platform-system facilitated the study of rhesus monkey posture for stationary support surface conditions (i.e., quiet stance and head turns; more versus fewer footplate cues and large versus small base-of-support) and for dynamic support surface conditions (i.e., pseudorandom roll-tilts of the support surface). Further, the platform-system was used to systematically study postural responses that will serve as baseline measures for future vestibular-focused human and non-human primate posture studies.
Investigating Female Athletes’ Balance Using Center-of-Pressure (COP) Derived Displacement and Velocity Parameters
Authors: Badache Mehdi , Behera Lonika , Zhang Nian , Thompson Lara A.
Published: January 2018

A realization of how specific exercises relate to balance performance is important for a wide demographic of individuals. Maintaining active and healthy living is particularly important for balance-impaired individuals (e.g., otherwise healthy individuals recovering from injury, fall-prone elderly, and stroke survivors) whom are interested in improving their balance for function in daily life. However, balance performance is also important for persons that are unimpaired (e.g., athletes). How balance performance may be improved as a result of, and in relation to, various athletic activities and exercises is a common question. Further, how certain activities can be used to prevent injury is an ultimate goal. Our objective was to compare standing balance in 3 unimpaired groups (i.e., female track & female tennis collegiate athletes and female non-athletes).

To assess static balance, participants performed stance variations increasing in difficulty-level, utilizing a wide or tandem stance (increasing or decreasing support base) and eyes-open or eyes-closed (limiting or providing visual cues), while standing on a forceplate walkway. Through the recorded ground reaction forceplate-based, center-of-pressure (COP) position time series, we extracted velocity and displacement parameters that aided in identifying differences between the above groups.

Our general findings were that anterior-posterior (AP, or front-to-back) COP displacement and velocity measures for female track athletes were unchanged relative to the (baseline) female non-athletes. However, mediolateral (ML, or side-to-side) measures, which have previously been shown to be associated with fall-risk, showed observable differences in displacement and velocity parameters, particularly for the female track athletes. Specifically, the female track athletes were better able to control their ML COP velocity in eyes-closed, wide, and eyes-open tandem conditions compared to non-athletes. However, tennis athletes had difficulty balancing in situations where eyes were closed (vision eliminated) and feet were tandem (base-of-support decreased) which was made apparent by the increases in all AP and ML COP-derived parameters. We interpreted this finding as the female tennis athletes were trained to rely heavily on visual cues (e.g., hand-eye or eye-body coordination), and also their balance may be more focused on maintaining their center-of-mass stability and body orientation, as opposed to COP per se.

Our study lends new insights as to how various types of athletic activities, and reliance on vision in athletes, impacts balance performance in un-impaired females.
Convective Heat Transfer of Parallel-Flow and Counter-Flow Double-Layer Microchannel Heat Sinks in Staggered Arrangement
Authors: Shen Han , Zhang Yingchun , Yan Hongbin , Sunden Bengt , Xie Gongnan
Published: January 2018

Previous research has proved Double-layer Microchannel Heat Sinks (MHSs) to be efficient ways to improve the cooling performance of electronic devices. However, the cooling potential of the upper working liquid cannot be fully utilized to cool down the substrate with the heated elements. In this sense, a concept of staggered double-layer MHS is proposed and designed. The parallel and counter flow directions are considered to investigate the flow arrangement effect. The Reynolds number effect, Nusselt number and pressure drop are analyzed in detail and compared with those of a parallel straight double-layer MHS. It is found that the staggered double-layer MHSs exhibit much better heat transfer enhancement and overall thermal performance compared with the parallel straight double-layer MHS. For the staggered double-layer MHSs, the counter flow case is superior to the parallel flow case. This research provides a new structure design to enhance the heat transfer in microchannel heat sinks and broad application prospects for heat sinks in the thermal management of high power density electronic devices.
Study of Skin Friction Coefficient of Incompressible Flow on High Lift Devices Using CutCell Mesh
Authors: Ghmati Ramadan , Jawad Badih , Hamieh Abdallah , Yee Kingman , Liu Liping
Published: January 2018

With advances in computing power and Computational Fluid Dynamics (CFD) algorithms, the complexity of CutCell based simulation models has significantly increased. In this study three dimensional numerical simulations were carried out for steady incompressible flow around an airfoil shape. The authors extended their previous work on more complex geometries; a NACA-23012 wing with 20 percent C Clark Y flap was used for this study. The boundary layer thickness, mesh expansion ratio, and mesh density variation parameters were examined. The skin friction coefficient vanishes where the flow separation starts. Although there is no experimental data available to compare the simulation work the results can be subjected to future work experimentally.
A Case Study of Decentralized Off-Grid Water Treatment Using Reverse Osmosis
Authors: Baghaei Lakeh Reza , Andrade Daniel , Miller Kyle J. , Du Bowen , Pham Joshua , Modabernia Mohammad M. , Ng Pui Y. , Nguyen Thuan N. , Nguyen Justine L. , Mena Crystal , Anderson Kevin R. , Sharbatmaleki Mohammadali
Published: January 2018

Decentralized water treatment consists of a variety of water treatment techniques for dwellings, industrial facilities, homes, and businesses independent of the power grid. According to the United States Geological Survey, brackish groundwater is abundant in the southwestern states including California; hence it can potentially be considered a new source for California’s water portfolio. Most of membrane-based desalination technologies (e.g. reverse osmosis) have high energy demand and cost. Using renewable energy (mostly solar photovoltaics) in concert with membrane-based water desalination can be utilized to develop decentralized and off-grid brackish water desalination systems especially for remote and rural regions. In this paper, the results of a case study on decentralized off-grid brackish water system have been presented and discussed. The system utilizes a high pressure pump that can provide a feed flow rate of 2.2 gpm of at 140 psi. The system is run by solar photovoltaic panels through a battery bank. The results of the study show that the system is capable of treating brackish water at a salt rejection rate of more than 97.5% and a recovery rate up to 80%.
Experimental Determination of the Efficiency of a Multi-Speed Bicycle Transmission
Authors: Bolen Rachel , Archibald Mark
Published: January 2018

The efficiencies of gears in a multi-speed bicycle gearbox transmission were measured and efforts were taken to establish measurement repeatability. Data collected from this apparatus challenges manufacturers to improve their product lines. Given that cyclists are limited in their ability to sustain power supplied through pedaling, minimizing drivetrain losses is very important. Previous researchers have measured various bicycle drives, including chains and belts, multi-speed derailleur sets and multi-speed hub gear transmissions. This study continued to measure the efficiency of a Pinion P1.12 multi-speed crank transmission. Repeatability studies were performed using a custom apparatus, capable of providing a wide range of input speed, output power and configuration adjustments and the experiment procedure was adjusted accordingly. Efficiency was evaluated as the ratio of flywheel power to motor power over fourteen combinations of crank speed and output power for each gear. The means and 95% confidence intervals for these efficiencies were calculated, and a nonlinear regression was used to model the data as an exponential function of output torque. The mean of the means was calculated and fit with an exponential curve. Gear efficiency was determined to be the efficiency at infinite output torque, although this theoretical value is only approached at moderate cycling torques. Results indicate these transmissions are comparable to many modern multispeed geared bicycle hubs, ranging from 91.6–94.95%. Single-speed and derailleur systems can obtain higher efficiencies. However, the Pinion transmission provides enhanced reliability, reduced maintenance and relocates the majority of the drive weight to the middle of the bicycle. A repeatability study was conducted on the P1.12 transmission.