bluuebunny/crossref_metadata_2025 huggingface dataset:
The Emerging Render Alternatives: A Case Study Comparing the Utility and Aesthetics of the Printed and the 360 in Head-Mounted Display Formats for Architects and Non-Architects
Authors: Higuera-Trujillo Juan Luis , Rojas Juan-Carlos , Pistoni Pérez Mario , Iñarra Abad Susana
Published: January 2018

Environmental simulations are fundamental part of the architecture and design language. Different systems have been incorporated as technology has progressed. Renders, widely used in Architecture, also presents this development. Although the traditional printed presentation has not changed in recent years, new methods such as the 360-Render displayed on Head-Mounted Displays (HMD) have recently emerged. However, currently there are few systematic comparisons between them. Hence, the objective of this preliminary work was to quantitatively compare these systems support for design: printed Render, and 360-Render in HMD.

Bipolar subjective scales were used as measurement method. Concepts were involved in utility, credibility, understanding of the space and dimensions, and basic aesthetics-emotional aspects. Survey was directed to two profiles: architects and non-architects. The analysis reveals significant results regarding these concepts, formats, and profiles. Results allow reflection on the new means of representation, both in professional and pedagogical scopes.
Knee Joint Biomechanics for Various Ambulatory Exercises Using Inverse Dynamics in OpenSim
Authors: Butler Andrew B. , Caruntu Dumitru I. , Freeman Robert A.
Published: January 2018

Knee joint biomechanics for various ambulatory exercises was investigated using inverse dynamics in OpenSim, a computational platform for accelerated biomechanics research. A motion capture system was used to collect kinematic and kinetic information during walking, squatting, and the one-legged squat. Pre-processing of the data was accomplished using a MATLAB toolbox. Subsequent modeling, simulation, and analysis was performed in OpenSim. Loading in the cruciate ligaments and select muscles were the primary focus for the analysis. The accuracy of the results is compared with other available work in the literature. The impact, limitations, technology, and novelty were also reviewed in the scope of this work.
Response Analysis of a Circular Cylinder Undergoing Vortex Induced Vibrations Along Two Degrees of Freedom in the Presence of Noise
Authors: Aswathy M. S. , Sarkar Sunetra
Published: January 2018

In this study, we perform uncertainty quantification of a nonlinear dynamical system consisting of a circular cylinder undergoing free vibrations with two degrees-of-freedom in the presence of a fluctuating flow-field. Most of the studies in Vortex Induced Vibrations till now are conducted in a deterministic environment. Real life situations involving VIV are subjected to high amount of uncertainties, with the main culprit being the randomness in the incoming flow. Studies involving modelling of the flow with a prescribed set of parameters, represents only an idealistic situation and hence is not sufficient for a complete understanding of the associated dynamics. In this context, we make an attempt to characterise the flow by doing a stochastic modelling on the same. In the current study, we have mathematically modelled the noise through a uniform distribution. These fluctuations are superimposed on a mean flow at every time step. We use a Duffing Van der Pol combined system to model the structure and flow oscillators. It is observed that stochastic modelling brings noticeable changes in the structural responses both quantitatively and qualitatively. The influence of the fluctuations on both the transverse and inline oscillations have been studied. One of the most important changes in the response of the structure is in its amplitude. Noise amplifies the maximum amplitude attained both for transverse and inline oscillations. Further, additional qualitative types of responses are visible in the presence of noise which were absent in the deterministic environment. One such behaviour the ‘intermittent’ response which occurs during the transition from higher to lower amplitudes in the lock-in region. Intermittency is observed both for transverse and inline oscillations. It has been seen that the system undergoes stochastic Phenomenological bifurcations, which have been characterised by the probability density functions of both the transverse and inline responses.
Robust Adaptive Control of Uncertain Nonlinear Systems With Time-Varying Input Delay
Authors: Deng W. X. , Yao J. Y.
Published: January 2018

In this paper, a robust adaptive controller is proposed for a class of uncertain nonlinear systems subject to time-varying input delay, parametric uncertainties and additive bounded disturbances. The desired trajectory based adaptive feedforward technique and a predictor-like robust delay compensating term are integrated via backstepping in the controller design. The proposed controller theoretically ensures semi-global uniformly ultimately bounded tracking performance based on Lyapunov stability analysis by employing Lyapunov-Krasovskii (LK) functionals. Simulation results are obtained to illustrate the effectiveness of the proposed control strategy.
Modeling and Simulation of Saturator Temperature Control in Humid Air Turbine Cycle
Authors: Huang D. , Wei T. T. , Han H. C. , Zhou D. J. , Zhang H. S.
Published: January 2018

Humid Air Turbine (HAT) cycle is one of the most advanced gas turbine cycles in the world. It has drawn great attention due to its high efficiency and good environmental compatibility. The saturator is the key component in the HAT cycle, which utilizes liquid water to humidify compressed air to improve the system performance and make it possible to recover low temperature waste heat in the HAT cycle system. Therefore, saturator temperature control occupies very important position in HAT cycle, and it is essential to study the control logic in saturator. Saturator temperature control is a control strategy that adjusts the water flow rate to fit the designed temperature. In this paper, the HAT cycle test rig of Shanghai Jiao Tong University is taken as research object and a complete HAT cycle model using global heat and mass transfer coefficient is built to analyze the influence of saturator temperature control on both steady-state and dynamic performance of HAT cycle system. The system efficiency increases by 0.071% after considering saturator temperature control on 75% load. The dynamic response of output power changes little, while the saturator component can achieve stable faster. The research in this paper can lay the foundation for operation and control of the HAT cycle demonstration plants.
Thermo-Mechanical Response of Hybrid Polymer Composites During Tensile Loading
Authors: Prakash Raghu V. , Maharana Monalisha
Published: January 2018

The fiber reinforced polymers are candidate materials for critical applications in view of the high strength, stiffness characteristics; however, they are highly anisotropic and have complex failure mechanisms. Thermo-mechanical response characterization is one of the means of identifying damage progression in these materials.

In this study, tensile tests were conducted on the hybrid composite laminates and Infrared thermographs were used to capture the thermal response of the specimen for the entire range of loading till failure. The tests were conducted on natural fiber composite specimens and hybrid (natural + synthetic fiber) composite specimens. The natural fibers used were in the form of uni-directionally stitched mats of Sunhemp, Kenaf and Flax fiber. The synthetic fibers used were bi-directionally woven Carbon fiber mat and Glass fiber mat. All the laminates were prepared using the hand lay-up technique. Four different configurations of the laminates were prepared. The natural fiber composite laminate comprised of Sunhemp fiber mat in a polyester resin system. The Sunhemp fiber mat was also used with woven Glass fiber mat on one side to prepare an unsymmetrical hybrid laminate. The Kenaf fiber mat was placed between layers of woven Glass fiber mats whereas the flax fiber mat was placed between the woven carbon fiber mats; Epoxy LY 556 and hardener Araldite® was used as the matrix. The finished laminate thickness was 2.1 mm and dog-bone tensile specimens were extracted using a CNC router. Some of the specimens were impacted at low velocities from two different heights to study the change in thermo-mechanical response, post-impact, during tensile test. Temperature response as a function of applied stress, failure strain and work done suggests that there is a correlation between the fracture events that take place during tensile test with the temperature response. In cases where there was a ply-drop failure, the rate of temperature change could identify the failure events, even though the resultant peak temperature was less. When the specimen failed by a single mode of failure (delamination/fiber failure), the temperature rise was found to be proportional to the input work done during tensile testing.
Frequency Band Selection Based on a New Indicator: Accuracy Rate
Authors: Jin Yaqiang , Liu Zhiliang , Kang Jinlong , Yin Jie , Peng Dandan
Published: January 2018

Local defects in rotating machinery give rise to periodic impulses in vibrations. In order to acquire the information of these faults, various diagnostic methods have been proposed in the past decades. Most methods used the squared envelope spectrum (i.e., the spectrum of the squared envelope) as the final diagnostic tool, but different preprocessing steps were used before obtaining the envelope signal. The key problem is to obtain the center frequency and bandwidth of the fault signal, then analyze the envelope (squared envelope spectrum) of the band-pass filtered signal. The framework of accuracy rate method was proposed by means of cross validation of the nearest neighbor classifier in this paper: a) obtain the piecewise signal through original signal segmentation; b) calculate the feature of each piecewise signal; c) then an accuracy rate is calculated based on cross validation of the nearest neighbor classifier; and d) repeat the above steps in different frequency band, then find a frequency band with the maximum accuracy rate. Through this algorithm, we can obtain a fault frequency band, and then we can find out the type of the fault by the spectrum of the squared envelope. At the end of this paper, the proposed method is validated by two examples and compared with the other two diagnostic methods: conventional envelope analysis and Fast kurtogram. Through the comparison of results, the validity and superiority of this method has been proved.
Application of a Fractional Viscoelastic Material Model to Rubber in Comparison to a Linear Approach
Authors: Burgwitz Michael , Bothe Johan Steffen , Wangenheim Matthias
Published: January 2018

The modeling of material behavior is an important challenge in structural dynamics. While some materials can be well represented by a linear constitutive law, this becomes more complex when dealing with viscoelastic components. In this paper we investigate a fractional viscoelastic material model and present our results of research, focusing on its parametrical characteristics. We compare the results to a classical linear viscoelastic standard model and highlight advantages of the particular approach: we conduct monofrequent sinusoidal excitations using a DMTA (Dynamic Mechanic Thermal Analysis) machine. We use a viscoelastic TPU (Thermoplastic Polyurethane) sheet as sample and apply varying excitation frequencies and amplitudes. In a first modeling step we reproduce the experimental results with a fractional single degree-of-freedom system with promising results.
Nonlinear Vibrations of Woven Dacron Aortic Prostheses Conveying Pulsatile Flow
Authors: Tubaldi Eleonora , Amabili Marco , Païdoussis Michael P.
Published: January 2018

Woven Dacron grafts represent standard implants for replacements of the thoracic aorta in current medical practice. Wide knowledge about the distinctly different mechanical properties of the Dacron implants with respect to the native aorta is available in literature while very little is known about the dynamic behavior of these prostheses.

This study addresses the dynamic response to pulsatile physiological blood flow and pressure of woven Dacron grafts currently used in thoracic aortic replacements. The structural model assumes a cylindrical orthotropic shell described by means of the nonlinear Novozhilov shell theory. Residual stresses because of pulsatile physiological pressurization are evaluated and included in the model. The pulsatile flowing fluid is formulated using a hybrid model that contains the unsteady effects obtained from linear potential flow theory and the viscous effects obtained from the unsteady time-averaged Navier–Stokes equations. Physiological waveforms of blood pressure and velocity are approximated with the first eight harmonics of the corresponding Fourier series. Coupled fluid-structure Lagrange equations for a non-material volume with wave propagation in case of pulsatile flow are utilized.

Frequency-response curves in the physiological range show the geometrically nonlinear vibration response to pulsatile flow with several superharmonic resonance peaks in the high physiological frequency range. Different values of modal damping are considered; in the limit case of low modal damping values, flow-induced asymmetric vibration of the aortic prosthesis is possible.

Finally, in order to reproduce the weave design of the woven Dacron fabrics, geometric imperfections are introduced in the structural model. The numerical natural frequencies of the pressurized prosthesis are compared with the experimental results obtained from the modal analysis of a woven Dacron graft.
Study the Effect of Cerium Substituted Silicon-Zirconium Sol-Gel Coating on Hot Corrosion of Boiler Steel (SS 304)
Authors: Kapoor Jatinder , Singh Amrinder
Published: January 2018

High temperature corrosion is a grave problem in incinerators, boilers, turbines and IC engines. To prevent hot corrosion, alloying of metals is usually done. But it does not conserve mechanical properties like creep, toughness, ductility etc. Coating is a generic way to enhance the materials life at elevated temperature in the presence of salts. Sol-gel method of coating is easy and cheap as compared to thermal spray coatings. In the present work, Cerium substituted Silicon-Zirconium coating is prepared via Sol-Gel route. It is deposited on Chromium based super alloy SS-304. Sol-gel dip coating method is used for coating the materials. Cyclic oxidation tests are performed at 900°C in the presence of Na2SO4 salt solution on coated and bare samples. The weight gain analysis shows that coated samples have shown better corrosion resistance than bare specimen cyclic oxidation in simulated environment. SEM, EDS and X-ray mapping techniques are also confirmed that organic precursors of Silicon and Zirconium useful in creating uniform coating. However, coating showed cracks after calcinations which may be due to higher rate of drying. But cracks become self-healed when specimen was subjected to simulated environment at 900°C due to grain growth of Zirconium particles. X-ray mapping showed that protective layer of cerium and Zirconium present at surface of SS-304 and coating was successful in providing resistance to substrate metal from penetration of salts.
Effects on Balance When Interfering With Proprioception at the Knee
Authors: Lahiff Christina-Anne , Schlafly Millicent , Reed Kyle
Published: January 2018

After experiencing a stroke, 80% of individuals face hemiparesis causing muscle weaknesses, paralysis, and lack of proprioception. This often induces difficulty to perform everyday functions such as balancing. The goal of this project is to determine if stroke-like balance can be induced in healthy individuals. The Proprioceptive Interference Apparatus (PIA) applies vibrations and transcutaneous electrical nerve stimulation (TENS) about the knee joint in different combinations both with and without visual feedback.

Ten subjects stood on one foot for periods of two minutes for each of the eight trial conditions. The root mean squared (RMS) of the position coordinates, the standard deviation of the forces, and the RMS of center of pressure coordinates were analyzed for each trial and subject. Analysis of the variation of position markers and forces showed a statistically significant difference between balance with visual feedback versus without. However, the use of PIA did not have any statistically significant difference on these measures.
Dynamics of Droplet Deformation in Microchannels With Symmetric and Asymmetric Constrictions
Authors: Nath Binita , Borthakur Manash Pratim , Biswas Gautam , Dalal Amaresh
Published: January 2018

The investigation of the dynamics of a droplet traversing through constricted channels is an interesting field of research. In the present work, the motion and deformation of a neutrally buoyant droplet in planar constricted micro channels containing another immiscible fluid is studied computationally using an open-source finite-volume fluid flow solver, Gerris. The important non-dimensional parameters pertaining to such type of flow are — the Capillary number, which gives the relative importance of the viscous force over the surface tension force, the viscosity ratio between the dispersed and suspending medium and the ratio of the drop diameter to the channel height. Both symmetrical and asymmetrical constrictions are considered and results obtained are compared with a straight channel without any constriction. The parametric studies are conducted to study the effect of droplet size, viscosity ratio, Capillary number and presence of constriction in the channel. Depending on the parameters chosen, the drop extends to a maximum length as its front passes through the constriction and the deformation increases with the increase in number of constrictions. In the case of large drops, it is observed that the droplet disintegration rate increases in the presence of constrictions.
Numerical Simulation of Pig Motion in Two-Phase Flow With Stratified Pattern Pipelines Using the Flux-Corrected Transport Method
Authors: Patricio Rodrigo A. C. , Sondermann Carina N. , Figueiredo Aline , Bodstein Gustavo C. R. , Rachid Felipe B. de F.
Published: January 2018

To maintain efficiency and high productivity in pipeline operations, it is necessary to keep an updated maintenance program. To accomplish this goal, the use of pigs is a very common task, but not a simple one, since there are uncertainties and risks associated to their passage, especially inside long pipelines. For these reasons, it is important to understand how the motion of the pig impacts the line operation and vice-versa. Therefore, it becomes crucial to accurately predict the pig motion and the fluid flow within the pipeline. To do so, numerical simulations are the easiest and cost-effective way to address such a problem. This paper presents a mechanical model, along with a numerical scheme, to obtain approximate solutions to the resulting initial-boundary-value problem that describes the pig movement in a transient two-phase flow inside a pipeline. The model is discretized using the Flux-Corrected Transport (FCT) method along with the Petzold-Gear method. A numerical simulation was carried out for a foam pig travelling in a typical stratified-pattern two-phase flow in a gas pipeline and the obtained results were compared with the well-known commercial software OLGA.
Underwater Tracking System Based on Camera Space Manipulation: Static Calibration of GoPro Cameras
Authors: Martinez Martinez Felipe de Jesus , Blum Lillian , Rider Sabrina , Cárdenas Antonio , Piovesan Davide
Published: January 2018

Tracking of movement under water is still in its infancy. Difficulties include the designing experimental systems that are able to account for the distortion of dense media and the electrical insulation of the experimental apparatus. We propose a simple and inexpensive underwater system which combines the use of GoPro cameras and camera space manipulation (CSM) algorithms for the tracking of movements under water. A comparison of the GoPro cameras to standard computer vision cameras was performed to verify the effect of fisheye lens distortion on linear and non-linear CSM algorithm. Finally, calibration under water was performed using a linear CSM algorithm obtaining errors comparable with measurements obtained by standard cameras outside of water.
Ground Effect on Wings for Formula Student Race Cars
Authors: Epple Philipp , Hellmuth Manuel , Gast Stefan
Published: January 2018

Aerodynamic design is getting continuously more important for formula student race cars. One very important aerodynamic device of these cars is the front wing. The front wings, as well as the rear wings generate a downforce to improve the stability of the vehicle especially when driving on curves. The front wings are mounted so close to the ground that they are already in ground effect. The rear wings are already too far from the ground and therefore are not in ground effect. Therefore it is very important to design the front wings in such a way as to maximise the ground effect. Therefore these wings have to be mounted at a proper distance from the ground in order to have the maximum ground effect. If the front wings are too close to the ground the ground effect disappears or even the downforce is less than far from the ground. Since the rear wings are out of the ground effect they have not been considered in this investigation.

In this work a series of wing designs, with different aspect ratios, at different angles of attack and at different distances from the ground where designed and investigated with computational fluid dynamics using the commercial Navier-Stokes solver STAR CCM+. The downforce lift coefficients of these wings in free flight as well as in ground effect and as the corresponding drag coefficients are presented. The best configurations of aspect ratio and angle of attack as well as the optimum distances from the ground to operate these front wings in ground effect are shown and the results discussed in detail.
Operational Energy Comparison of Concrete and Foamed Geopolymer Based Housing Envelopes
Authors: Villalba José Luís , Macías José , Baykara Haci , Ulloa Nestor , Soriano Guillermo
Published: January 2018

The present article provides an operational energy comparison of modern concrete and foamed geopolymers as envelope materials for single unit housing in Ecuador. The study is performed by replacing the concrete material used in the walls and roof elements with foamed geopolymer components. Residential building sector requires around 35.6% of the total energy demand in Ecuador. For this reason, efforts on building practices improvement are relevant for the Ecuadorian society. The foamed geopolymers are a mixture of aluminosilicate material obtained from Ecuadorian natural zeolite, group of alkaline activators and the foamed agent that when mixing the raw materials and obtain the geopolymer.

To assess the potential use of foamed geopolymers as construction material, the annual energy demand for a social interest dwelling was obtained through simulation with EnergyPlus. Prefabricated Insulated Concrete Forms was established as the construction practice for the building model. Annual energy simulations were performed considering two Ecuadorian representative weathers, to Guayaquil and Quito locations.

Material properties of foamed geopolymers ware acquired by own experimental facilities. Thermal conductivity was obtained with the use of the hot plate method, while specific heat by means of differential scanning calorimetry (DSC) analysis. This analysis uses foamed geopolymers obtained from two procedures. Thus, these proposed materials presented low density, low thermal conductivity, and acceptable compressive strength values.

Finally, an assessment of natural geopolymers as a concrete replacement is presented, including a thermal characterization, and a sustainable construction evaluation. The findings affirm the key role of material selection in construction practices. Reductions around 4.0% in annual electricity demand was achieved for Guayaquil case, while energy consumption decreases around 1.3% for Quito.
An Extended Implementation of Fault Detection in Multi-State Systems Based on Warp Analysis: A Case Study on Natural Gas Transmission Systems in Tropical Regions
Authors: Pinzón Horacio , Audivet Cinthia , Portnoy Ivan , Consuegra Marlon , Alexander Javier , Sanjuán Marco
Published: January 2018

Natural gas transmission infrastructure is a large-scale complex system often exhibiting a considerable operating states not only due to natural, slow and normal process changes related to aging but also to a dynamic interaction with multiple agents overall having different functional parameters, an irregular demand trend adjusted by the hour, and sometimes affected by external conditions as severe climate periods.

As traditional fault detection relies in alarm management system and operator’s expertise, it is paramount to deploy a strategy being able to update its underlying structure and effectively adapting to such process shifts. This feature would allow operators and engineers to have a better framework to address the online data being gathered in dynamic on transient conditions.

This paper presents an extended analysis on WARP technique to address the abnormal condition management activities of multiple-state processes deployed in critical natural gas transmission infrastructure. Special emphasis is made on the updating activity to incorporate effectively the operating shifts exhibited by a new operating condition implemented on a fault detection strategy. This analysis broadens the authors’ original algorithm scope to include multi-state systems in addition to process drifting behavior.

The strategy is assessed under two different scenarios rendering a major shift in process’ operating conditions related to natural gas transmission systems: A transition between low and high natural gas demand to support hydroelectric generation matrix on severe tropical conditions. Performance evaluation of fault detection algorithm is carried out based on false alarm rate, detection time and misdetection rate estimated around the model update.
Phase Field Modeling of Solidification in Single Component Systems
Authors: Kavousi Sepideh , Moldovan Dorel
Published: January 2018

Using phase field modeling simulation approach we investigate the effect of various parameters on the primary and secondary dendrite arm spacing during directional solidification in a single component system. In previous studies the effect of temperature gradient was assumed to be negligible in the transversal directions with a temperature rate equal to the product of thermal gradient and solidification rate. In our study the temperature field is obtained from energy conservation equation by considering the balance of latent heat released in the regions where solidification occurs and energy dissipation due to directional temperature gradient as boundary condition. In our simulations, we implemented a numerical method that enables the investigation of solidification in larger domains. Specifically, the temperature and the order parameter equations are solved only in the domains close to the solidification front; approach that reduces the computational costs significantly. We investigate the interplay and the effect of thermal gradient, solidification rate, undercooling temperature, and the cooling heat flux on arm spacing. By using a well-established power law relation the primary and secondary arm spacing are calculated for various solidification parameters. We also show that, for large heat fluxes, the secondary arm spacing is almost constant for different undercooling temperatures; behavior that demonstrates the need for correction of the power law relation by including the effect of heat flux.
A Novel Algorithm for Solving the Assembly Line Balancing Type I Problem
Authors: Ismail Mohamed , Hossain Sayed Kaes , Rashwan Ola
Published: January 2018

This paper presents a new modeling approach called Progressive Modeling (PM) and demonstrates it by solving the Assembly Line Balancing Type I Problem. PM introduces some new concepts that make the modeling process of large-scale complex industrial problems more systematic and their solution algorithms much faster and easily maintained. In the context of SALBP-I, PM introduces a component model to deploy the problem logic and its solution algorithm into several interacting components. The problem is represented as an object-oriented graph G (V, E, W) of vertices, edges, and workstations which enables problem solutions to start anywhere. The novel representation relaxes the only forward and backward tracking approach used in the assembly line balancing literature. A set of well-reported problems in the literature are reported and solved. The paper concludes by demonstrating the efficiency of the new modeling approach and future extensions.
A Thermal Transient Model of Heat Transfer Within an Omnimagnet
Authors: Esmailie Fateme , Cavilla Matthew S. , Ameel Tim A.
Published: January 2018

An Omnimagnet is comprised of three orthogonal nested solenoids that enables magnetic guidance of devices such as medical implants. Electrical current within the solenoids leads to Joule heating resulting in undesired temperature increase within the Omnimagnet. If the temperature exceeds the melting point of the solenoid wire insulation, device failure will occur. Thus, a study of the heat transfer within an Omnimagnet is a necessity. In the present study, a thermal transient model was developed and validated with experimental data with maximum normalized root mean square error equal to 2.3%. A parametric study revealed that a reasonable operational range of input current for the tested Omnimagnet without active cooling is 0 to 9 A. At current higher than 9 A the maximum operational time is less than 2.5 min. Providing cooling to the Omnimagnet frame during heating or increasing convective cooling during cool down are effective methods to increase the maximum operational time of the Omnimagnet.
Joule-Heating Activated Flexible Composite Structures Using Shape Memory Epoxy
Authors: Wang Jingyu , Lee David , Liu Yingtao
Published: January 2018

In this paper, a novel shape memory epoxy based composites is employed to design and develop new flexible composites for aerospace applications. The epoxy and carbon fiber reinforced epoxy were first synthesized and characterized to understand their shape memory property. The characterized epoxy is used as the polymer matrix in carbon fiber reinforced composites. The shape memory function of the fabricated composites is experimental characterized using the Joule-heating based method. The Joule-heating based activation method using direct electrical current is systematically characterized to understand the shape recovery speed at different temperature. It was observed that the developed composites have good flexibility and response to Joule heat quickly during deployment. Such composite materials can be further used to design and develop flexible composites and aerospace structures, such as satellite panel trusses and solar sail boom structures.
Initial Results of a Bimodal, Ultrasound-Microwave, Imaging System for Early Detection of Breast Cancer
Authors: Ghanbarzadeh Dagheyan Ashkan , Molaei Ali , Obermeier Richard , Liu Chang , Martinez Aida Kuri , Martinez Lorenzo Jose
Published: January 2018

Unlike x-ray, ultrasound imaging (USI) uses nonionizing acoustic radiation to detect tumors in various body organs, including breast. In the reconstructed images, a radiologist can distinguish between a tumor and a non-malignant cyst, which is highly valuable in making true-positive diagnoses. However, clinical data shows that the addition of ultrasound to mammography, as a separate but auxiliary imaging tool, can increase the false-positive rates [1]. Nonetheless, in a co-registered manner, when an ultrasound image is used as prior information for another breast imaging modality, USI has the potential to make diagnosis more accurate. Previously, we presented the early results of a near-field radar imaging (NRI) system, developed as an add-on unit to the Digital Breast Tomosynthesis to enhance its low radiological contrast. In this work, the early results of a bimodal, USI-NRI, imaging system is presented by adding an ultrasound sensor to our previous system. A simple experimental configuration was utilized for the purpose of proving the concept. The initial results of this study can open the way for safer (in terms of radiation) and more accurate breast imaging in future.
Experimental and Numerical Study of Water Distillation Performance of Small-Scale Direct Contact Membrane Distillation System
Authors: Park Danielle , Norouzi Elnaz , Park Chanwoo
Published: January 2018

A small-scale Direct Contact Membrane Distillation (DCMD) system was built to investigate its water distillation performance for varying inlet temperatures and flow rates of feed and permeate streams, and salinity. A counterflow configuration between the feed and permeate streams was used to achieve an efficient heat exchange. A two-dimensional Computational Fluid Dynamics (CFD) model was developed and validated using the experimental results. The numerical results were compared with the experiments and found to be in good agreement. From this study, the most desirable conditions for distilled water production were found to be a higher feed water temperature, lower permeate temperature, higher flow rate and less salinity. The feed water temperature had a greater impact on the water production than the permeate water temperature. The numerical simulation showed that the water mass flux was maximum at the inlet of the feed stream where the feed temperature was the highest and rapidly decreased as the feed temperature decreased.
Synthesis, Stability and Selection Study of Oil-in-Water Nanoemulsions Containing Nigella Sativa L. Essential Oil
Authors: Usta Aybala , Rahman Muhammad , Asmatulu Ramazan
Published: January 2018

Targeted drug delivery has a great importance in cancer treatment and is in interest of many scientists worldwide. Targeted drug delivery renders local treatment of cancerous cells possible without affecting healthy cells. Hydrogels are promising materials to be used in targeted drug delivery systems due to their biocompatible nature and injectable behaviors where they can be used to load drugs. However, considering that not all the drugs are water soluble, entrapment of some drugs into hydrogels is not practical in terms of poor drug solubility and burst drug release because of this. At this point, an oil phase can be considered as a drug carrying agent, and entrapment of this oil phase into hydrogel would make it possible for in-situ injection of dissolved drug in oil phase.

Oil in water (O/W)-type nanoemulsions were prepared using black seed oil, which is known to cause apoptosis via p-53 dependent mechanism, water and Triton X-100, Span-80 surfactant combinations. Three different oil percentage and three different surfactant percentage were tested, and stability behaviors of nanoemulsions were investigated and compared. Dynamic light scattering analysis and zeta potential measurements were conducted for determination of particles sizes and surface charges of the nanoemulsions. The most stable nanoemulsion along with having smallest diameter and lowest polydispersity index (PDI) was used for further studies. Results indicated that using both hydrophilic and hydrophobic surfactants together increased the stability of nanoemulsions compared to those using either of them.
Failure Analysis of a Bellow at the Exhaust of a Diesel Engine on Board of an FPSO
Authors: Temani Ahmed , Seibi Abdennour C. , Chaari Majdi , Bouabdallah Abdelkader , Nasri Rachid
Published: January 2018

Floating Production, Storage and Offloading (FPSO) units are floating vessels used by the oil and gas industry offshore for the production and processing of hydrocarbons as well as storage of oil. It is equipped with the required facilities to produce, process, and store produced fluids. Among the equipment on board of the FPSO are pumps used to inject water or pump crude oil. This FPSO is fitted with seven positive displacement pumps powered by diesel engines; three for water injection and four for power fluid. At the exhaust of the driving engines, stainless steel bellows experienced frequent failures on a monthly basis; thereby, incurring a huge financial overburden on operating companies. Therefore, the aim of this paper is to explore the possibility of identifying some remedies to overcome this problem. The paper discusses the root causes of bellow failures attached to the exhaust system of a diesel engine on board of an FPSO. Effect of vibration, temperature, corrosion, and vessel rolling on the bellow structural response were investigated to identify the root causes of failure. A finite element modeling of the problem under study was conducted by taking into account the combined effect of thermo-mechanical loads. It was found that the thermal stress was well below the allowable stress. In addition, vibration analysis of the bellow-engine system revealed that the fundamental frequency of the bellow was way below the engine’s natural frequency. However, it was found that the vessel’s rolling generated an elevated stress that can cause failure of the bellow in a very short period time. The paper also presents some possible solutions to remedy or delay failure from occurring frequently as in this case.
Control Theory Practices Applied to Teaching Practical Control Theory
Authors: Stocco Leo , Galiano Ignacio , Paz Francisco , Rosales Roberto , Feixo David
Published: January 2018

Control theory is useful in a broad range of diverse applications that include mechanical, electrical and chemical systems. This work extends the application of control theory from achieving a desired technical outcome to achieving a desired pedagogical outcome. In this paper, the desired outcome is the teaching and learning of applied control systems theory. In the proposed model, the student is the plant, their skill set is the set point, the instructor is the controller, and either an exam or a project-based-learning (PBL) course is the sensor. The PBL course is used to evaluate the actual skill set of the students and the difference between the actual and desired skill set (error signal) is fed back to the professor to initiate curricular changes. This model is shown to be applicable at various levels. At the micro level, examinations within a course are used to optimize that course. At the intermediate level, a PBL course is used as the sensor for a conventional lecture-based course. At the macro level, the departmental program as a whole is matched to the needs of industry in pursuit of a 100% employment rate of its students.
Motion and Gesture Compliance Control for High Performance of a Wheeled Humanoid Robot
Authors: Rojas Salvador , Shen He , Griffiths Holly , Li Ni , Zhang Lanchun
Published: January 2018

Humanoid robots have the potential to help or even take the place of humans working in extreme or undesirable environments. Wheeled humanoids are robots that combine the mobility of mobile platforms, and the dexterity of an articulated body with two robotic arms. To perform like a human being, these robots normally are designed with a high center of mass, which makes it challenging to maintain stability while achieving high performance on complex and unpredictable terrain. Inspired from how humans react to balance themselves, a compliance control method is studied to help the wheeled humanoid robot developed at the Robotics Laboratory at Cal State LA achieve high dynamic performance while scouting over uneven terrain. Lagrange-Euler method is used to obtain the dynamic model of the humanoid robot. Then a nonlinear sliding mode compliance controller is derived and proven to ensure asymptotic stability of the humanoid robot while tracking desired reference trajectories. Finally, the performance of the proposed compliance control system is demonstrated using simulation. The results show that the robot successfully tracks a given input while maintaining balance based on the proposed tip-over avoidance algorithm.
Enhancing the Strengths of Adhesion Bonds Between Composite Surface and Coating via UV Treatments
Authors: Asmatulu R. , Erukala K. S. , Rahman M. M.
Published: January 2018

Field of composites is rapidly growing in many industries such as aviation, energy and automotive industries. Composites are known to have a high strength to low weight ratio. Significant improvement in the performance of coatings used in the protection of military and civil aircraft has been achieved the last thirty years. Composite coatings are exposed to many environmental conditions, which can significantly affect their properties. In this research, UV light treatment on the surface of composite was introduced to examine its effects on the adhesion properties between the coating and substrate. A cross-cut test was conducted on the composite panels to assess the adhesion of paint to the substrate after the treatments. Coating performance analyses were also carried out using a Fourier transform infrared spectrometer, water contact angle, and optical microscopic images. The first set of panels was treated with UV radiation for 0, 2, 4 and, 8 days, and the surface wettability was also assessed using the contact angle test. Two coats of paints, including a primer and top coat, were used, and the panels were exposed to UV radiation and immersed in water for 500 hrs and 1000 hrs. It was found that untreated panels showed a much higher contact angle of 106°, whereas the contact angle of panels treated with UV radiation was reduced to 47°. The cross-cut tests showed considerable flaking of the coating along the edges and squares of panels that were not treated, and very small flakes along the edges and parts of the grid square on panels that were UV treated, thus confirming the enhancement of coating adhesion between composite and coating surfaces by UV treatments.
Numerical Project for the Undergraduate Heat Transfer Course
Authors: Fadda Dani
Published: January 2018

A numerical simulation project, described in this paper, was assigned in an undergraduate heat transfer course in the mechanical engineering curriculum. This project complemented the heat transfer lecture course and its corresponding heat transfer lab. It was used to help students visualize and better understand the difference between conduction heat transfer which occurs within a three-dimensional solid body and the convection and/or radiation which occur at the surface of the solid body. It also allowed the students to generate and compare results of one dimensional heat transfer calculations to three dimensional simulation results.

The project contained well defined deliverables and an open-ended deliverable which allowed students to be creative. It gave the students reason to discuss the course outside the classroom. It allowed students to use SolidWorks heat transfer simulation and manage a MATLAB script without taking classroom time. It was appreciated and enjoyed by the students.
Mechanistic Cutting Force Prediction Model for Plunge Milling Considering Cutter Runout
Authors: Zhuang Kejia , Xu Xiaohu , Xiao Ruiqi , Zhu Dahu , Guo Shunsheng , Yan Sijie
Published: January 2018

As a kind of promising process for mass material removal in rough and semi-rough machining of hard-to-machine materials, plunge milling receives wide concerns and is often considered as one of the most effective methods in metal cutting operation, especially in aircraft industry. The cutting force in plunge milling operation differs from that in side milling or end milling for the complex geometries. To clarify the force based cutting mechanisms, a systematic study on cutting force modeling is conducted in this paper based on the precise cutting geometry which considers both the real-time uncut chip thickness calculation and cutter runout. The deduced cutting force model can be used for different cutting conditions in plunge milling process. Then, series of plunge milling operations with various cutting steps are implemented to verify the proposed force model. The results indicate that the predicted values show quite good agreement with the measured cutting forces.
Vibration Analysis of High-Speed End Milling Operations Applied to Injection Mold Materials
Authors: Logins Andris , Torims Toms , Rosado Castellano Pedro , Gutiérrez Santiago , Torres Rafael
Published: January 2018

High-speed milling has often been applied in injection mold manufacturing processes, where surface roughness is a significant criterion in product quality demands. It is equally applicable to automotive or industrial engineering and to toy manufacturing, where plastic parts with a high-quality surface finish have been processed using the injection molding technique. High-speed milling involves a number of process parameters that may affect the 3D surface topography formation. Literature analysis reveals that dynamical behavior is a significant factor in the end milling process on surface roughness parameters. To improve the accuracy of predicted surface topography models, it is important to include the dynamical behavior of milling factor.

This paper describes the surface prediction model of combined end-milling geometrical and dynamical interaction models. The natural frequency of machine assembly and forced vibrations during the cutting process were measured during the flat-end milling process. Unevenly distributed cutting marks were revealed by surface 3D topography images and microscopy images of the machined samples.

A mathematical model to predict surface topography was developed, including dynamical behavior and cutting geometries. Machine accuracy also has to be addressed. 3D surface topography parameters from the experimental sample provided the results for the mathematical prediction model. This model offers a software tool for manufacturers to improve the quality of machined part surfaces, taking into account the behavioral properties of their machining equipment. Relevant conclusions about the manufacturing equipment accuracy have been drawn. Vibrations in the milling system affect the cutting process and contribute to the surface topography prediction model. Local cutting tool vibrations do not have any influence on surface parameter mean values.
Numerical Analysis and Mechanical Properties of Nomex™ Honeycomb Core
Authors: Liu Yue , Gao Weicheng , Liu Wei , Hua Zhou
Published: January 2018

This paper presents an investigation on the mechanical response of the Nomex honeycomb core subjected to flatwise compressive loading. Thin plate elastic in-plane compressive buckling theory is used to analyze the Nomex honeycomb core cell wall. A mesoscopic finite element (FE) model of honeycomb sandwich structure with the Nomex honeycomb cell walls is established by employing ABAQUS/Explicit shell elements. The compressive strength and compressive stiffness of Nomex honeycomb core with different heights and thickness of cell walls, i.e. double cell walls and single cell walls, are analyzed numerically using the FE model. Flatwise compressive tests are also carried out on bare honeycomb cores to validate the numerical method. The results suggest that the compressive strength and compression stiffness are related to the geometric dimensions of the honeycomb core. The Nomex honeycomb core with a height of 6 mm has a higher strength than that of 8 mm. In addition, the honeycomb core with lower height possesses stronger anti-instability ability, including the compressive strength and stiffness. The proposed mesoscopic model can effectively simulate the crushing process of Nomex honeycomb core and accurately predict the strength and stiffness of honeycomb sandwich panels. Our work is instructive to the practical applications in engineering.