bluuebunny/crossref_metadata_2025 huggingface dataset:
Nurse experiences of medication administration to people with swallowing difficulties living in aged care facilities: a systematic review of qualitative evidence
Authors: Forough Aida Sefidani , Wong Simon Y.M. , Lau Esther T.L. , Santos Jose Manuel Serrano , Kyle Greg J. , Steadman Kathryn J. , Cichero Julie A.Y. , Nissen Lisa M.
Published: January 2018

Objective:

To identify nurses’ experiences of administering oral medications to residents of aged care facilities (ACFs) with swallowing difficulties.

Introduction:

Administering medicines to older people with swallowing difficulties is a challenging task. Nurses frequently modify oral medications e.g. by crushing/splitting tablets or opening capsules, to facilitate the administration process. These practices are associated with an increased risk of medication administration errors. However, the reasons for these practices from the nurse's perspective are not well understood.

Inclusion criteria:

The review investigated studies on the experiences of nurses of any level with the responsibility of medication administration in ACFs in terms of problems and challenges they encountered when administering oral medicines to aged care residents with swallowing difficulties. Aged care facilities providing all levels of care were considered for inclusion. Qualitative studies including, but not limited to, phenomenology, grounded theory, ethnography and action research designs as well as mixed methods studies and text and opinion papers were considered.

Methods:

A comprehensive database search of PubMed, CINAHL, Embase and Scopus was conducted between October and December 2016. MedNar and ProQuest Dissertations and Theses were used to search for gray literature. No date limitation was applied. The Joanna Briggs Institute Qualitative Assessment and Review Instrument critical appraisal tool (JBI-QARI) was used to assess the quality of the papers. The JBI-QARI data extraction instrument was used to extract qualitative findings. Data synthesis was not applicable in the final analysis due to the inclusion of only one article.

Results:

The initial search resulted in 1681 unique titles for screening. A total of 202 abstracts were screened, after which a full-text review conducted for 19 articles. After the full-text review, only one article was eligible to be included in the final report. The included study scored highly in terms of methodological quality. The findings highlighted issues around time constraints, complexity of medication administration process to residents of ACFs with swallowing difficulties, cost and resources for alternative strategies, inefficient information flow and communication among healthcare professionals, and nurses’ knowledge and training needs.

Conclusion:

The limited findings of this systematic review indicate that further research is necessary to provide evidence of nurses’ experiences with regards to administering oral medications to older people with swallowing difficulties living in ACFs. A comprehensive understanding of these experiences may lead to organizational system changes to support nurses and older people with swallowing difficulties in ACFs.
Geriatric Nursing Sensitive Indicators and quality nursing care for the older person: a scoping review protocol
Authors: Griggs Kim , Wiechula Richard , Cusack Lynette
Published: January 2018

Review question:

The objective of the scoping review is to locate and describe the international literature relating to Nursing Sensitive Indicators (NSIs) and their use in evaluating geriatric care. Specifically the review question is: What definitions and key concepts of NSIs are identified in the current literature that are relevant in evaluating nursing care of the older person?

Findings from the review will inform future research and health care responses to support the provision of quality nursing care to the older person.
Optimum Heat Source Temperature and Performance Comparison of LiCl–H2O and LiBr–H2O Type Solar Cooling System
Authors: Pandya Bhargav , Kumar Vinay , Patel Jatin , Matawala V. K.
Published: January 2018

This comprehensive investigation has been executed to compare the thermodynamic performance and optimization of LiCl–H2O and LiBr–H2O type absorption system integrated with flat-plate collectors (FPC), parabolic-trough collectors (PTC), evacuated-tube collectors (ETC), and compound parabolic collectors (CPC). A model of 10 kW is analyzed in engineering equation solver (ees) from thermodynamic perspectives. Solar collectors are integrated with a storage tank which fueled the LiCl–H2O and LiBr–H2O vapor absorption system to produce refrigeration at 7 °C in evaporator for Gujarat Region of India. The main objective includes the evaluation and optimization of critical performance and design parameters to exhibit the best working fluid pair and collector type. Optimum heat source temperature corresponding to energetic and exergetic aspects for LiCl–H2O pair is lower than that of LiBr–H2O pair for all collectors. Simulation shows that FPC has lowest capital cost, exergetic performance wise PTC is optimum, and ETC requires lowest collector area. On the basis of overall evaluation, solar absorption cooling systems are better to be powered by ETC with LiCl–H2O working fluid pair.
Toward a Universal Social Impact Metric for Engineered Products That Alleviate Poverty
Authors: Stevenson Phillip D. , Mattson Christopher A. , Bryden Kenneth M. , MacCarty Nordica A.
Published: January 2018

One of the purposes of creating products for developing countries is to improve the consumer's quality of life. Currently, there is no standard method for measuring the social impact of these types of products. As a result, engineers have used their own metrics, if at all. Some of the common metrics used include products sold and revenue, which measure the financial success of a product without recognizing the social successes or failures it might have. In this paper, we introduce a potential universal metric, the product impact metric (PIM), which quantifies the impact a product has on impoverished individuals—especially those living in developing countries. It measures social impact broadly in five dimensions: health, education, standard of living, employment quality, and security. By measuring impact multidimensionally, it captures impacts both anticipated and unanticipated, thereby providing a broader assessment of the product's total impact than with other more specific metrics. The PIM is calculated based on 18 simple field measurements of the consumer. It is inspired by the UN's Multidimensional Poverty Index (UNMPI) created by the United Nations Development Programme (UNDP). The UNMPI measures how level of poverty within a nation changes year after year, and the PIM measures how an individual's poverty level changes after being affected by an engineered product. The PIM can be used to measure social impact (using specific data from products introduced into the market) or predict social impact (using personas that represent real individuals).
A New Delayed Resonator Design Approach for Extended Operable Frequency Range
Authors: Eris Oytun , Alikoc Baran , Ergenc Ali Fuat
Published: January 2018

The operable frequency range of the delayed resonators (DR) is known to be narrow due to stability issues. This study presents a novel approach for DR design with a combined feedback strategy that consists of a delayed velocity and nondelayed position feedback to extend the operable frequency range of the DR method. The nondelayed position feedback is used to alter the natural frequency of the DR artificially while delayed velocity feedback is employed to tune the frequency of DR matching with the undesired vibrations. The proposed method also introduces an optimization parameter that provides freedom for the designer to obtain fast vibration suppression while improving the stability range of the DR. An optimization approach is also provided within the scope of this study. Theoretical findings are verified over an experiment utilizing the active suspension system of the Quanser Company.
Investigation of the Stability of a Squeak Test Apparatus Based on an Analytical and Finite Element Models
Authors: Lee Gil Jun , Kim Jay
Published: January 2018

Squeak is an unwanted, annoying noise generated by self-excited, friction-induced vibration. A unique squeak test apparatus that can generate squeak noises consistently was developed by modifying and employing a sprag-slip mechanism. Such an apparatus enables building database that accurately ranks squeak propensity of material pairs and will be highly useful for noise, vibration, and harshness (NVH) engineers and vehicle interior designers. An analytical model of the apparatus was developed to identify instability conditions that induce unstable, large-amplitude vibration, therefore squeak noises. A finite element model was established and studied in this work to refine the design of the apparatus and better understand underlying phenomena of the squeak generation. Complex eigenvalue analysis (CEA) was used to study the instability of the system and results show that the instability occurs by the coalescence of two modes, which makes the effective damping of one of the coalesced modes negative. The instability condition from the CEA shows good agreement with the results obtained from the analytical model. Furthermore, dynamic transient analysis (DTA) was performed to investigate the stability of the system and confirm the instability conditions identified from the CEA. The effects of main design parameters on the stability were investigated by DTA. The results obtained from the actual tests show that the test apparatus consistently generates unstable vibration of a very large amplitude, indicating generation of squeak noises.
Influence of Rotor Suspension Anisotropy on Oil Film Instability
Authors: Sorge Francesco
Published: January 2018

A crucial problem of turbomachinery is the oil film instability on increasing the angular speed, which is correlated with the asymmetry of the bearing stiffness matrix and resembles the hysteretic instability somehow. As a beneficial effect is exerted on the latter by the anisotropy of the support stiffness, some favorable effects have been recently found by the author also for the former, whence a systematic analysis has been undertaken. The instability thresholds may be detected by the usual conventional methods, but a detailed analysis may be carried out by closed-form procedures in the hypothesis of symmetry of the rotor-shaft-support system, which condition approaches the real working of turbomachines quite often. Altogether, the results point out an improvement of the rotor stability for low Sommerfeld numbers by softening and locking the support stiffness in the vertical and horizontal directions, respectively. Nonetheless, the partial support release on one plane implies lower instability thresholds for large Sommerfeld numbers, but this drawback may be obviated by a sort of “two-mode” stiffness management, with some vertical flexibility for heavy loads and full blocking for light loads. Otherwise, it is possible to combine the anisotropic supports with journal bearing types that offer favorable stability behavior in the range of large Sommerfeld numbers. Basing on approximate but realistic models, the present analysis elucidates the changes of the rotor-shaft unstable trend on varying the external stiffness of the supports and gives tools for a rapid calculation of the expected instability thresholds.
Derived Nodes Approach for Improving Accuracy of Machining Stability Prediction
Authors: Cao Le , Zhang Xiao-Ming , Huang Tao , Ding Han
Published: January 2018

Machining process dynamics can be described by state-space delayed differential equations (DDEs). To numerically predict the process stability, diverse piecewise polynomial interpolation is often utilized to discretize the continuous DDEs into a set of linear discrete equations. The accuracy of discrete approximation of the DDEs generally depends on how to deal with the piecewise polynomials. However, the improvement of the stability prediction accuracy cannot be always guaranteed by higher-order polynomials due to the Runge phenomenon. In this study, the piecewise polynomials with derivative-continuous at joint nodes are taken into consideration. We develop a recursive estimation of derived nodes for interpolation approximation of the state variables, so as to improve the discretization accuracy of the DDEs. Two different temporal discretization methods, i.e., second-order full-discretization and state-space temporal finite methods, are taken as demonstrations to illustrate the effectiveness of applying the proposed approach for accuracy improvement. Numerical simulations prove that the proposed approach brings a great improvement on the accuracy of the stability lobes, as well as the rate of convergence, compared to the previous recorded ones with the same order of interpolation polynomials.
Analysis of Dynamic Behavior of the Finite Elastic Metamaterial-Based Structure With Frequency-Dependent Properties
Authors: Shen X. H. , Sun C. T. , Barnhart M. V. , Huang G. L.
Published: January 2018

For practical applications of the elastic metamaterials, dynamic behavior of finite structures made of elastic metamaterials with frequency dependent properties are analyzed theoretically and numerically. First, based on a frequency-dependent mass density and Young's modulus of the effective continuum, the global dynamic response of a finite rod made of elastic metamaterials is studied. It is found that due to the variation of the effective density and Young's modulus, the natural frequency distribution of the finite structure is altered. Furthermore, based on the spectral approach, the general wave amplitude transfer function is derived before the final transmitted wave amplitude for the finite-layered metamaterial structure with decreasing density is obtained using the mathematical induction method. The analytical analysis and finite element solutions indicate that the increased transmission wave displacement amplitude and reduced stress amplitude can be controlled by the impedance mismatch of the adjacent layers of the layered structure.
A Refinement of Mindlin Plate Theory Using Simultaneous Rotary Inertia and Shear Correction Factors
Authors: Norris Andrew N.
Published: January 2018

We revisit Mindlin's theory for flexural dynamics of plates using two correction factors, one for shear and one for rotary inertia. Mindlin himself derived and considered his equations with both correction factors, but never with the two simultaneously. Here, we derive optimal values of both factors by matching the Mindlin frequency–wavenumber branches with the exact Rayleigh–Lamb dispersion relations. The thickness shear resonance frequency is obtained if the factors are proportional but otherwise arbitrary. This degree-of-freedom allows matching of the main flexural mode dispersion with the exact Lamb wave at either low or high frequency by choosing the shear correction factor as a function of Poisson's ratio. At high frequency, the shear factor takes the value found by Mindlin, while at low frequency, it assumes a new explicit form, which is recommended for flexural wave modeling.
Research on the Status of Lubricating Oil Transport in Piston Skirt-Cylinder Liner of Engine
Authors: Sun Jun , Huang Xiang , Liu Guangsheng , Zhao Xiaoyong , Miao Enming , Zhu Guixiang , Li Yunqiang
Published: January 2018

The status of the lubricating oil transport in the piston skirt-cylinder liner has important influence on the lubrication of piston assembly frictional pair, the consumption of lubricating oil, the emission, and the performance degradation of lubrication oil. In this paper, based on the model of piston secondary motion, fluid lubrication and lubricating oil flow, the status of the lubricating oil transport between the piston skirt and the cylinder liner on different engine operating condition is calculated, and the quantity of lubricating oil retained on the surface of cylinder liner is mainly analyzed when the piston skirt moves from the top dead center to the bottom dead center. The results show that the variation of the quantity of retained lubricating oil is almost same in the corresponding stroke on different engine operating condition; the quantity of retained lubricating oil is dissimilar at different moment and is equal in principle at the piston top and bottom dead center. The quantity of lubricating oil retention is dissimilar at different moment in the intake stroke or expansion stroke, but the quantity of lubricating oil retention is equal in principle at the top and bottom dead center on different engine operating condition. When the engine is on the same load condition, as the engine rotational speed increasing, the quantity of retained lubricating oil is decreased in the whole intake stroke and the middle and later parts of expansion stroke, but the quantity of retained lubricating oil is increased in the front part of expansion stroke. When the engine is on the same rotational speed condition, the quantity of retained lubricating oil increases with the increasing engine load in the front part of expansion stroke, it does not vary with the engine load in principle in the middle and later part of expansion stroke, the variation that the quantity of retained lubricating oil varies with the engine load is dissimilar in the intake stroke on different engine rotational speed condition.
A Mathematical Formula Predicts the Third Base Wobble in Codons
Authors: Bayles Brenda K. Krkosska
Published: January 2018

The 64 codons of the genetic code determine which amino acids are linked into a sequence to produce protein synthesis. Some of the codons specify the same amino acid by using only the first two letters of their codon triplet to do so, thus rendering their 3rd base irrelevant. Crick called this the wobble hypothesis, and a more complete understanding of the reading process could someday lead to a drug that can repair a misreading or to the creation of synthetic ribosomes capable of healthy protein synthesis. A step towards this goal is to apply mathematical logic to the 64 codons so that experimental results can be reproduced and to answer the specific question, how can the nucleotides in the three base positions be interpreted using mathematical code? Here it is shown that a mathematical formula derived from fluid mechanics predicts which codons in the dictionary will encode using their 3rd bases and which ones will not.
Vibration Isolation Design for Periodical Stiffened Shells by the Wave Finite Element Method
Authors: Hong Jie , He Xueqing , Zhang Dayi , Ma Yanhong
Published: January 2018

Thin plates and shells are widely used to reduce the weight in modern mechanical systems, in particularly for the aeronautic and astronautical machineries. These thin structures can result in intensive modes, and lead to the difficulty on the suppression of vibration. The excessive vibration of casing can not only lead to the failure itself but also has a significant influence on the related external pipelines and other attachments which could cause the fatigue failure for the aero-engine casings. A proper method is needed to investigate the dynamic characteristics for these casings, and to be potentially further used for the vibration isolation design.

Periodic structure has received a great deal of attentions for its band gap characteristics. Sound and other vibration can be forbidden to propagate in its band gap. With regard to the applications in aero-engines, the article provides one probable vibration isolation method for the stiffened plates and shells with high strength-to-weight ratio and with periodic configuration characteristics.

The vibration characteristics of the stiffened shell are usually difficult to be acquired, and there is neither an analytical solution for the complicated stiffeners configuration. Therefore, a Wave finite element method (FEM) based on the wave theory and finite element method, which can solve the dynamic response and band gap characteristics of casings with wide frequency band is presented. Taking the characteristics of the curvature into account, it is proposed for how to confirm the periodic boundaries of the shells. Moreover, the finite element model built by ANSYS is combined with MATLAB program, and the validity of Wave FEM is proved in shell with different boundaries including free-clamped boundary and free-free boundary. The results reveal that with the increase of stiffeners’ width, wider frequency range and larger attenuating ability appear in the vibration band gap. While with the increase of stiffeners’ thickness, neither the variety of the attenuating capability nor of the frequency range of band gaps is monotone. And the local resonance of stiffeners is obvious, the corresponding band gaps’ contribution to the whole system is little. Moreover, three typical configurations-hexagonal, square and triangular are considered. The configurations of stiffeners have distinct characteristics on the dispersion relation, if the weight problems are not taken into account, the square honeycomb is better than the others.
Doping Solar Field Heat Transfer Fluid With Nano–Particles
Authors: Abutayeh Mohammad , Addad Yacine , Alazzam Anas
Published: January 2018

A previously–developed model of a concentrating solar power plant has been modified to accommodate doping the heat transfer fluid with nano–particles. The model with its unalloyed heat transfer fluid has been validated with actual operating data beforehand. The thermo–physical properties of the heat transfer fluid were modified to account for the nano–particle doping. The nano–particle content in the heat transfer fluid was then varied to evaluate its influence on solar power generation. The model was run to simulate plant operation on four different days representing the four different seasons. As the nano–particle concentration was increased, heat losses were slightly reduced, transient warm up heat was increased, transient cool down heat was reduced, and the overall impact on power generation was trivial. Doping heat transfer fluids with nano–particles does not seem promising for solar thermal power generation from a performance perspective. Moreover, doping heat transfer fluids with nano–particles involves many other operational challenges such as sedimentation and abrasion.
Remaining Tool Life Prediction Based on Force Sensors Signal During End Milling of Stavax ESR Steel
Authors: Gebremariam Mebrahitom Asmelash , Xiang Yuan Seow , Azhari Azmir , Lemma Tamiru Alemu
Published: January 2018

This paper focuses on the prediction of the Remaining Useful Life (RUL) of a carbide insert end mill. As tool life degradation due to wear is the main limitation to machining productivity and part quality, prediction and periodic assessment of the condition of the tool is very helpful for the machining industry. The RUL prediction of tools is demonstrated based on the force sensor signal values using the Support Vector Regression (SVR) method and Neural Network (NN) techniques. End milling tests were performed on a stainless steel workpiece at constant machining parameters and the cutting force signal data was collected using force dynamometer for feature extraction and further analysis. Both the SVR and NN models were compared based on the same set of experimental data for the prediction performance. Results have shown a good agreement between the predicted and actual RUL of the tools for both models. The difference in the level of the prognostic matrices such as accuracy, precision and prediction horizon for both models was discussed.
Holographic Microwave Imaging for Breast Cancer Detection Based on Compressive Sensing
Authors: Wang Lulu , Peng Hu
Published: January 2018

Microwave imaging (MI) has been considered as an alternative way to X-ray mammography for breast cancer detection. This paper presents a compressive sensing based holographic microwave imaging (CS-HMI) approach for diagnosing of breast cancer. A numerical imaging system is developed to validate the proposed CS-HMI approach, which includes a realistic human breast phantom and measurement model. Small breast tumour can be detected in the reconstructed CS-HMI image via Split Bregman (SB) with using 10% measurement data. Simulation and experimental results show that CS-HMI has the ability to produce high quality image by using significantly less measurement data and operation time.
Coherent Structures in Turbulent Boundary Layer Flows Over a Shallow Cavity
Authors: Hammad Khaled J.
Published: January 2018

Proper Orthogonal Decomposition (POD) analysis of high-resolution Particle Image Velocimetry (PIV) measurements is used to identify the most energetic coherent structures of the turbulent flow field resulting from the interaction of a turbulent boundary layer with a shallow cavity. The PIV measurements capture the flow structure and turbulence, upstream, over, and downstream of a shallow open cavity. Two sets of PIV measurements corresponding to a turbulent incoming boundary layer and a cavity length-to-depth ratio of four are used. The cavity depth based Reynolds numbers are 21,000 and 42,000. The first six POD modes are found to contain a substantial percentage of the overall turbulent energy, approximately 45.2% and 45.7% for Reynolds numbers of 21,000 and 42,000, respectively. The overall spatial and modal energy content distribution are almost identical for both Reynolds numbers. The spatial flow characteristics of POD modes 1–6 reveal the existence of vortical structures, developing in the mixing region, that grow in size as they approach the trailing edge of the cavity. POD mode number one, containing approximately 20% of the overall turbulent energy, represents non-impinging vortices interaction with the cavity trailing edge, while POD modes 2–6 capture various stages of the impinging vortices type of interaction.
A Numerical and Experimental Study of Laminar Unsteady Lid-Driven Cavity Flows
Authors: Akyuzlu K. M.
Published: January 2018

An experimental and numerical study was conducted to study unsteady lid-driven cavity flows. More specifically, the development of the circulation patterns inside a square cavity due to the movement of a rigid impermeable lid at constant velocity was observed experimentally and predicted numerically by CFD codes.

Particle Image Velocimeter (PIV) technique was used to determine the flow field as it develops from stagnation to steady state inside a one inch (25.4 mm) square cavity driven by an impermeable lid. To avoid the three dimensional effects on the primary vortex, the depth of the cavity is taken to be 5 inches (127 mm). Working fluid is water and it is seeded with hallow glass spheres with 10 microns diameter. Experimental study was conducted for different lid velocities corresponding to Reynolds numbers for laminar to intermittent turbulence. The numerical study was carried out using commercial and in-house CFD codes for the steady state case, and using a commercial CFD code for the unsteady case. The predictions of unsteady flow field inside the two-dimensional square cavity were made using these codes which employ second order accurate (temporally and spatially) implicit numerical schemes. A time and mesh independence study was carried out to determine the optimum mesh size and time increment for the unsteady case study. Comparisons of the numerically predicted and experimentally measured velocity fields are made for steady and unsteady cases. The results indicate that the numerical predictions capture the characteristics of the circulation inside the cavity reasonably well however the magnitude of the velocities are underestimated.
Electrostatic Suppression of the Leidenfrost State Using AC Voltages
Authors: Ozkan Onur , Bahadur Vaibhav
Published: January 2018

The Leidenfrost effect is a well-known phenomenon in boiling, wherein a vapor layer forms between a hot surface and the liquid, thereby degrading heat transfer. Electrowetting (EW) can be used to fundamentally eliminate the Leidenfrost state by electrostatically attracting the liquid towards the surface; the resulting enhanced wetting substantially increases heat transfer. This work presents preliminary results of a study to understand the influence of AC voltages on Leidenfrost state suppression; prior studies have only utilized DC voltages. It is seen that the AC frequency is a very important determinant of the effectiveness of Leidenfrost state suppression. The electrostatic force which attracts the liquid to the surface decreases with increasing AC frequency; this reduces the extent of suppression. This effect is measured and studied by high speed visualization of suppression as well as measurements of the evaporation/boiling rate under AC EW conditions. It is observed that the instabilities (resulting in suppression) at the vapor-liquid interface reduce at higher frequency. The evaporation rate also reduces with AC frequency, as less heat is picked up by the droplet. It is noted that the evaporation rate has lower and upper bounds, which correspond to the evaporation rates without any EW and with DC voltage, respectively. Overall, this work highlights the importance of the AC frequency as a tool to control the extent of suppression and the boiling heat transfer rate.
Rocket-Augmented Two Stage Runway Based Space Access Architecture
Authors: Komerath Narayanan
Published: January 2018

A runway-based space access system concept based on two stages to orbit is further refined. Routine access to Space with large payloads is essential for Space infrastructure projects such as solar power stations. The aim is to develop a reference architecture to enable cost estimation for a large reusable fleet. Prior work established that a 25000 kg payload could be delivered to low earth orbit starting with takeoff from a runway using a vehicle with the parameters of today’s large airliners. Hydrogen-fueled high-bypass turbofans provide efficient subsonic climb while oxygen is liquefied and stored. The second stage is launched at transonic speed at 18 kilometers altitude, followed by aerodynamic flight with ramjet, SCRAMjet and then rocket propulsion to orbit. A new feature is a brief rocket burn to fill the transonic ramjet performance gap, followed by ramjet-powered supersonic acceleration and climb. Beyond 60 km, SCRAMJET acceleration reaches the von Karman limit of 100km at Mach 8, beyond which rocket propulsion takes the craft to orbit. A refined initial mass estimation process allows the design to close swiftly, showing that payload capacity can be increased in future iterations with the same carrier aircraft parameters.
Performance Enhancement in Unconventional Radiator
Authors: Raza Hammad , Porangada Suraj Somanna , Islam Wahidul , Naviwala Mohammed , Khan Jobaidur Rahman
Published: January 2018

A number of cars are found to have an unconventional radiator. The radiator is placed at the back of the car instead of front, for which the radiator does not get the incoming airflow to cool the engine down and the engine gets overheated very easily. In order to deal with this problem, a channel has mounted at the top of the vehicle to navigate incoming air flow and direct it through the radiator to cool down the engine. The channel that is provided has three cases, which will indicate the different way of studying this problem. Both steady and transient state analysis has been performed. Each case has its own characteristics. For example, a longer channel creates little circulation but more axial flow towards the radiator, while shorter channel creates smooth but less axial flow towards the radiator. All these cases in the steady state have the same domain and will have similar inlet variables like velocity, shape, size, and position. However, the domain geometry was slightly changed for transient state scenario.

At steady state simulation, most of the circulation were shown in the left-mid plane especially in longer channels. On the other hand, the transient state gives more uniform flow distribution. For longer channels in transient case, the flow is symmetric and smooth. The results were all made and developed in ANSYS for the final design where the data were simulated.
Addressing Uncertainty in Constitutive Model Forms and Parameters for FE Models of the Human Head Subjected to Blast Loading
Authors: Brewick Patrick , Teferra Kirubel
Published: January 2018

This work lies within an overall effort to improve, as well as quantify, the uncertainty of traumatic brain injury (TBI) prediction for blast loading. Detailed finite element (FE) modeling of the human head currently provides the only viable means to quantify the mechanical response within the brain during a blast loading event. Unfortunately, the exact linkages between loading patterns, tissue mechanical response, and injury/physiological effects are still quite unknown; however, the exceedance of specified threshold values based on direct and derived measures of stress, strain, pressure, and acceleration within the brain have been shown to be useful injury criteria. The utility of these threshold values is somewhat mitigated by the fact that preliminary parametric studies focusing on varying head morphology and the material properties of FE head model components have shown significant variation in the predicted injury response, indicating that the exact relationship between model geometry, material properties, and mechanics-based injury response metrics has not yet been established.

Identifying an appropriate constitutive model form and optimal parameter values for biological tissues is an enormous challenge hindered by large epistemic uncertainties. Available experimental data sets frequently offer valuable but limited information due to the many vagaries associated with the testing of biomaterials, such as testing on different species, e.g., porcine and bovine specimens, testing with inapplicable strain rates, and having too little data. The parameters of hyperelastic, hyper-viscoelastic, and viscoelastic constitutive models, which are commonly utilized for modeling these biological tissues, can be fit to an aggregation of experimental data through a constrained optimization formulation. Specifically, this study considers fitting data from biomaterials to Ogden’s model of hyperelasticity. The goodness of fit of the optimization is limited by the appropriateness of the model forms as well as limited, and at times contradictory, data. In order to properly account for these uncertainties, a Bayesian approach is adopted for model calibration and posterior distributions are therefore produced for each model parameter.
Flow Characteristics of a Narrow Rectangular Channel Equipped With a Flapping Flag
Authors: Gallegos Ralph Kristoffer B. , Sharma Rajnish N.
Published: January 2018

Recently, the use of flapping plates or ‘flags’ as vortex generators has gained attention for its potential application in heat transfer enhancement in channels. The motion of the flag generates additional turbulence which leads to enhanced heat transfer. However, very few reports deal with the turbulence characteristics inside a channel with flag vortex generators. This paper presents some flow turbulence properties experimentally measured behind a flapping flag. Using multi-hole pressure (cobra) probes, the flow properties behind a flag (M* = 0.42) were measured in a rectangular channel (aspect ratio, α = 1/3) at four levels of flow Reynolds number (Redh = 11.5k–19.7k). Results show that the spectral properties of the flow parameters are closely dependent on the flag oscillation properties. Depending on streamwise location and Redh, measurements reveal that the flag can generate as high as 20% turbulence intensity in the channel centerline, almost six times that of a bare channel at the same Redh. In addition, a streamwise location has been identified where the flag’s oscillation no longer influences the spectral characteristics of the flow. The insights gained from this study may serve as a basis for the design and analysis of systems using flags as turbulence enhancers.
Autonomous Platform Collecting the Vegetation in Excess From Natural Reservations Lakes Used As a Future Biomass Resource
Authors: Radulescu Victorita
Published: January 2018

In Romania, near the Black Sea are two Natural Reservations lakes with salt water, Techirghiol, and Mangalia nowadays confronted with new environmental issues. Lake never freezes. Under these conditions, there are always birds in transit or in wintering; some of them protected species as endangered. There are no known or available solutions at present that can be used here, without disturbing the biological balance. This paper presents a prototype, patent pending in Romania, which has achieved significant results in protection of the natural environment. The prototype is an autonomous pilot station, placed on a mobile pontoon, powered by photovoltaic panels. It can collect and partially dry the aquatic vegetation developed in excess due to eutrophication. The harvested vegetation is used as the biomass resource to warm the Research Centre on shore, the greenhouse for the protected plant species and the poultry incubator. The prototype now is implemented in Techirghiol Lake as to diminish the local environmental problems: the massive mass of vegetation, the invasive species that appeared, as the invertebrates, the interference scallops, and the predator fish. Due to the permanent decreasing the number of the specific fish, all bird colonies are affected. The proposed solution is innovative, perfect ecological and energetic independent. The mobile pontoon is commanded from distance. The solar panels ensure the pontoon movement and the supply of the collecting, compacting, and partially drying the vegetation. The detailed functioning of the prototype is further detailed presented. The main advantage of this solution is that the vegetation can be collected during the entire period of vegetation without disturbing the biologic environmental, nests period of construction, laying eggs, rearing birds, etc. A second major advantage is that the extracted vegetation can be consumed immediately and integrally into a biomass power plant. The third advantage of this technology is that the platform is placed on a mobile pontoon energetically independent, entirely automated and with a constant adaptation of the operating parameters in accordance with climatic conditions. This innovative solution is accordance to the Romanian reply for EU Council Directives, UE EUCO 75/13 CO EUR 7 signed in Brussels at 22/05/2013, referring to the promotion of the new solutions based on utilization of renewable technology with environmental effects. The prototype has a multi- and a cross-disciplinary character due to the main components. It represents a powerful applicative research requested and co-financed by the National Authorities and the private sector, as to solve this problem appeared into these Natural Reservations.
Critical Factors That Impact Consistency of Fit and Finish at the Rear Fascia Cutline of Vehicles
Authors: Mansour James , Jawad Badih A. , Abro Sabah , Liu Liping , Fernandez Vernon , Tibbenham Jeff
Published: January 2018

A vehicle’s exterior fit and finish, in general, is the first part to attract customers. For this reason, customers consider the J.D. Power report which classifies all vehicles based on different criteria. One of the criteria is the vehicle exterior fit and finish which is measured by two important factors called Flush and Gap. Automotive exterior engineers have been motivated in the past few years to increase their focus on optimizing the vehicle’s exterior panels split lines quality and minimizing variation in fit and finish to address customer and market quality standards.

Design engineers focus on controlling the deviation from nominal build objective and minimizing it. This study focuses on addressing the contributed factors that impact the quality of fit and finish. These critical factors resulted from the design process, product process and from the assembly process. An empirical analysis was used to minimize the fit and finish deviation.

Models that accurately describe the response values by experiments helped identify the most critical factors, and an analytical model and Response Surface Methodology (RSM) were used to optimize the acceptable values on these factors. Early results showed that some of these factors are critical for improving the quality of the fascia cutline fit and finish by obtaining more consistent gap and flush along the rear fascia cutline as well as reducing the offset issue.

The results of this study identified 17 critical factors which were split between controls and can be dialed to change the magnitude of the results and noises which have less effect on changing the results. Also, the 17 factors were separated into factors that affect Gap “α” or factors that affect flush “β” or both. Eight factors were selected based on production experience and based on their levels. Empirical analysis was conducted to generate regression models for both α & β. The selected factors were tested for their effect; also, the study took in consideration of different combined effect of these factors. Optimization with these factors were conducted for α & β. The results show that α can approach ±0.5 mm and β can approach ± 1 mm. The conclusion is that the consistency of α & β along the fascia to bodyside panel cutline (defined as ϴ) will be maximum when both α & β are minimum. The ultimate goal is to reach the stretched target which means zero mm gap and zero mm flush.
Crashworthiness Performance of Carbon Fiber Composite (CFC) Vehicle Front Bumper Crush Can (FBCC) Assemblies Subjected to High Speed 40% Offset Frontal Impact
Authors: Dixit Y. , Begeman P. , Dhaliwal G. S. , Newaz G. , Board D. , Chen Y. , Faruque O.
Published: January 2018

This research article presents the crashworthiness response of carbon fiber composite front bumper crush can (FBCC) assembly subjected to 40% offset frontal impact loading. Automobile manufacturers continue to strive for overall vehicle weight reduction while maintaining or enhancing safety performance. Therefore, the physical testing of lightweight materials becomes extremely important under a crash scenario in order to apply them to automotive structures to reduce the overall weight of the vehicle. In this study carbon fiber/epoxy lightweight composite material is chosen to develop frontal bumper beam crush can assemblies. Due to lack of available studies on carbon fiber composite FBCCs assemblies under frontal offset crash scenario, a new component-level experimental study is conducted in order to develop data that will provide assistance to CAE models for better correlation. A sled-on-sled testing method was utilized to perform tests in this study. 40 % offset frontal tests on FBCC structures were conducted by utilizing three high-speed cameras (HSCs), several accelerometers and load wall.

Impact histories i.e. crash pulse, force-time history, force-displacement, impact characteristics and deformation patterns from all FBCC tests were consistent. The standard deviation and coefficient of variance for the energy absorbed were very low suggesting the repeatability of the 40% offset tests. Excellent correlation was achieved between video tracking and accelerometers results for time histories of displacement and velocity. Post-impact photographs showed the progressive crushing of composite crush cans, bumper beam/crush can adhesive joint failure located on unimpacted side and breakage of the bumper beam due to the production of shear stresses as it is stretched due to its curvature after hitting the sled.
Performance Tuning of an IC Engine Based on Pressure Wave Propagation With a Continuously Variable Exhaust Runner Length and Exhaust Valve Timing System
Authors: Gajula V. , Bari S.
Published: January 2018

The momentum of exhaust gas flowing out of the valve creates a pressure wave which can have a positive effect on the evacuation of gases. This concept is known as wave tuning, utilizes the sub-atmospheric pressure waves in the runner to evacuate more exhaust gases. When tuned precisely by varying length and/or exhaust valve timing in such a way that the wave returns in accordance to the exhaust valve opening, it creates a scavenging effect and this improves the engine performance. In this research both exhaust runner length and valve duration have been changed to arrive the sub-atmospheric wave at exhaust valve to improve the performance of the engine using Ricardo WAVE software. It was found that varying the exhaust valve timing managed to improve the torque by 1–3% at different rpm. However, varying both length and timing improved the toque 7–10% at lower speed and 3–6% at higher rpm.
Design, Development and Testing of Water-Lubricated Ceramic Journal Bearing
Authors: Zha Jun , Wang Jianlei , Liu Kejia , Chen Yaolong
Published: January 2018

Strong shear force developed in the fluid film as the water-lubricated hybrid bearing operates at high speeds. Thus the phenomena of shaft expanding outward and bearing contracting inward happened due to the increasing temperature of the fluid film caused by the friction heat. So the bearing clearance decreases on account of the thermal deformation of the shaft and the bearing. Seriously, there will be a risk of seizure accident when the speed gets higher. Friction heat may be weakened by adopting low viscosity lubricant and thermal deformation may be reduced by adopting low expansion coefficient materials. Such as the ceramic’s expansion coefficient is 3–5 times smaller than that of typical journal bearing material like tin bronze. Thus, a ceramic journal bearing was developed in this paper to weaken the thermal influence on the bearing clearance. For improving the temperature rise of the journal bearing, a water-lubricated ceramic hydrodynamic-hydrostatic hybrid bearing test rig was designed firstly. Considering expansion coefficient and thermal conductivity effects, the simulation method was used to study the variation of bearing clearance with the speed and the original bearing clearance. Then, the water-lubricated ceramic hydrodynamic-hydrostatic hybrid bearing test rig was developed to verify the temperature characteristics at different speeds. Results indicate that the relative error of the tested temperature results and simulation results was below 10% at different speeds. Lastly, the evolution of bearing clearance with speed and the original bearing clearance was studied through FEM. The advantages of ceramic material were more obvious with the increase of the rotation speed when exceeds 8000rpm.
Theoretical Analysis of a Novel Planetary Gear Type Inerter for the Torsional Vibration Suppression Capability of Automotive Drive Train System
Authors: Ogawa Aki , Adachi Kazuhiko
Published: January 2018

This study aims at proposing a novel planetary gear type inerter which has a capability of regulating the resonance and anti-resonance characteristics of the torsional vibration system, for example, reducing resonance and anti-resonance frequencies, generating new anti-resonance, etc. The ideal inerter is introduced by Smith (2002) as “a mechanical two-terminal, one-port device with the property that the equal and opposite force applied at the nodes is proportional to the relative acceleration between the nodes[1].” The proposed inerter consists of a planetary gear unit. The governing equation of the proposed inerter is derived as matrix formula. According to the theoretical analysis of the formulation in the frequency domain via Laplace transformation, the proposed inerter has the capability to tune the vibration characteristics of the torsional vibration system. Under the simplification assumptions of the system parameters, the numerical simulation results successfully demonstrate the vibration characteristics tuning capability of the proposed inerter.