bluuebunny/crossref_metadata_2025 huggingface dataset:
End‐to‐end electronic transfusion management in hospital practice
Authors: Murphy M. F.
Published: June 2012

Background  Errors occur at all stages of the hospital transfusion process and the resulting morbidity and mortality are well documented. Recent initiatives in the UK and elsewhere to reduce transfusion errors have focussed on implementing recommended manual procedures for good practice, but have only been partially effective.

Aims  Our approach was to ‘re‐engineer’ bedside and laboratory transfusion procedures.

Materials and Methods  We implemented barcode patient identification, bedside handheld computers and electronically controlled blood fridges to simplify transfusion procedures and improve practice.

Results  There was an improvement from 11.8% to 100% of staff following the process for correct pre‐transfusion bedside patient identification; no ABO incompatible red cell transfusions in 5 years; a reduction in wrong blood component transfused events from 1 in 27,523 to 1 in 67,935; reduced nursing (one nurse rather than 2 and half the time to administer blood) and laboratory workload; and more rapid delivery of urgently required red cell units to patients (from a median of 18 minutes to 45 seconds). The electronic system provided a simple mechanism for compliance with UK/EU regulatory requirements for the traceability of blood, and the documentation of transfusion and training. Feedback from both staff and patients was positive.

Discussion  The project was taken through pilot stages between 2001 and 2006 through to its full implementation across the acute hospitals in Oxfordshire in 2006/07. Our group wrote a national specification for the electronic transfusion process, but the implementation elsewhere in the UK has been slow. There is the potential to introduce an additional module into the electronic transfusion process to provide ‘decision support’ for doctors ordering blood to minimise inappropriate use of blood as part of a patient blood management programme, and use the same ‘end‐to‐end electronic’ approach for other clinical procedures such as drug administration.

Conclusion  The implementation of a hospital electronic transfusion management system was shown to provide improvement in transfusion practice and in the efficiency of the service.
What methods and process flow can assist in alloantibody identification
Authors: Poole J.
Published: June 2012

When a positive antibody screen is encountered there are many pathways that can be followed for antibody identification and every laboratory should have a policy outlining its standard procedures. It is important that a systematic approach is taken, both to assigning a specificity (ies) and to excluding all clinically significant antibodies that the patient is capable of making. Several reagent red cell panels may be needed to identify some combinations of antibodies. It is useful to know the ethnic background of the patient because some combinations of phenotypes are found almost exclusively in certain populations. Identification of alloantibody specificity is a process undertaken to enable informed decisions to be made regarding suitable blood for transfusion to a patient. It is important to realize that not all antibodies are clinically significant and antigen‐negative blood is not always needed. When complex mixtures or antibodies to high incidence antigens are present, resolution can be difficult and time‐consuming, thus causing a delay in patient care.
Introduction of programs for voluntary blood donation in Central America
Authors: Cruz J. R.
Published: June 2012

National proportions of voluntary donation varied from 4.3 to 87.1% in 2009. Average number of units processed per center per year predicted voluntary donation.
Blood donation patterns and challenges in Southern Africa
Authors: Reddy R.
Published: June 2012

Introduction:  Developing countries face significant challenges in collecting sufficient blood to meet the demands from patients. Southern African countries have implemented many initiatives to recruit and retain sufficient voluntary blood donors and the success has been varied in different countries.

Objective:  To analyse blood donor patterns and challenges in the 14 Southern African countries and assess progress made in attaining a 100% voluntary donor base as well as collecting sufficient blood as per the WHO recommendations for developing countries.

Results:  A literature review showed that between 2004 and 2008 very little progress has been made with regard to improving the number of blood donations per 1000 population and increasing the number of voluntary non‐remunerated blood donors. When factors such as age, disease burden and poverty are factored in, the donor potential in these countries is low.

Discussion:  Collecting sufficient, safe blood from voluntary blood donors continues to be a major challenge for many developing countries and co‐ordinated efforts, with assistance from external organizations, is required.
TTID risk in the Latin America and Caribbean: recommendations to improve safety
Authors: Rojo J. , Arroyo A.
Published: June 2012

Transfusion‐Transmitted Diseases (TTD) have been a persistent risk since the onset of transfusion medicine. In Latin America and the Caribbean countries (LACC), prevention of TTD requires special and different care in comparison with the in United States and European countries, due to the still persistent high prevalence of replacement donors, specific geographic location, topography, and climate, genetic and cultural and socio‐economic status of the population. These factors result in different distribution patterns of the infections, which together with the migration have changed the donor profile. According to the Pan American Health Organization (PAHO) reports, the screening of HIV, HBV, HCV and T. pallidum has increased in LACC since 2005, significantly reducing the risk of transmission. However these results have not yet reached the established aim in 1998, of analyzing 100% of blood units for these pathogens.

The strategies recommended for the LACC should be based on the following points: a) the establishment of national blood transfusion services, b) blood collection from volunteer donors, c) high quality monitoring of TTD and emerging transfusion‐transmitted infections (ETTI) in all blood units, d) implementation of effective quality assurance systems and e) the rational use of blood components and alternatives to transfusion.
Quality management of blood collection
Authors: Strengers P. F. W.
Published: June 2012

The objective of the quality management in the blood transfusion service is the continuous improvement of the quality of the processes and the products related to the blood donation of the blood donors, the production of the blood components and the transfusion of the blood products to the recipients. The efficacy, the safety and the efficiency of the blood transfusion processes requires that the personnel is educated and trained, that processes are described in standard operating procedures and that these procedures are followed up. When the concept of quality and the improvement of quality is in the mind of all working in the field of blood transfusion medicine, the quality of the blood transfusion service will go upwards, the donors will feel themselves respectfully treated and rewarded, the blood products will become more efficacious and safe, and the patients will receive the best products available.

Quality management of blood collection implies the processes on donor recruitment, donor handling and donor vigilance, and the process of donation and screening. For all processes in blood collection, quality indicators should be defined and these data should be monitored, collated, analysed, reported and used in order to improve the quality of the processes.
Clinical effects of transfusing older red cell concentrates: an updated overview
Authors: van de Watering L. M. G.
Published: June 2012

The literature on possible effects of prolonged storage of red cells is growing fast. Recent studies still come up with conflicting results. This review describes some of the underlying mechanisms which may explain the opposing results from the different studies.
Apheresis versus whole‐blood‐derived platelets: pros and cons
Authors: van der Meer P.F.
Published: June 2012

Platelet concentrates for prophylactic or therapeutic treatment of patients can be isolated from whole blood using the platelet‐rich plasma‐method or the buffy coat‐method on one hand, or can be collected by apheresis with return of unwanted blood cells to the donor on the other hand. A number of variables among the methods, including the anticoagulant, centrifugation and processing after collection, and pre‐ or post storage pooling, affect storage characteristics of platelets. Data suggest, however, that most differences balance out, both based on in vitro studies, and on recovery and survival studies. A marginal difference in corrected count increment in favor of apheresis platelets was observed, but the practical consequence is likely to be small. The need for pooling of whole‐blood‐derived platelet concentrates increases donor exposure, and thereby potentially increases the risks associated with transfusion of whole‐blood‐derived platelet concentrates. Indeed, risk of viral and variant Creutzfeldt‐Jakob disease transmission is at least two‐fold higher for whole‐blood‐derived platelet concentrates, but allo immunization rates, acute reaction rates, and transfusion related acute lung injury rates are not different. Apheresis donation procedures have fewer adverse events. The various benefits and disadvantages of the methods have to be balanced when choosing a preferred way of platelet collection.
Noninvasive prenatal screening for RHD: the Stockholm study
Authors: Wikman A. T. , Tiblad E. , Westgren M.
Published: June 2012

The non‐invasive technique to determine fetal RHD status opens the opportunity to change the antenatal screening and Rh‐prophylaxis programs. During the period September 2009 to December 2011, we performed a study in the Stockholm area with approximately 27000 pregnancies per year. The study included routine cell free fetal DNA (cffDNA) RHD genotyping in early pregnancy followed by targeted RAADP in gestational week 29 to all RhD negative pregnant women carrying an RHD positive fetus. The new approach in our strategy, compared to previous studies, was that fetal RHD screening was done in early pregnancy at the first antenatal visit and based on a single‐exon 4 assay. The implementation of this new screening program in a routine clinical setting is described. The final results of the study are still under analysis. The conclusion until now is that fetal RHD screening in early pregnancy is feasible and accurate with a high sensitivity and specificity, provided samples before gestational week eight were excluded.
Management of acquired coagulopathies in ITU
Authors: Thomas D.
Published: June 2012

Acquiured coagulopathies are releatively frequent in an intensive care setting. In the majority of situations knowledge of the presenting disease process can help address treatment strategies.

Often laborotary tests are either unhelpful or due to delay in reporting the results of such tests, the urgent situation has become worse with time and the clinical scenario will have changed.

There is also a possibility when dealing with unstable patients that anxiety on behalf of the clinician may result in unwarrented use of blood components.

A logical and calm approach supported by point of care testing can result in more appropriate use of blood components.
A nation‐wide fetal RHD screening programme for targeted antenatal and postnatal anti‐D
Authors: de Haas M. , van der Ploeg C. P. B. , Scheffer P. G. , Verlinden D. A. , Hirschberg H. , Abbink F. , van der Schoot C. E.
Published: June 2012

In the Netherlands, since 1 July 2011, both antenatal anti‐D immunoprophylaxis (1000 IU in the 30th week of gestation) and postnatal prophylaxis (1000 IU) is administered to only those women for whom a fetal RHD typing, performed in week 27 of pregnancy, predicts the presence of a D‐positive child. The fetal RHD screening is part of the antenatal Screening Programme for Infectious diseases and Erythrocyte immunisation (PSIE), offered to all pregnant women early in pregnancy at their first antenatal visit, preferably before 12 weeks of gestation.

Currently, the compliance to the fetal RHD screening programme and the performance of the fetal RHD typing test is evaluated in a nation‐wide study. At the start of the programme, it was determined that the number of false negative test results should be below 0·25%.

In the first seven months after introduction of the fetal RHD screening programme, the number of false‐negative results was below the critical threshold and the number of false positives around 1·1%. The compliance to the programme was in this period >95%.

Our first analysis confirms that, in a centralised setting, it is possible to guide both antenatal and postnatal anti‐D immunoprophylaxis by fetal RHD screening in maternal blood obtained at 27 week of gestation. The current analysis, however, is based on the cord blood samples received by Sanquin only. A longer period of nation‐wide evaluation of the fetal RHD screening programme, including all (also locally typed) cord blood serology results obtained in a one‐year time period, will provide insight in the robustness of the fetal RHD screening programme.
Blood transfusion and the social contract
Authors: Franklin I. M.
Published: June 2012

Aims  To present a rational approach to delivering a safe and effective blood supply.

Methods  Literature searching, reflective learning, peer group discussion.

Results  To provide a consistent blood supply system, there is much to learn from the rigour of philosophy. The organic development of blood safety practices has led to some inconsistencies. It is essential to consider all of those involved in the process, including donors and recipients but particularly those who may be damaged by, for example, a transfusion‐transmitted infection.

Conclusion  Current practices, at least in some countries, have evolved and use a mixture of philosophical approaches. A new way is recommended.
Platelets have a role as immune cells
Authors: Semple J. W.
Published: June 2012

Abstract:  Platelets are the primary cellular mediators of hemostasis and this function intimately acquaints them with a variety of inflammatory processes. For example, when aggregated on damaged vessel walls, activated platelets can secrete and express many pro‐ and anti‐inflammatory molecules that attract and capture circulating leukocytes and focus them on inflamed tissue. Platelets secrete several chemokines and cytokines that affect local innate immune responses by, for example, attracting neutrophils to sites of inflammation. In addition, platelets may directly regulate adaptive humoral immune responses via their expression and secretion of CD40/CD40L molecules. These studies have also suggested that platelets represent an important linkage between inflammation and thrombosis. Platelets also avidly bind to microorganisms and do so by expression of Toll‐like receptors. It appears that platelets may act as circulating sentinel cells that first encounter blood borne infectious products for presentation and activation of innate immune responses. This lecture will highlight several attributes of platelets that draw them into the realm of immunity and will discuss how platelets may be responsible for directly and indirectly controlling immune functions.
Characteristics of achalasia subtypes in untreated Chinese patients: A high‐resolution manometry study
Authors: Min Min , Peng Li Hua , Yang Yun Sheng , Hou Xiao Hua , Guo Rong Bin , Wang Wei Feng , Sun Gang , Wang Xiao Xiao
Published: June 2012

Objective

To evaluate and compare the clinical characteristics, manometric results and treatment outcomes of different subtypes of achalasia in untreated Chinese patients using high‐resolution esophageal manometry.

Methods

A total of 75 achalasia patients and 34 healthy controls were enrolled in the study, and three achalasia subtypes were determined based on the Chicago classification. Clinical characteristics, manometric and treatment outcomes were compared.

Results

In all, 25 patients were classified as type I, 46 as type II and 4 as type III. The mean overall length of lower esophageal sphincter (LES) in type III was significantly longer than those in the controls and type I patients (P < 0.05), and abdominal LES length was significantly longer in type III than those in controls, type I and type II patients. All subtypes of achalasia had higher resting and residual LES pressures than those found in healthy controls (P < 0.05). Resting upper esophageal sphincter (UES) pressure in type III patients was significantly lower than those in healthy controls and type I patients, whereas types I and II patients had higher residual UES pressures compared with healthy controls (P < 0.05). Type II patients had a better response to the treatment than type I and III patients.

Conclusions

Type II is more common in untreated Chinese achalasia patients, and type II patients had better treatment outcomes than other types of patients. Large‐sample multicenter trials are necessary in the future.
Central/Peripheral Fat Mass Ratio Is Associated With Increased Risk of Hypertension in HIV‐Infected Patients
Authors: Freitas Paula , Carvalho Davide , Santos Ana Cristina , Madureira António José , Xerinda Sandra , Martinez Esteban , Pereira Jorge , Sarmento António , Medina José Luís
Published: June 2012

J Clin Hypertens (Greenwich). 2012; 14:593–600. © 2012 Wiley Periodicals, Inc.

The data on the risk of hypertension in human immunodeficiency virus (HIV)–infected patients, particularly in those with lipodystrophy, are controversial. The authors assessed the impact of lipodystrophy on hypertension in a cohort of HIV‐infected adults receiving combination antiretroviral therapy. This was a cross‐sectional study in which lipodystrophy (clinically and fat mass ratio [FMR]–defined), blood pressure, and body composition (dual‐energy x‐ray absorptiometry and computed tomography) were evaluated in 368 HIV adults. The prevalence of hypertension in HIV patients with or without clinically or FMR‐defined lipodystrophy was similar (with clinical lipodystrophy 35.3% vs without 32.9%, not significant; with FMR lipodystrophy 41.7% vs without 32.2%, not significant). When HIV‐infected patients were classified into 4 categories of fat distribution (based on the presence or absence of lipoatrophy and abdominal prominence), isolated lipoatrophy was not significantly associated with hypertension, but patients with isolated central fat accumulation and mixed forms of lipodystrophy had a significantly higher prevalence of hypertension. Hypertensive HIV patients had significantly higher total fat, central, and central/peripheral fat mass ratio than normotensive ones. After adjustment for age, sex, smoking, and body mass index, hypertension remains significantly associated with central/peripheral fat mass ratio (odds ratio, 1.258; 95% confidence interval, 1.008–1.569). Hypertension was not more prevalent in lipodystrophic HIV‐infected patients, but was significantly associated with central/peripheral fat mass ratio.
Comparison of Methods Analyzing Bifurcation and Hunting of Complex Rail Vehicle Models
Authors: Polach Oldrich , Kaiser Ingo
Published: June 2012

The stability assessment is an important task in the mechanical design of railway vehicles. For a detailed model of a railway passenger coach, the hunting behavior depending on the running speed, on wheel-rail contact conditions, and on different model configurations is analyzed using two different methods: The path-following method based on a direct computation of limit cycles enables an automatic computation. However, due to the direct computation, which exploits the periodicity of the solution, this method is restricted to strictly periodic behavior. In the brute-force method, an initial disturbance limited to a certain time interval is applied to the model. This method allows the analysis of the behavior independently from the type of the solution, but requires manual intervention. The comparison of the results obtained with both methods shows a good agreement and thereby the reliability of the results and the methods.
Aeroelastic Limit Cycles as a Small Scale Energy Source
Authors: Dunnmon Jared A. , Stanton Samuel C. , Mann Brian P. , Dowell Earl H.
Published: June 2012

Nonlinear limit cycle oscillations of an aeroelastic energy harvester are exploited for enhanced piezoelectric power generation from aerodynamic flows. Specifically, a flexible beam with piezoelectric laminates is excited by a uniform axial flow field in a manner analogous to a flapping flag such that the system delivers power to an electrical impedance load. Fluid-structure interaction is modeled by augmenting a system of nonlinear equations for an electroelastic beam with a discretized vortex-lattice potential flow model. Experimental results from a prototype aeroelastic energy harvester are also presented. Root mean square electrical power on the order of 2.5 mW was delivered below the flutter boundary of the test apparatus at a comparatively low wind speed of 27 m/s and a chord normalized limit cycle amplitude of 0.33. Moreover, subcritical limit cycles with chord normalized amplitudes of up to 0.46 were observed. Calculations indicate that the system tested here was able to access over 17% of the flow energy to which it was exposed. Methods for designing aeroelastic energy harvesters by exploiting nonlinear aeroelastic phenomena and potential improvements to existing relevant aerodynamic models are also discussed.
GPU-Based Haptic Simulator for Dental Bone Drilling
Authors: Zheng Fei , Lu WenFeng , Wong Yoke San , Foong Kelvin Weng Chiong
Published: June 2012

Dental bone drilling is an inexact and often a blind art. Dentist risks damaging the invisible tooth roots, nerves and critical dental structures like mandibular canal and maxillary sinus. This paper presents a haptics-based jawbone drilling simulator for novice surgeons. Through the real-time training of tactile sensations based on patient-specific data, improved outcomes and faster procedures can be provided. Previously developed drilling simulators usually adopt penalty-based contact force models and often consider only spherical-shaped drill bits for simplicity and computational efficiency. In contrast, our simulator is equipped with a more precise force model, adapted from the Voxmap-PointShell (VPS) method to capture the essential features of the drilling procedure. In addition, the proposed force model can accommodate various shapes of drill bits. To achieve better anatomical accuracy, our oral model has been reconstructed from Cone Beam CT, using voxel-based method. To enhance the real-time response, the parallel computing power of Graphics Processing Units is exploited through extra efforts for data structure design, algorithms parallelization, and graphic memory utilization. Preliminary results show that the developed system can produce appropriate force feedback at different tissue layers.
Identification of the Structural Modes of High Performance Bicycles in the Perspective of Wobble Control
Authors: Doria Alberto , Formentini Matteo
Published: June 2012

Most of researches in the field of bicycle dynamics deal with auto-stabilization and rider control by means of steer-torque and lean-torque. Bicycle models composed by rigid bodies with thin wheels making point contact with the road and rolling without any slip are suited for carrying out these studies. Numerical analysis of stability by means of these models leads to the capsize, castering and weave modes, which make it possible to understand many aspects of bicycle dynamics. However, some high performance bicycles at high speed show dangerous wobble oscillations. Cyclists’ experience and recent researches highlight that wobble phenomena are related both to tire properties and to fork and frame compliance. Since structural compliance in dynamic conditions generates vibrations, this paper focuses on the study of structural vibrations of high performance bicycles with the modal analysis approach. To isolate the effects of frame and fork compliance, four particular bicycles are considered, they are built assembling a pair of wheels, two forks (fork A and B) with the same shape but different structures and materials and two frames (frame A and B) with the same shape but different structures. Preliminary road tests showed that bicycles made with components A are more prone to wobble oscillations. In order to have a better comprehension of the different influence of fork and frame compliance, first the two forks (with the front wheel) are modally tested with the steer tube locked to a very stiff structure, then, the whole bicycles are tested. Modal analysis is carried out with the impulse method, for the analysis of each bicycle 60 FRFs are measured. The results of modal analysis are presented and the influence of identified modes on bicycle stability is discussed. An important issue of modal analysis of vehicles is the correlation between modal tests carried out in the laboratory and bicycle behavior on the road. When the vehicle is tested in the laboratory, additional constraints are added to guarantee equilibrium, but centrifugal forces are not present, because the vehicle is stationary. Since the analysis of the equations of linearized dynamics shows that the stiffness matrix includes a part due to centrifugal effects, the additional stiffness terms due to constraints in laboratory tests can be assumed to be equivalent to the centrifugal terms of the stiffness matrix at a certain speed. Details and limits of this equivalence are presented and discussed in the paper.
Application of Meshless Integral Method in Soil Mechanics
Authors: Ma Jeff , Summers Joshua David , Joseph Paul F.
Published: June 2012

An elastic-perfect plastic model associated with the Mohr-Coulomb yield criterion is applied to describe the behavior of soil material in the framework of Meshless Integral Method (MIM) [1][2]. In MIM, we obtained the governing integral equation from the weak form of elastoplasticity over a local sub-domain and the meshless function approximation is realized by using moving least-squares approximation. The advantages of this method are efficient removing of singularity by subtraction method, more accurate handling of the weak singularity, and the exact imposition of essential boundary conditions. Two flow rules of Mohr-Coulomb yield criterion are considered: associative and non-associative. Solution algorithm for elastoplastic analysis is given in detail. The results obtained through these two flow rules are compared and the meshless results are also compared to the FEM results. The numerical results show the accuracy and robustness of the meshless integral method in soil mechanics.
Study of Air Bubble Formation for Wastewater Treatment
Authors: Miletta Bryan A. , Amano R. S. , Alkhalidi Ammar A. T. , Li Jin
Published: June 2012

Aeration, a unit process in which air and water are brought into intimate contact, is an extremely important step in the process of wastewater treatment. The two most common systems of aeration are subsurface and mechanical. A mechanical system agitates the wastewater by various means (e.g. paddles, blades, or propellers) to introduce air from the atmosphere. Subsurface aeration is the release of air, in the form of bubbles, within the tank of wastewater to supply the microorganisms with the required amount of oxygen they need to metabolize and break down the organic material suspended in the wastewater. The bubbles of Air are released from the bottom of the wastewater tank through diffusers. These diffusers have a surface membrane, usually made of punched rubber, to create the fine bubbles with high oxygen transfer efficiency from supplied air to the diffusers. Since the energy crisis in the early 1970’s, there has been increased interest in these systems due to its high oxygen transfer efficiency. This paper covers experimentation of different air diffuser membranes, varying in material, used in the aeration process of wastewater treatment. Rubber, EPDM rubber (ethylene-propylene-diene Monomer) and PTFE Polytetrafluoroethylene membranes coated membranes were tested. Experimental results showed that the rubber membrane produced the smallest bubble size against expectation. This could be a result of the coating being on the top surface only and the bubble starts from inside the punch.
An Improved Design of Hammer Drill Efficiency
Authors: Konkel Michael , Fargen Ryan , Amano R. S. , Kumar Sourabh
Published: June 2012

The following report illustrates the design steps to complete the hammer drill efficiency project. The main goal of the project is to provide a mathematical relationship between the variables that make up the hammer drill. Once established these relations will allow the designer to predict the rate at which holes may be drilled. This will be accomplished by completing a Design of Experiments (DOE) study. A DOE is a systematic way to carry out experiments to gather data about how varying each variable of the tool will affect the performance of the tool. The variables that will be studied are drill time, beats per minute, force on the tool, revolutions per minute, and cam geometry. After successful completion of the various experiments the designer will be able to predict how the tool will perform under various parameters.
Stability and Convergence of Implicit Numerical Methods for a Class of Fractional Advection-Dispersion Models
Authors: Liu Fawang , Zhuang Pinghui , Burrage Kevin
Published: June 2012

In this paper, a class of fractional advection-dispersion models (FADM) is investigated. These models include five fractional advection-dispersion models: the immobile, mobile/immobile time FADM with a temporal fractional derivative 0 < γ < 1, the space FADM with skewness, both the time and space FADM and the time fractional advection-diffusion-wave model with damping with index 1 < γ < 2. They describe nonlocal dependence on either time or space, or both, to explain the development of anomalous dispersion. These equations can be used to simulate regional-scale anomalous dispersion with heavy tails, for example, the solute transport in watershed catchments and rivers. We propose computationally effective implicit numerical methods for these FADM. The stability and convergence of the implicit numerical methods are analyzed and compared systematically. Finally, some results are given to demonstrate the effectiveness of our theoretical analysis.
Design Attributes for Geometry Optimization Process of Thin Walled Honeycomb Structures
Authors: Sadeghi-Esfahlani Shabnam , Shirvani Hassan , Nwaubani Sunday , Shirvani Ayoub
Published: June 2012

Thin walled cellular structures have the ability to absorb impact energy during crashing thus it is important to enhance the crashing efficiency and optimise the structural reliability. This paper discusses the honeycomb cell configuration optimization procedure. For the design optimization, the response surface method (RSM) is used to formulate the complex design where the energy absorption (EA) representing the structure’s ability of absorbing energy was selected as objective, the Y split side parting length w1, w2, and thickness T1 are defined as three design variables, and the maximum crushing force (Max.F) occurs as constraint. During this distinctive optimization, the (RSM) was combined with detailed geometrically simplified finite element (FE) model using ANSYS/LS-DYNA (pre-processor), LS-DYNA (solver) and LS-Opt (optimiser). RSM combined with (FE)model without user intervention, was the effective tool to optimize non-linear impacted cellular structures. Optimal design achieved through LS-OPT is compared to the validated results for accuracy and effectiveness.
A Methodology to Detect the Precise Instant of Contact in Multibody Dynamics
Authors: Flores Paulo
Published: June 2012

The main purpose of this work is to present a general and comprehensive approach to automatically adjust the time step for the contact and non contact periods in multibody dynamics. The basic idea of the described methodology is to ensure that the first impact within a multibody system does not occur with a large value for relative bodies’ penetration in order to avoid the artificially large contact forces associated. The detection of the instant of contact takes place when the distance between two bodies change the sign between two discrete moments in time. In fact, in theory, the contact starts when this distance is zero, or a very small value to prevent the round-off errors. Thus, during the numerical solution of the system equations of motion if the first penetration is below this small value previously specified, then the current time is taken as the impact time. On the other hand, if the first penetration is larger than the specified tolerance, then the current time step is beyond the impact time. In this case, integration algorithm is forced to go back and take a smaller time step until a step can be taken within the acceptable tolerance. The main features of this approach are the easiness to implement and the good computational efficiency. In addition, it can easily deal with the transitions between non contact and contact cases in multibody dynamics. Finally, results obtained from dynamic simulations are presented and discussed to study the validity of the methodology proposed in this work.
Numerical Analysis of Sub-Atomic AFM Imaging in Ultra-High Vacuum: Coupling Quantum Mechanics With Continuum Dynamics
Authors: Wright C. Alan , Solares Santiago D.
Published: June 2012

Recent reports of sub-atomic resolution AFM images acquired using transition metal tips have sparked debate within the AFM community. However, an in-depth theoretical feasibility study of this work has yet to be produced. We focus on the tungsten/graphite system investigated by Hembacher and coworkers [Science 305, 380–383 (2004)] in which experimental higher-harmonics images revealed four-leaf clover symmetry features within the tungsten atom diameter. The authors interpret these features as the footprint of four bonding lobes of increased charge density at the tip apex atom, thought to be caused by covalent-like bonding in the bulk. Here we present our development of a computational method ranging from density functional theory to continuum dynamics for simulating the imaging process. We find that four lobes of increased electronic density are indeed present for W(001) tips and demonstrate the ability of the chemical forces on the tip apex atom to produce higher harmonics images.
Influence of Tooth Modifications on Load Distribution in Face-Hobbed Spiral Bevel Gears
Authors: Simon Vilmos V.
Published: June 2012

In this study a novel method for load distribution calculation is applied to investigate the influence of tooth modifications on loaded tooth contact in face-hobbed spiral bevel gears. As a result of these modifications introduced to the teeth of the pinion, the gear pair becomes mismatched, and a point contact replaces the theoretical line contact. In the applied load distribution calculation it is assumed that the point contact under load is spreading over a surface along the whole or part of the “potential” contact line, which line is made up of the points of the mating tooth surfaces in which the separations of these surfaces are minimal. The separations of contacting tooth surfaces are calculated by applying the full theory of tooth surface generation in face-hobbed spiral bevel gears. A computer program was developed to implement the formulation provided above. By using this program the influence of tooth modifications introduced by the variation in machine tool settings and in head cutter profile on load and pressure distributions, transmission errors, and fillet stresses is investigated and discussed.
Quadrotor UAV Control: Online Learning Approach
Authors: Pipatpaibul Pong-in , Ouyang P. R.
Published: June 2012

Quadrotor unmanned aerial vehicles (UAVs) are recognized to be capable of various tasks including search and rescue and surveillance for their agilities and small sizes. This paper proposes a simple and robust quadrotor controller utilizing online Iterative Learning Control (ILC) that is known to be useful for tasks performed repeatedly. The controller is used for trajectory tracking to perform a variety of manoeuvring such as take-off, landing, smooth translation, and circular trajectory motion. Different online ILCs are studied and simulation results prove the ability to gain full autonomy and perform successfully certain missions in the presence of considerably large disturbances.
Topology Optimization of Energy Harvesting Skin Structure Utilizing Harmonic Vibration
Authors: Lee Soobum , Tovar Andres
Published: June 2012

This paper presents a piezoelectric energy harvesting skin (EHS) design using topology optimization. EHS was motivated to embody a power-generating skin structure by attaching thin piezoelectric patches onto a vibrating skin for the purpose of self-sustainable health monitoring with wireless sensors. In this paper the hybrid cellular automata (HCA) algorithm is involved to optimize piezoelectric material distribution on a harmonically vibrating skin structure. Valid computational (finite element) models for vibrating structure are constructed, and the optimal piezoelectric material distribution is found on a surface of the structure. The piezoelectric material is modeled with penalization, and the optimal density and poling direction is found per each piezoelectric finite element using HCA algorithm. HCA algorithm demonstrated its ability to find the optimal design for piezoelectric material to yield maximum power output.
Accuracy Evaluation of PRBM for Predicting Kinetostatic Behavior of Flexible Segments in Compliant Mechanisms
Authors: Chen Guimin , Zhang Aimei
Published: June 2012

The pseudo-rigid-body model (PRBM) method has been widely accepted as one of the most important tools for synthesis and analysis of compliant mechanisms. However, the lack of quantitative study on the accuracy of PRBM for predicting the kinetostatic behavior of flexible members always makes users feel unconfident in the results achieved by PRBM. In this paper, a strain-energy-based approach is proposed for evaluating the accuracy of PRBM for predicting kinetostatic behavior of flexible segments, which compares the results of strain energy calculate using PRBM to those obtained using the derived closed-form solutions. The approach was used to evaluate the accuracy of the PRBM for flexible cantilever beams. It is proved that the PRBM is accurate for modeling segments subject to end-moment loads. A thorough comparison for segments subject to end-force loads is also presented. The results could be useful for PRBM users to assess the accuracy of the models for their compliant mechanism designs, or to choose appropriate values for the characteristic parameters. The results may also be used to improve the PRBM.
Mechanism of Bistable Resonance With Large Frequency
Authors: Leng Yong-gang , Lai Zhi-hui , Xia Jun-zhong , Guo Yan
Published: June 2012

For the response of a bistable system to a large frequency signal, the mechanism of large frequency resonance with parameter-adjusted bistable system is investigated in this work. Our research shows that the method of re-scaling frequency used in stochastic resonance does not change the bistable system structure to realize resonance at the small frequency corresponding to the large frequency, and that the method of tuning bistable system parameters can directly produce resonance at the large frequency through adjusting the system parameters to change the system structure.
A Highly Sensitive Electrochemical Impedimetric Nanobiosensor for Dust Mite Antigen Der p2 Detection
Authors: Bau I-Jiuan , Wang Gou-Jen
Published: June 2012

The group 2 allergen, Der p2, has been reported to activate innate toll-like receptors (TLRs) on respiratory epithelial cells and thus aggravate respiratory diseases. In this study, a high sensitive nanobiosensor based on a 3D sensing element that has uniformly deposited gold nanoparticles for the detection of the dust mite antigen Der p2 is proposed. The barrier layer of an anodic aluminum oxide (AAO) film is used as the template in this highly sensitive nanobiosensor fabricated with a reducing agent and stabilizer-free method. Electrochemical deposition is utilized to synthesize uniformly distributed gold nanoparticles on the surface of the barrier layer. The size and the distribution density of the nanoparticles can be well controlled by the potential applied during electrochemical deposition. Following this procedure, monoclonal antibodies were immobilized against the dust mite antigen Der p2 by the gold nanoparticles through the 11-MUA (11-mercaptoundecanoic acid), EDC (1-Ethyl-3-(3-dimethyl-aminopropyl)-carbodiimide)/NHS (N-hydroxysuccinimide) self-assembled monolayer approach. The proposed nanobiosensor was successfully used to examine the Der p2 down to a concentration of 1pg/mL through the electrochemical impedance spectroscopy analysis. The high sensitivity of the proposed 3D nanobiosensor can be attributed to the high intensity and uniformity of the Au nanoparticles on the sensor. The proposed nanobiosensor would be useful for the fast detection of rare molecules in a solution.
Hardware Support for Efficient Testing of Embedded Software
Authors: Reinbacher Thomas , Steininger Andreas , Mu¨ller Tobias , Horauer Martin , Brauer Jo¨rg , Kowalewski Stefan
Published: June 2012

Verification of software for embedded systems is crucial for ensuring a product’s integrity. Formal approaches like static analysis and model checking are gaining momentum in this context. To make an exhaustive examination of the system’s state space tractable in practice, these methods perform an abstraction and over-approximation of the possible behavior. As a side-effect, however, this leads to “false negatives” -property violations that exist only in the model and not on the real system. Ruling out such spurious property violations by manual valuation is a tedious and error-prone process. This paper reports on the concepts and design of a hardware unit to support the identification of false negatives. Our approach has several advantages: (i) It works on microcontroller binary code, thus avoiding the need for availability of high-level source code, and covering compiler bugs as well, (ii) Moving the verification directly to the target platform rules out modeling errors. (iii) The cases suspected to lead to spurious property violations can serve as very efficient test cases for a specific implementation later on. We illustrate principle and benefits of the proposed approach by a worked example.
Multi-Degree-of-Freedom Modeling of Mechanical Snubbing Systems
Authors: Kaul Sudhir
Published: June 2012

This paper presents a multi-degree-of-freedom model for the analysis of mechanical snubbing in elastomeric isolators. The model uses a system of elastomeric isolators and snubbers to assemble a rigid body with three degrees-of-freedom to a rigid frame. The isolators are supplemented by the snubbing system so as to limit the displacement of the rigid body in all three directions of motion when the system undergoes transient loading or overloading conditions. The model is piecewise non-linear and uses normalized Bouc-Wen elements in order to capture inherent hysteresis of the elastomeric isolators and the snubbing system as well as the transition in stiffness and damping properties resulting due to inherent coupling between the isolators and the snubbing system. Separate elements are used to model the enhanced stiffness resulting from the snubbing system in the translational directions of motion. A set of elastomeric isolators and snubbing systems is used for data collection, characterization and model validation. The data collection is carried out at multiple strain amplitudes and strain rates. A conventional least squares based parameter identification technique is used for characterization. The completely characterized model is then used for simulating the response of the rigid body and the simulation results are compared to experimental data. The simulation results are found to be in general agreement with the experimental data.
Tuning Methodology of Nonlinear Vibration Absorbers Coupled to Nonlinear Mechanical Systems
Authors: Viguie´ Re´gis , Kerschen Gae¨tan
Published: June 2012

A large body of literature exists regarding linear and nonlinear dynamic absorbers, but the vast majority of it deals with linear primary structures. However, nonlinearity is a frequent occurrence in engineering applications. Therefore, the present paper focuses on the mitigation of vibrations of nonlinear primary systems using nonlinear dynamic absorbers. Because most existing contributions about their design rely on extensive parametric studies, which are computationally demanding, or on analytic methods, which may be limited to small-amplitude motions, this study proposes a tuning procedure which is computationally tractable and can treat strongly nonlinear regimes of motion. The proposed methodology relies on a frequency-energy based approach followed by bifurcation analysis. The results are illustrated using a one-degree-of-freedom primary system, which can, for instance, represent the vibrations of a specific mode of a multi-degree-of-freedom structure.
Modeling and Using Product Architectures in Industrial Mechatronic Product Development: Experiments and Observations
Authors: Alvarez Cabrera Andre´s A. , Foeken Maarten J. , Woestenenk Krijn , Stoot Guy , Tomiyama Tetsuo
Published: June 2012

The goal of this work is to practically determine the role of product architecture models to support communication for improving development practices of complex mechatronic products. This paper contains descriptions, observations, and lessons learned from case studies in which the authors tested a language to represent product architectures during product development in a company, as well as the reasons leading to the use of the specific language/model. The tests include construction of architecture models, direct use of the architecture information, model generation from the architecture model, reuse of architecture model information, clarification of existing documentation, and transition towards model-based product development. The work points out desired characteristics of product architecture models as well as characteristics of the necessary implementation tools and framework.
A Coding Scheme for Analyzing Capstone Design Reports: Problem and Solution Descriptions
Authors: Joshi Shraddha , Summers Joshua D.
Published: June 2012

It is desirable that the graduating engineering students possess the skills of formulating and solving engineering problems to design solutions that meet the established requirements. However, the current literature has noticeable gaps pertaining to understanding how the formulation of design problems and establishment of requirements affect the final design solution. The ultimate goal of this research is to understand the influence of the level of detail of problem statement and requirements on the level of detail of final solution. In order to accomplish this goal a coding scheme is developed to systematically code the information in the final design reports from capstone design class collected over a period of ten years from 1999 to 2008. The coded information is used to develop mappings between problem statement and final solution. To this end, this paper describes the scheme for systematically coding the problem statement and final design solution.