bluuebunny/crossref_metadata_2025 huggingface dataset:
Acute Drug Administration in Epilepsy: A Review
Authors: Wolf Peter
Published: July 2010

Aims: To review acute administration of drugs in epilepsy for indications other than status epilepticus. Discussion: This review looks into the application of acute drug administration (ADA) against febrile and prolonged nonfebrile seizures in children, seizure clustering (habitual or at drug withdrawal), catamenial epilepsy, response to seizure “warnings”, and prophylaxis of seizures at perceived increased risk (reflex epilepsies, long‐distance travel, lifestyle, and social occasions). The drugs most commonly used for ADA are the benzodiazepines diazepam (oral or rectal), clobazam and buccal or nasal midazolam, and lorazepam. Others include valproic acid, nitrazepam, acetazolamide, chloral hydrate, pyridoxine, and antipyretics. Conclusions: The best evidence for the efficacy of ADA exists in febrile and nonfebrile childhood seizures, whereas the evidence in catamenial epilepsy is weak. Prevention of clusters is a well‐proven principle but its application has been little studied. Prevention of imminent seizures predicted by well‐established triggers, defined risk factors, or premonitory minor seizure activity seems to be at the same time the most intelligent and the least investigated application of ADA and would deserve to be better studied.
The Use of Antidepressants for Headache Prophylaxis
Authors: Smitherman Todd A. , Walters A. Brooke , Maizels Morris , Penzien Donald B.
Published: July 2010

The focus of this review is on the efficacy of antidepressants as preventive treatments for migraine and chronic tension‐type headache (TTH). Pharmacologic prophylaxis may be indicated for patients with frequent headaches, who respond insufficiently to acute therapies, or for whom medication overuse is a concern. The well‐documented efficacy of the tricyclic antidepressant amitriptyline, both for migraine and chronic TTH, has been followed by widespread use of other antidepressants for headache prophylaxis. Although antidepressants in general share comparable efficacy for the treatment of depressive disorders, their efficacy as headache preventives varies widely. Evidence supporting use of the selective serotonin reuptake inhibitors as headache preventives is poor; their use should be reserved for treating comorbid depression in a patient who also has a headache disorder. Small randomized trials of venlafaxine indicate preliminary efficacy both for migraine and tension‐type headache. Evidence for other antidepressants is lacking. Although antidepressants are often prescribed to headache patients under the assumption that the prescribed agent also will be effective in reducing symptoms of comorbid depression, the majority of studies have failed to find a strong relationship between depression symptoms and headache improvement. Suggestions for future research are discussed.
Neuropsychiatric Adverse Effects of Centrally Acting Antiobesity Drugs
Authors: Nathan Pradeep J. , O’Neill Barry V. , Napolitano Antonella , Bullmore Edward T.
Published: July 2010

Introduction:Central neurochemical systems including the monoamine, opioid, and cannabinoid systems have been promising targets for antiobesity drugs that modify behavioral components of obesity. In addition to modulating eating behavior, centrally acting antiobesity drugs are also likely to alter emotional behavior and cognitive function due to the high expression of receptors for the neurochemical systems targeted by these drugs within the fronto‐striatal and limbic circuitry.Methods:This paper reviewed the neuropsychiatric adverse effects of past and current antiobesity drugs, with a central mechanism of action, linking the adverse effects to their underlying neural substrates and neurochemistry.Results:Antiobesity drugs were found to have varying neuropsychiatric adverse event profiles. Insomnia was the most common adverse effect with drugs targeting monoamine systems (sibutramine, bupropion and tesofensine). These drugs had some positive effects on mood and anxiety and may have added therapeutic benefits in obese patients with comorbid depression and anxiety symptoms. Sedation and tiredness were the most common adverse effects reported with drugs targeting the m‐opioid receptors (i.e., naltrexone) and combination therapies targeting the opioid and monoamine systems (i.e., Contrave™). Cognitive impairments were most frequently associated with the antiepileptic drugs, topiramate and zonisamide, consistent with their sedative properties. Drugs targeting the cannabinoid system (rimonabant and taranabant) were consistently associated with symptoms of anxiety and depression, including reports of suicidal ideation. Similar adverse events have also been noted for the D1/D5antagonist ecopipam.Conclusion:These findings highlight the need to assess neuropsychiatric adverse events comprehensively using sensitive and validated methods early in the clinical development of candidate antiobesity drugs with a central mechanism of action.
A new hybrid horsetail Equisetum×lofotense (E. arvense×E. sylvaticum, Equisetaceae) from Norway
Authors: Lubienski Marcus
Published: July 2010

On the Island of Austvågøya (Lofoten, Norway), a new hybrid horsetail (E. arvense×E. sylvaticum) was found, which is described as E.×lofotense. Its macro‐ and micro‐morphological characters are discussed and compared with the similar hybrid E.×mildeanum (E. pratense×E. sylvaticum) with which it shares the E. sylvaticum parentage. The hybrid nature is verified by its completely aborted spores, and the micro‐morphology of the stem ridges and stomata, illustrated by SEM images, confirm the proposed origin. An overview of all known hybrids in the genus Equisetum is given and critically commented. It becomes evident that in subgenus Equisetum E. arvense is the species most frequently involved in hybridization events.
Revised STandards for Reporting Interventions in Clinical Trials of Acupuncture (STRICTA): Extending the CONSORT Statement
Authors: MacPherson Hugh , Altman Douglas G. , Hammerschlag Richard , Youping Li , Taixiang Wu , White Adrian , Moher David ,   on behalf of the STRICTA Revision Group
Published: July 2010

The STandards for Reporting Interventions in Clinical Trials of Acupuncture (STRICTA) were published in five journals in 2001 and 2002. These guidelines, in the form of a checklist and explanations for use by authors and journal editors, were designed to improve reporting of acupuncture trials, particularly the interventions, thereby facilitating their interpretation and replication. Subsequent reviews of the application and impact of STRICTA have highlighted the value of STRICTA as well as scope for improvements and revision. To manage the revision process a collaboration between the STRICTA Group, the CONSORT Group, and the Chinese Cochrane Centre was developed in 2008. An expert panel with 47 participants was convened that provided electronic feedback on a revised draft of the checklist. At a subsequent face‐to‐face meeting in Freiburg, a group of 21 participants further revised the STRICTA checklist and planned dissemination. The new STRICTA checklist, which is an official extension of CONSORT, includes six items and 17 sub‐items. These set out reporting guidelines for the acupuncture rationale, the details of needling, the treatment regimen, other components of treatment, the practitioner background, and the control or comparator interventions. In addition, and as part of this revision process, the explanations for each item have been elaborated, and examples of good reporting for each item are provided. In addition, the word “controlled” in STRICTA is replaced by “clinical,” to indicate that STRICTA is applicable to a broad range of clinical evaluation designs, including uncontrolled outcome studies and case reports. It is intended that the revised STRICTA, in conjunction with both the main CONSORT Statement and extension for nonpharmacologic treatment, will raise the quality of reporting of clinical trials of acupuncture.
Theoretical approach to the hit probability of lung‐cancer‐sensitive epithelial cells by mineral fibers with various aspect ratios
Authors: Sturm Robert
Published: July 2010

Background:  Inhalation of fibers may lead to the damage and, as a further consequence, to the malignant transformation of specific (most of all non‐ciliated) cells of the bronchial and bronchiolar airway epithelium. In order to accurately estimate the cancer risk induced by inhaled fibers, hit probabilities of non‐ciliated (secretory) cells by mineral fibers (asbestos and chrysotile) were computed.

Methods:  Besides the use of a stochastic lung geometry and a particle transport/deposition model being based upon the random‐walk algorithm, histological data of cell distributions in the human lungs were applied for the theoretical calculations. Diameters of computer‐generated fibers ranged from 0.1 µm to 10 µm, whilst two values (3 and 100) were selected for the aspect ratios (ratios of fiber length to fiber diameter), thereby simulating the behavior of short and very long fibrous particles.

Results:  According to the modeling results, the highest regional hit probabilities (up to 10%) are available for fibers with a diameter of 1.0 µm, whereby cells of the bronchiolar compartment represent a preferential target of these particles. For fibers with a diameter of 0.1 µm, bronchiolar hit probabilities reach 2–3%, whereas fibers with a diameter of 10 µm penetrate to the peripheral lung parts with only low amounts (<0.1%). A change of the inhalation conditions from sitting to light‐work breathing enhances the extrathoracic and bronchial filtering of large particles (diameter ≥1 µm), whilst penetration of small particles towards distal lung airways is subject to a reinforcement. Further refinement of hit probabilities by considering single airway generations results in the circumstance that fibers with diameters ≤1.0 µm preferably collide with cancer‐sensitive cells of airway generations 12–15. In contrast, fibers with a diameter of 10 µm mainly represent a hazard for cancer‐sensitive cells being located in the uppermost airways. A change of breathing conditions both supports the effect of short fibers and enhances the filtering of long ones.

Conclusion:  Based upon the results of this contribution it can be concluded that highest cancer risk is generated by the inhalation of mineral fibers with diameters ≤1.0 µm, whereby fiber length has to be classified as a parameter with lower importance.
Relationship between urinary sodium excretion and pioglitazone‐induced edema
Authors: Nakamura Akinobu , Osonoi Takeshi , Terauchi Yasuo
Published: July 2010

To investigate the factors contributing to pioglitazone‐induced edema, we analyzed sodium excretion and several clinical parameters before and after administration of pioglitazone. We analyzed these parameters before and after 8 weeks of administration of pioglitazone to female subjects with type 2 diabetes. When we evaluated whether a significant correlation was found between salt excretion and blood pressure, six patients showed such correlation and 20 patients did not. After 8 weeks of pioglitazone administration, five patients had developed edema, and, surprisingly, such correlation was not found in all five subjects. Salt excretion after administration of pioglitazone was significantly lower in subjects who developed edema and those who showed the correlation, and the hematocrit was significantly lower after administration in the subjects who showed the correlation, but not in the edema group. Pioglitazone‐induced edema would be caused not only by fluid retention, but also by other factors, such as vascular permeability. (J Diabetes Invest, doi: 10.1111/ j.2040‐1124.2010.00046.x, 2010)
Effects of blood pressure and the renin‐angiotensin system on platelet activation in type 2 diabetes
Authors: Uzu Takashi , Sakaguchi Masayoshi , Tsuda Atsuko , Kadota Aya , Yokomaku Yukiyo , Kume Shinji , Kanasaki Masami , Isshiki Keiji , Araki Shin‐ichi , Sugiomoto Toshiro , Maegawa Hiroshi , Kashiwagi Atsunori
Published: July 2010

Aims/Introduction: Platelet‐derived microparticles (PDMP) are released from the platelets either after activation or in response to physical stimulationin vivo. The present study examined the association between blood pressure and PDMP, and the effects of high‐dose angiotensin receptor blockers (ARB) on PDMP in patients with type 2 diabetes.

Materials and Methods: The study subjects consisted of 28 type 2 diabetes patients with blood pressure ≥130/80 mmHg who were treated with valsartan (80 mg daily). The patients were randomly assigned to take either 80 mg of telmisartan (Tel group) or 160 mg of valsartan (Val group) and then were followed up for 24 weeks. Thereafter, the patients were switched to combination therapy (5 mg of amlodipine with 40 mg of telmisartan [Tel group] or 80 mg of valsartan [Val group]) for 12 weeks.

Results: Although the ambulatory blood pressure did not change, the PDMP levels were significantly decreased from baseline to week 24 (high dose ARB). In contrast, combination therapy reduced both blood pressure and PDMP levels compared with the baseline. Although the PDMP level was significantly correlated with the morning BP elevation at baseline and week 36 (combination therapy), this same relationship was not found at week 24. There were no significant differences in the blood pressure and PDMP levels between the two groups.

Conclusions: Patients with morning hypertension might be at risk for cardiovascular diseases. High‐dose renin‐angiotensin system inhibition and blood pressure control are both considered to reduce cardiovascular events in patients with type 2 diabetes.(J Diabetes Invest, doi: 10.1111/j.2040‐1124.2010.00048.x, 2010)
Factors Affecting Transmission Error in Helical Synchronous Belt With Error on Belt Side Face Under Bidirectional Operation
Authors: Kagotani Masanori , Ueda Hiroyuki
Published: July 2010

Helical synchronous belt drives are effective for reducing the noise and transmission error per single pitch of a pulley, as compared with conventional synchronous belt drives. However, the helix angle of the tooth trace causes axial belt movement. When the belt comes into contact with the pulley flange or moves away from the pulley flange due to bidirectional operation, the accuracy of finishing on the belt side face affects the transmission error. In addition, various factors, such as the transmitted torque, installation tension, pitch difference between the belt and the pulley, and alignment error between the driving and driven pulleys in the axial direction, are considered to affect the behavior of the transmission error. In the present study, the influence of various factors on the transmission error in a helical synchronous belt with the error on the belt side face was investigated. Specifically, the case in which a flanged pulley is rotated in bidirectional operation under the quasi-static condition and transmitted torque was examined. The transmission error in bidirectional operation considering the error on the belt side face increased with an increase in the transmitted torque, but was reduced when the installation tension was set to be high and when the pitch difference on the driving side was smaller than that on the driven side. In addition, the accuracy of rotation transmission improved when the alignment between the pulleys in the axial direction was set so that the belt on the driving side came into contact with the pulley flange earlier than the belt on the driven side.
Adaptive Designs of Experiments for Accurate Approximation of a Target Region
Authors: Picheny Victor , Ginsbourger David , Roustant Olivier , Haftka Raphael T. , Kim Nam-Ho
Published: July 2010

This paper addresses the issue of designing experiments for a metamodel that needs to be accurate for a certain level of the response value. Such a situation is common in constrained optimization and reliability analysis. Here, we propose an adaptive strategy to build designs of experiments that is based on an explicit trade-off between reduction in global uncertainty and exploration of regions of interest. A modified version of the classical integrated mean square error criterion is used that weights the prediction variance with the expected proximity to the target level of response. The method is illustrated by two simple examples. It is shown that a substantial reduction in error can be achieved in the target regions with reasonable loss of global accuracy. The method is finally applied to a reliability analysis problem; it is found that the adaptive designs significantly outperform classical space-filling designs.
Design Method of Double Ball Artifact for Use in Evaluating the Accuracy of a Gear-Measuring Instrument
Authors: Komori Masaharu , Takeoka Fumi , Kondo Koshi , Kondo Yohan , Takatsuji Toshiyuki , Osawa Sonko , Kubo Aizoh
Published: July 2010

Vibration of gears is a serious problem in mechanical devices. The characteristics of these vibrations are strongly affected by tooth flank form deviation of micrometer or submicrometer order. The quality of manufactured gears is controlled by a gear-measuring instrument. The accuracy of the profile measurement by such an instrument is evaluated using a master gear or an involute artifact. However, it is difficult to manufacture gears with high accuracy because the involute is a complicated geometrical form. To solve this problem, the double ball artifact (DBA) has been proposed as a means to evaluate the profile measurement accuracy. The application of the DBA requires a DBA design method so that the DBA can be applied to a wide variety of gear dimensions in the industrial field and can realize high-precision evaluation. In the present study, a design method is proposed for the DBA, and the dimensions, tolerance, and material of the DBA are determined. A DBA is designed and manufactured according to the proposed design method and the effectiveness of the manufactured DBA is verified experimentally using a gear-measuring instrument.
Design and Testing of a Thin-Flexure Bistable Mechanism Suitable for Stamping From Metal Sheets
Authors: Todd Benjamin , Jensen Brian D. , Schultz Stephen M. , Hawkins Aaron R.
Published: July 2010

We present a new technique for fabricating compliant mechanisms from stamped metal sheets. The concept works by providing thinned segments to allow rotation of flexural beams 90 deg about their long axis, effectively providing a flexure as wide as the sheet’s thickness. The method is demonstrated with the design and fabrication of a metal bistable mechanism for use as a threshold accelerometer. A new model based on elliptic integral solutions is presented for bistable mechanisms incorporating long, thin flexures. The resulting metal bistable mechanisms are tested for acceleration threshold sensing using a drop test and a vibration test. The mechanisms demonstrate very little variation due to stress relaxation or temperature effects. The force-displacement behavior of a mechanism is also measured. The mechanisms’ switching force is less than the designed value because of out-of-plane motion and dynamic effects.
Preliminary Study of Fire Spread in Cities and Forests, Using PMMA Specimen as a Fuel in CFD Simulations
Authors: Satoh Koyu , Liu Naian , Liu Qiong , Yang K. T.
Published: July 2010

It is important to examine the behavior of forest fires and city fires to mitigate the property damages and victims by fires. There have been many previous studies on forest fires where the fire spreading patterns were investigated, utilizing artificial satellite pictures of forest fires, together with the use of corresponding weather data and GIS data. On the other hand, large area city fires are very scarce in the world, particularly in modern cities where high-rise concrete buildings are constructed with sufficient open spaces. Thus, the examples of city fires to be referred are few and detailed investigations of city fires are limited. However, there have still been existing old cities where traditional houses built with flammable material such as wood, maybe historically important, only separated with very small open spacing. Fires may freely spread in those cities, once a big earthquake happens there and then water supply for the fire brigade is damaged in the worst case along with the effect of strong wind. There are some fundamental differences between the forest fires and city fires, as the fuel may distribute either continuously or discretely. For instance, in forest fires, the dead fallen leaves, dry grasses and trees are distributed continuously on the ground, while the wooden houses in cities are discretely distributed with some separation of open spacing, such as roads and gardens. Therefore, the wooden houses neighboring the burning houses with some separation are heated by radiation and flames to elevate the temperatures, thus causing the ignition, and finally reaching a large city fire. The authors have studied the forest fire spread and are planning to start a laboratory experiment of city fire spreading. In the preliminary investigation, a numerical study is made to correlate with the laboratory experiment of city fire propagation, utilizing the three-dimensional CFD simulations. Based on the detailed experimental analysis, the authors are attempting to modify the three dimensional CFD code to predict the forest fires and city fires more precisely, taking into account the thermal heating and ignition processes. In this study, some fundamental information on the city fire propagation has been obtained, particularly to know the safe open spacing distances between the houses in the cities and also the wind speed.
A Methodology for Predicting the Durability of Adhesively Bonded Joints in Cathodic Environments
Authors: Hamade R. F.
Published: July 2010

This paper represents a concise summary of several published studies by the author and coworkers (1–7) on the topic of debonding of adhesively bonded (elastomer-to-steel) joints under cathodic conditions. Together, these studies amount to a verified methodology for quantitatively predicting the debonding of adhesive bonded joints in cathodic environments. Based on extensive experimental debond data collected by the author and coworkers, mathematical models are developed that are capable of predicting the life of adhesive bonds under cathodic conditions (some being highly accelerated) of varying voltage, temperature, and applied stress.
New Technique Measuring Film Thickness for Tribological Machines
Authors: Al-Haddad A. A. , Salih Nbhan D. , Chin Chee Wen , Yusaf T. F. , Yousif B. F.
Published: July 2010

In the present work, a prototype machine was developed for film thickness measurement for tribological tests. The configuration of the machine was based Block on Ring (BOR) technique. In the current machine, frictional forces and film thickness were measured using load cell and strain gauges, respectively. Calibration was made to determine the real film thickness. Experiments were conducted using the newly developed machine to investigate the film thickness during sliding of UHMWPE against aluminum alloy counterface. The tests were performed at applied loads (1.47 N–2.94 N). The results revealed that increases the applied load reduces the film thickness which in turn played a main role in controlling the surface characteristics of the polymer.
Kenaf Fibers for Tribo-Thermoplastic Composites
Authors: Singh Narish , Rilling Dirk , Yousif B. F.
Published: July 2010

In the present work, wear and frictional characteristics of thermoplastic epoxy resin reinforced with treated kenaf fiber (T-KFRE) is investigated. The T-KFRE composite was tested against smooth stainless steel using a block on disc (BOD) apparatus at 2.8m/s sliding velocity and variable applied loads (10–60N) and sliding distance (02.7km). The T-KFRE was investigated under Parallel (PO) in relation to sliding direction. Adhesive wear results revealed that T-KFRE has a superior and high degree of wear resistance when slid against a stainless steel counter face in comparison to neat epoxy. The friction coefficient varied between the ranges of 0.35 and 0.65 in relative to sliding distance of up to 2.7 km. SEM study showed different wear mechanism such as pitting, delamination, breakage and micro cracks especially for lighter applied loads. Meanwhile, heavier loads showed less damage to the surface, which in turn exhibited, better wear performance and frictional characteristics.
An Investigation Into the Influence of Weld Induced Residual Stresses on the Structural Behaviour of Built-Up EN 1.4003 Columns
Authors: Klopper Johan J. , Laubscher Rudolph F.
Published: July 2010

The presence of longitudinal residual stresses within built-up sections may have a marked effect on their structural behaviour when used as a column [1]. EN 1.4003, also known as 3CR12, is a weldable utility stainless steel developed to provide a superior alternative to coated carbon steels and other alloys which have poor corrosion/abrasion resistance [2]. It is also an economical substitute for conventional stainless steel where environmental conditions do not justify higher alloy content. Hot-rolled structural sections are not readily available in stainless steel and are therefore usually build up by arc and lately laser welding. This paper presents the results of an investigation into the effects of thermally induced residual stresses on the structural behaviour of fabricated EN 1.4003 T-sections. Manual metal arc (MMA) welding and Laser welding are compared as regards to the induced residual stress distribution during fabrication. The residual stresses were measured using the neutron diffraction method. The effect of these measured residual stresses is investigated by incorporation into a non-linear finite element analysis. The buckling strength of a limited number of full scale columns was measured. Conclusions as regards to their effect on the structural integrity of the sections under investigation are made.
Form Follows Form: Is a New Paradigm Needed?
Authors: Bohm Matt R. , Stone Robert B. , Nagel Robert L.
Published: July 2010

This paper presents a new form-based concept generation technique known as Form Follows Form (FFF). The technique allows a novice engineer or designer to use natural language to specify components envisioned within a product to initiate a more thorough concept generation process. Form follows form takes the initial component solution and then formulates the underlying function structure by leveraging a repository of over 5500 artifacts. Existing computational conceptual design methods are then employed to automatically display a set of ranked concept alternatives to the user. Users can choose from two different levels of interaction, an automatic mode that uses the most common functions to develop concept alternatives, or a mode that allows the user to be more precise in defining a product’s interaction. The computational algorithms and grammar rules are detailed along with a case study using both tiers of interaction.
Nonlinear Behaviour of Equivalent Stiffness of Plates Clamped by Bolted Joints Under Loading
Authors: Naruse Tomohiro , Shibutani Yoji
Published: July 2010

The equivalent stiffness of clamped plates is needed not only to evaluate the strength of bolted joints but also to estimate the deformation and vibration characteristics of practical structures with many bolted joints. The axial stiffness and bending stiffness of clamped plates were estimated using finite element (FE) analyses while taking the contact conditions on bearing surfaces and between plates into account. We constructed FE models with an M10 bolt and plate thicknesses of 3.2, 4.5, 6.0, or 9.0 mm, and subjected them to an axial load and a bending moment. The axial compliance was estimated using the load-displacement relation obtained from the FE results. When the axial load was lower than 110% of the clamping force, the load-displacement relation showed linear behaviour and the axial compliance was almost constant. When the axial load was higher than that, the axial compliance varied nonlinearly with changes in the contact conditions between clamped plates. The compliances of the clamped plates were compared with those specified in the German engineering society code VDI 2230 (2003), in which equivalent conical compressive stress fields in the plates had been assumed. When the load-displacement relation behaves linearly, the axial and bending compliances obtained in FE analysis can basically be expressed by the VDI 2230 (2003) code. However, this code gives the slightly large axial stiffness, and thus the internal force borne to the bolt is predicted in a little bit unsafe estimation. In addition, the code is not suitable for application in the case of clamped plates with different thicknesses due to the assumptions it makes with respect to models.
An Efficient Numerical Model of Pulsating Combustion and Its Experimental Validation
Authors: Casarsa Luca , Giannattasio Pietro , Micheli Diego
Published: July 2010

A simple and efficient numerical model is presented for the simulation of pulse combustors. It is based on the numerical solution of the quasi-1D unsteady flow equations and on phenomenological sub-models of turbulence and combustion. The gas dynamics equations are solved by using the Flux Difference Splitting (FDS) technique, a finite-volume upwind numerical scheme, and ENO reconstructions to obtain second-order accurate non-oscillatory solutions. The numerical fluxes computed at the cell interfaces are used to transport also the reacting species, their formation energy and the turbulent kinetic energy. The combustion progress in each cell is evaluated explicitly at the end of each time step according to a second-order overall reaction kinetics. In this way, the computations of gas dynamic evolution and heat release are decoupled, which makes the model particularly simple and efficient. A comprehensive set of measurements has been performed on a small Helmholtz type pulse-jet in order to validate the model. Air and fuel consumptions, wall temperatures, pressure cycles in both combustion chamber and tail-pipe, and instantaneous thrust have been recorded in different operating conditions of the device. The comparison between numerical and experimental results turns out to be satisfactory in all the working conditions of the pulse-jet. In particular, accurate predictions are obtained of the device operating frequency and of shape, amplitude and phase of the pressure waves in both combustion chamber and tail-pipe.
Improved Discrete Ordinates Method for Ray Effects Mitigation
Authors: Huang Zhi-Feng , Zhou Huai-Chun , Hsu Pei-feng
Published: July 2010

A new and improved method based on the discrete ordinates scheme with infinitely small weights (DOS+ISW) is developed for radiative heat transfer in three-dimensional participating media. To demonstrate the effectiveness of the method, ray effects caused by 1) abrupt step changes in the boundary conditions and 2) the stepwise variation of the medium emissive power are discussed. In this work, angular quadrature sets with large number of discrete ordinate directions are chosen to mitigate ray effects, while at the same time keeping the computational time increase to a minimum. Comparing with the conventional discrete ordinates method, the difference is that intensities in these directions are calculated by DOS+ISW. Intensity with fine directional resolution calculated by this method is validated by comparing with that of Reverse Monte Carlo method. The large number of discrete ordinates directions used in the new method becomes computationally prohibitive in discrete ordinates method due to the increased computer memory and computation time requirements.
Computer-Aided Grid-Editing System for Supporting the Design of Rapid Prototyping Transtibial Sockets
Authors: Chuang Wei-Chiao , Hsu Lai-Hsing , Huang Gwo-Feng , Lai Chih-Wei
Published: July 2010

This study is to develop an easily-used editing system for designing a transtibial socket that will be fabricated by a rapid prototyping (RP) machine. This study uses STL format data to construct the editing model. This grid-editing system is developed by employing C++/CLI and the OpenGL graphic interface. It could conveniently import three-dimensional scanner data and export appropriate data format for RP machines. The proposed system includes filtering the point data, generating mesh, and editing point data. After being edited, a socket is constructed by the mesh model. The socket model is then coupled with a base that will be used to connect a shank. Because the system only modifies the point data, it could have high efficiency and freedom while designing transtibial sockets. To achieve an easy-to-use program, the self-developed software is very distinct with other commercial software, such as colliding deformation and grid-editing methods. Based on the concept of virtual reality, users could operate this software intuitively. This system may allow a prosthetist to design RP sockets conveniently. The results of case studies demonstrated the feasibility of this grid-editing system for transtibial socket design.
Detection of Defects in Welded Structures With Complex Geometry Using Statistical Method Based on Discrete Wavelet Transform
Authors: Wu Tsun-Yen , Ume I. Charles , Rogge Matthew D.
Published: July 2010

In this paper, an inspection system and a defect detection method are presented. A welded sample with complex geometry was placed on an inspection system and inspected by generating ultrasound on one side of the weld and receiving on the other with an electromagnetic acoustic transducer (EMAT) sensor. Ultrasonic signals along the weld were acquired at locations with 1 mm distance between inspections. In order to detect the presence of defects, a statistical method based on Discrete Wavelet Transform (DWT) is implemented. Energy of each location along the weld is calculated and useful information indicating presence of defects is extracted by DWT using different mother wavelets. By comparing the energy distribution obtained from a particular sample, or a target, with a baseline energy distribution, defect locations are predicted. The baseline energy distribution is obtained by averaging energy distributions calculated for all inspected samples. The difference between a target and the reference is viewed as an indication of presence of defects. The results showed that the method can isolate signal changes that were caused by defects. Comparison to destructive cut-checks shows the accuracy of defect detection is high.
Reconfigurable Clamping Device Based on Multi-Function Link and Hydraulic Cylinder With Built-In Piston Rod
Authors: Zhou Lufei , Zhong Kangmin , Sheng Xiaoming
Published: July 2010

Reconfigurable clamping devices based on multi-function linkage and rod-less piston cylinder by fluid transmission were introduced. Their working principles have been introduced, and the relevant mechanics calculation formulas were presented. In these devices, rod-less piston cylinder was used as a drive, while multi-function bars and wheels with simple and similar geometric shapes as the basic components. The needs for the clamping of workpieces with different sizes or shapes and requirements for the line-contact or face-contact clamping can be meet by changing the shapes of the basic components and the locations, meanwhile great clamping force can be provided. Due to the rapid reconstruction, the demands of multi-type, variable-volume and short periods can be satisfied.
Managing the Mechanical Data Base
Authors: Beiski Yuval
Published: July 2010

Developing complex systems usually involves many activities that are based on the integration of the designer CAD models: mechanical assemblies, analysis models (CFD, FEA, Thermal, etc.), interface control, tool and jig design data, production models, mass properties, ILS, documentation, and many more. Proper management of the integrated data base can lead to cost and time savings by parallel design, updated interfaces, and minimum integration faults; and can increase the reuse of parts and support the system engineering decisions. On the other hand, improper data managing can lead to major failures in the design process and during the mechanical assembly, which might result in loss of time, money and reputation. In order to assure efficient and accurate management of the mechanical data base, special training is required for designated personnel – the Mechanical Integrator (MI). The Mechanical Integrator ensures the implementation of appropriate working procedures by the sub-systems designers, that the current design is based on approved and released data, the use of generic parts and much more by managing an updated and robustly built data base. The Mechanical Integrator has a major roll in the project, but does he have the necessary knowledge and training? This paper presents the advantages of managing the mechanical data base; focusing on the techniques in use for building and monitoring it properly and explains the training program of the Mechanical Integrator, a person in charge over the mechanical data base and data flow.
Study of the Effects of Miniaturization on Static and Dynamic Form Errors in Desktop Milling Machines
Authors: Vazirian Milad , Movahhedy Mohammad-Reza , Akbari Javad
Published: July 2010

Desktop and miniaturized machine tools are a new trend in small scale and customized manufacturing. The performance of these machines in terms of their energy consumption, machining fluid consumption and their precision have been investigated in the literature, but the effect of miniaturization on static deflection, stability against chatter and the resulting surface error has not been studied. In this paper, the performance of the desktop milling machine tool in terms of their static and dynamic form errors is studied. The performance of a miniature milling machine used for end milling of a typical workpiece is compared with a similar machine of conventional size through dimensional analysis and numerical modeling. The error of the surface finish generated is predicted and verified through simulation.
Non-Rigid Behavior Prediction Based on Styling Data for Evaluation of Perceived Quality
Authors: Wagersten Ola , Wickman Casper , So¨derberg Rikard
Published: July 2010

In the automotive industry it is of great importance to manage the impact of part and assembly variation as it affects aesthetical aspects of the final Perceived Quality, such as the appearance of flush, parallelism and gaps in split-lines. By using a CAT (Computer Aided Tolerancing) software simulating tolerances, in combination with a high-end visualization tool, evaluations are made to judge a predicted outcome of the final Perceived Quality. When a new styling concept needs to be evaluated the data used for analysis and visualization will be less mature and the fact that several vehicle components are non-rigid will further complicate the realization of non-nominal visualization. The deformation behavior of non-rigid components is dependent on several parameters such as part shape, position of reference points, flanges, reinforcements etc. Such information is most likely not available when evaluating a new styling concept, represented only by a surface skin. This paper discusses the possibility to use this limited information, defined as styling data, as a basis when performing non-nominal visualization and evaluation of Perceived Quality based on deformable non-rigid components. The insufficient information is supplemented by collecting and comparing data from prior projects to enable non-rigid behavior prediction of components as such.
Experimental Investigations of Performance and Emission Characteristics of Moringa Oil Methyl Ester and Its Diesel Blends in a Single Cylinder Direct Injection Diesel Engine
Authors: Rajaraman Shyamsundar , Yashwanth G. K. , Rajan T. , Siva Kumaran R. , Raghu P.
Published: July 2010

World at present is confronted with the twin crisis of fossil fuel depletion and environmental pollution. Rapid escalation in prices and hydrocarbon resources depletion has led us to look for alternative fuels, which can satisfy ever increasing demands of energy as well as protect the environment from noxious pollutants. In this direction an attempt has been made to study a biodiesel, namely Moringa Oil Methyl Esters [MOME]. All the experiments were carried out on a 4.4 kW naturally aspirated stationary direct injection diesel engine coupled with a dynamometer to determine the engine performance and emission analysis for MOME. It was observed that there was a reduction in HC, CO and PM emissions along with a substantial increase in NOx. MOME and its blends had slightly lower thermal efficiency than diesel oil.
Development and Validation of a Multi-Zone Combustion Model for Predicting Performance Characteristics and NOx Emissions in Large Scale Two-Stroke Diesel Engines
Authors: Lamaris Vasilios T. , Hountalas Dimitrios T. , Zannis Theodoros C. , Glaros Stefanos E.
Published: July 2010

In the present study, an existing multi-zone combustion model has been modified and applied to predict the performance characteristics and the NOx emissions of a large-scale two-stroke diesel engine (i.e. 12.5 MW rated power). Initially, an attempt was made to examine whether the multizone model can predict with sufficient accuracy the main performance parameters of the stationary diesel engine, using input data from the shop tests (i.e. engine speed, fuel consumption and scavenging pressure at different engine loads). Hence, it was verified that the model is capable of describing the main performance characteristics of the engine with satisfactory accuracy (i.e. reference state). Further on, an experimental investigation was conducted on the specific engine, consisting of a series of performance and NOx emissions measurements that were conducted at constant speed and at three different engine loads. Then, the proposed model was applied at the present engine condition to evaluate its ability to predict the combustion mechanism using the measured cylinder pressure trace as basis for comparison. Furthermore, the predicted engine out NOx emissions were compared to measured values to examine if the model can estimate at least qualitatively the effect of engine load on them. From this combined theoretical and experimental analysis is revealed that the developed model is capable of adequately predicting both engine performance and NOx emissions of large-scale two-stroke diesel engines.
Dynamic Effects Under Gaseous Detonation and Mechanical Response of Piping Structures
Authors: Kuznetsov M. , Lelyakin A. , Breitung W. , Grune J. , Sempert K. , Friedrich A.
Published: July 2010

A series of experiments and numerical simulations on hydrogen detonations in piping geometry was performed in order to reproduce the worst case scenario regarding the maximum internal pressure load and integrity of a piping structure to detonation pressure loads. To reproduce different scenarios of the detonation process and different pressure loads on the piping structure, nitrogen-diluted hydrogen-oxygen mixtures were studied. The mechanical response of 12.5-m long austenitic steel pipe with an outer diameter of 510 mm and wall thickness of 15 mm was investigated as well. A novel 1-D CFD code with a prescribed flame velocity model was used for the numerical simulation of the deflagration to detonation transition (DDT) and for the calculation of pressure loads at various positions along the tube. Different gas dynamic effects such as precursor shock waves and shock reflections on the maximum pressure were investigated in the calculations. Maximum pressure load of a pipe with two end flanges can be achieved near the DDT point and at the tube ends. Dilution of the hydrogen-oxygen mixture with nitrogen leads to a reduction of the mixture reactivity and to an increase of the run-up distance to the DDT point. In this case so called “late detonation initiation”, a cumulative effect of precursor shock wave, detonation ignition and shock wave reflections, can occur near the tube end. It produces extremely high pressure loads which can be 10 times higher than the CJ-detonation pressure of the initial gas mixture. Such scenarios of the combustion process have been experimentally reproduced with detailed pressure and strain measurements along the test tube.
A Method for Clustering the Output of Automated Concept Generators
Authors: Poppa Kerry R. , Stone Robert B.
Published: July 2010

Early in the design process, it is desirable to produce a large number of potential solutions. However, completely exploring a problem’s solution space is an unreasonable expectation for an unaided designer or design team. Computational tools have emerged to help designers more fully explore possible solutions during conceptual design. These automated concept generators use knowledge from existing designs and the desired functionality of the new product to suggest solutions. Existing automated concept generation methods produce many candidate solutions, but often provide the designer with unmanageably large sets of solutions. Techniques are needed to organize the set of concepts into smaller groups, more easily parsed by the human designer. This work proceeds from the hypothesis that the utility of automated concept generators can be enhanced if their output is first sorted into clusters of similar concepts. A general method is developed to estimate a variety of attributes, related to customer needs, and design for “X” parameters, for each concept based on data stored in a design repository. A technique for aggregating parameter estimates into a vector of concept attributes is discussed and a method for clustering concepts based on attribute vectors is presented. Finally, a case study showing the clustering method applied to a simple design problem with design for manufacture and assembly constraints is detailed. The proposed methodology allows designers to make a first pass rejection of concepts with undesirable attributes and suggests a group of concepts that merit further study. The number of concepts that must be independently evaluated is reduced increasing the usability of automated concept generators.
Effect of Selective Accommodation on Soot Aggregate Shielding in Time-Resolved Laser-Induced Incandescence Experiments
Authors: Daun K. J.
Published: July 2010

Time-resolved laser-induced incandescence (TiRe-LII) is an emerging diagnostic for characterizing primary-particle size distributions within soot-laden aerosols. This measurement requires an accurate model of heat conduction between the laser-energized soot and the surrounding gas, which is complicated by fractal-like structure of soot aggregates since primary particles on the aggregate exterior shield the interior from approaching gas molecules. Previous efforts to characterize aggregate shielding using Direct-Simulation-Monte-Carlo (DSMC) analysis assume a monatomic gas and a Maxwell kernel, which is known to be a poor representation of true gas/surface scattering physics. This paper investigates how selective thermal accommodation into the translational and rotational modes of the gas molecule influences the aggregate shielding effect using the Cercignani-Lampis-Lord (CLL) kernel and thermal accommodation coefficients derived from molecular dynamics simulations.
Conceptual Design of a Variable Configuration Articulated Tracked Vehicle
Authors: Lin Jun , Goldenberg Andrew A.
Published: July 2010

This paper presents a conceptual design for variable configurations articulated tracked vehicle (LMA) [1] that has active adaptability to suit for rough and unpredictable terrains, including stairways, obstacles and ditches. The active terrain adaptability is performed by a track configuration-controlling mechanism which is a simple 3-bar cam mechanism consisting of 2 moving elements and a cam fixedly mounted on the vehicle’s chassis. The mechanism has three functions: (1) ensuring the center of a planetary wheel mounted on the end of the track configuration-controlling mechanism to move along an exactly elliptic path; (2) providing the tracks with a continuously invariable spring force to tension tracks; and (3) changing and adjusting the center of gravity of the robot system to prevent it turning over from stairs.