bluuebunny/crossref_metadata_2025 huggingface dataset:
A Thermostatically Controlled Developing and Fixing Tank
Authors: HIME J. M.
Published: May 2008

Abstract— An inexpensive thermostatically controlled developing and fixing tank for X‐ray darkroom use is described.

Résumé— On décrit une cuve thermostatique pour le développement et le fixage en chambre noire radiologique.

Zusammenfassung— Es wird ein billiger thermostatisch geregelter Entwicklungs‐ und Fixierungs‐tank für die Röntgendunkelkammer beschrieben.
The Estimation of Blood Urea by the Xanthydrol Reaction
Authors: BOWDEN R. S. T.
Published: May 2008

Abstract— A simple inexpensive test is described for the estimation of blood urea. The Xanthydrol turbidity reaction is quickly determined and is a reasonably accurate method for quantitative estimation of nitrogen retention in chronic nephritis cases.

Résumé— Un test simple et économique est décrit pour la recherche et le dosage de l'urée sanguine. L'opacité de la réaction du Xanthydrol est rapidement déterminée et constitue une méthode assez précise pour l'estimation quantitative de la rétention azotée dans les cas de néphrite chronique.

Zusammenfassung— Es wird ein einfacher, billiger Test für die Blutharnstoff bestimmung beschrieben. Die Xanthydrol‐Trübungsreaktion ist schnell durchführbar und ist eine ziemlich direkte Methode zur quantitativen Bestimmung der Stickstoffretention bei Fällen von chronischer Nephritis.
Feeding Unusual Pets
Authors: FISHER LESTER E.
Published: May 2008

Abstract— A review is presented of some of the problems concerned in the nutrition and dietary requirements of unusual pets. The species discussed are the budgerigar, canary, parrot, monkey, rabbit, guinea pig, mouse, rat, hamster, skunk, snake, turtle, ocelot and alligator.

Résumé— Revue de quelques‐uns des problèmes entrant en ligne de compte dans la nutrition et les exigences diététiques de certains anirnaux familiers peu courants. Les espèces envisagées sont la perruche ondulée, le canari, le perroquet, le singe, le lapin, le cobaye, la souris, le rat, le hamster, le skunk, le serpent, la tortue, l'ocelot et l'alligator.

Zusammenfassung— Es wird eine Übersicht über einige Probleme gegeben, die mit der Ernährung und den Diätvorschriften ungewöhnlicher Haustiere zusammenhängen.
Gross pulmonary thrombosis in a greyhound
Authors: Baines E. A. , Watson P. J. , Stidworthy M. F. , Herrtage M. E.
Published: May 2008

A two‐year‐old greyhound was presented with progressive dyspnoea. Radiography showed a hypovascular lung pattern with hyperlucent lung fields and echocardiography revealed a large thrombus in the main pulmonary artery. Blood results showed azotaemia and marked hypoalbuminaemia. The dog's clinical condition continued to deteriorate and it was euthanased. Postmortem examination confirmed the presence of the pulmonary thrombus and revealed idiopathic membranous glomerulonephritis.
Deficit Estimation and Welfare Effects after the 1994 Fiscal Reform in China: Evidence from the County Level
Authors: Zhang Pengfei , Shih Victor
Published: May 2008

Using simple statistical analysis of county‐level budgetary data from across all of China's counties, the present paper examines whether the post‐1994 fiscal decentralization has affected redistribution at the county‐level. The new fiscal system has been less able to narrow inter‐county dispersion in fiscal imbalances than the old one, even after taking intergovernmental transfer payments into account. Although with the post‐1994 system there has been a modest increase in per capita welfare spending in all counties on average, much of the new‐found fiscal resources have been spent on salary and administrative expenses rather than spending on public goods. Therefore, it is imperative that the reform of China's tax system is intensified.
Impacts of Cultivated Land Conversion on Environmental Sustainability and Grain Self‐sufficiency in China
Authors: Tan Shuhao
Published: May 2008

Using provincial data, the present paper examines the impact of cultivated land conversion on agriculture and the environment. It is found that the grain production center is gradually moving towards more fragile and water scarce areas, putting more pressure on the environment. Land conversion caused large losses in ecosystem service values in the 1990s, but large scale ecological restoration programs have been implemented since 2000 to compensate for such losses. The ecological restoration programs are concentrated in regions with relatively low land productivity, whereas cultivated land conversion usually takes place in areas with relatively high land productivity. Newly‐cultivated land, especially that in areas marginally suit for agricultural production, is likely to have much lower productivity levels than the original cultivated land. Because the stock of potentially cultivable land is almost exhausted, China's grain self‐sufficiency policy can only be maintained by preserving the available stock of arable land and increasing its productivity in a sustainable way.
How Will China Move towards Becoming a Low Carbon Economy?
Authors: Zhuang Guiyang
Published: May 2008

China is facing increasing pressure from the international community to curb its greenhouse emissions. The next 15–20 years are important for China's social and economic development, but this is also a key period for controlling global greenhouse gas emissions. In considering the development path of China's economy, policy‐makers are confronted by the issue of global climate change. Reducing carbon emissions is now a worldwide task. For China, opportunities and challenges coexist. Post‐Kyoto climate regime must provide incentives for China's transition to becoming a low carbon economy based on the principle of common but differentiated responsibilities.
An Antibody to the Aggregated Synthetic Prion Protein Peptide (PrP106–126) Selectively Recognizes Disease‐Associated Prion Protein (PrPSc) from Human Brain Specimens
Authors: Jones Michael , Wight Darren , McLoughlin Victoria , Norrby Katherine , Ironside James W. , Connolly John G. , Farquhar Christine F. , MacGregor Ian R. , Head Mark W.
Published: May 2008

Human prion diseases are characterized by the conversion of the normal host cellular prion protein (PrPC) into an abnormal misfolded form [disease‐associated prion protein (PrPSc)]. Antibodies that are capable of distinguishing between PrPC and PrPSc may prove to be useful, not only for the diagnosis of these diseases, but also for a better understanding of the molecular mechanisms involved in disease pathogenesis. In an attempt to produce such antibodies, we immunized mice with an aggregated peptide spanning amino acid residues 106 to 126 of human PrP (PrP106–126). We were able to isolate and single cell clone a hybridoma cell line (P1:1) which secreted an IgM isotype antibody [monoclonal antibody (mAb P1:1)] that recognized the aggregated, but not the monomeric form of the immunogen. When used in immunoprecipitation assays, the antibody did not recognize normal PrPC from non‐prion disease brain specimens, but did selectively immunoprecipitate full‐length PrPSc from cases of variant and sporadic Creutzfeldt–Jakob disease and Gerstmann–Straussler–Scheinker disease. These results suggest that P1:1 recognizes an epitope formed during the structural rearrangement or aggregation of the PrP that is common to the major PrPSc types found in the most common forms of human prion disease.
Fundus autofluorescence related to retinal morphological and functional changes in idiopathic macular holes
Authors: Wakabayashi Taku , Ikuno Yasushi , Sayanagi Kaori , Soga Kaori , Oshima Yusuke , Tano Yasuo
Published: May 2008

Purpose:  To investigate fundus autofluorescence (FAF) characteristics in relation to morphological and functional features of idiopathic macular hole (IMH).

Methods:  Twenty eyes of 20 consecutive patients with stage 3 or 4 macular holes were included. Fundus autofluorescence images were obtained using the Heidelberg retina angiograph 2, retinal structure was evaluated with 3‐dimensional (3‐D) imaging of Fourier‐domain optical coherence tomography (FD‐OCT), and retinal function was assessed with microperimetry‐1 (MP‐1).

Results:  Markedly increased FAF in the foveal centre corresponding to the macular hole, confirmed with FD‐OCT, was demonstrated in all eyes. A surrounding hypoautofluorescent ring corresponded to the subretinal fluid cuff. The area of relatively reduced FAF around the ring corresponded precisely to retinal oedema. In 15 eyes (75%), a stellate appearance with dark radiating striae was seen in the relatively reduced FAF and was correlated with intraretinal cystic changes in the outer plexiform layer, observed by FD‐OCT. Mean preoperative visual acuity was significantly poorer in eyes without a stellate appearance than in those with a stellate appearance (p = 0.023). The MP‐1 study confirmed impaired retinal function in the macular hole bed and in the area of the fluid cuff and retinal oedema.

Conclusions:  Fundus autofluorescence imaging reflects anatomic changes and represents the dysfunctional retinal area in IMH. The technique provides 2‐D images with 3‐D information on the retinal morphology of this disease.
Endothelial dysfunction in glaucoma
Authors: Resch Hemma , Garhofer Gerhard , Fuchsjäger‐Mayrl Gabriele , Hommer Anton , Schmetterer Leopold
Published: May 2008

Glaucoma is a group of ocular diseases characterized by optic neuropathy associated with loss of the retinal nerve fibre layer and re‐modelling of the optic nerve head, and a subsequent particular pattern of visual field loss. Increased intraocular pressure is the most important risk factor for the disease, but the pathogenesis of glaucoma is not monofactorial. Among other factors, ischaemia and vascular dysregulation have been implicated in the mechanisms underlying glaucoma. The vascular endothelium plays an important role in the regulation of ocular blood flow and pathological alterations of vascular endothelial cells may induce ischaemia and dysregulation. The present review summarizes our current evidence of endothelial dysfunction in glaucoma. This is of interest because endothelial dysfunction is a good prognostic factor for progression in several diseases. Although such data are lacking for glaucoma, endothelial dysfunction may provide an attractive target for therapeutic intervention in open‐angle glaucoma and other vascular disorders of the eye.
Effects of repeated injection of intravitreal triamcinolone on macular oedema in central retinal vein occlusion
Authors: Wang Lili , Song Huping
Published: May 2008

Purpose:  To investigate the effectiveness of repeated injections of intravitreal triamcinolone acetonide (IVTA) in the treatment of macular oedema caused by central retinal vein occlusion (CRVO).

Methods:  Seventeen pseudophakic or aphakic eyes of 17 patients (10 male, seven female) with macular oedema caused by CRVO received a repeat injection of 4 mg IVTA, 16 weeks after the first injection of the same dose. The examination included measurements of best‐corrected visual acuity (BCVA) for distance and central foveal thickness (CFT) by optical coherence tomography (OCT), preoperatively and 1, 2, 3 and 4 months postoperatively. The values were compared by paired‐t test. Side‐effects were monitored.

Results:  BCVA and CFT were not significantly different before initial and repeat injections. Transient improvements of BCVA and CFT were achieved after both injections. At the end of follow‐up, BCVA and CFT were significantly different compared to pre‐injection values in the same group (P = 0.032, 0.049 in the initial‐injection group and P = 0.001, 0.008 in the repeat‐injection group, respectively). However, compared to the initial injection, BCVA measurements were significantly worse at each time‐point (P = 0.043, 0.011, 0.010 and 0.012, respectively) after the repeat injection, as were CFT at 1, 2 and 3 months post‐injection (P = 0.040, 0.015 and 0.025, respectively). The achieved maximum mean intraocular pressures were 20.00 [standard deviation (SD) 2.06] mmHg and 18.56 (SD 3.65) mmHg after the first and repeat injections, respectively. These values were not significantly different (P = 0.467). No other significant adverse events were noted during the study.

Conclusion:  A repeat injection of 4 mg IVTA may not be as effective as an initial injection for the treatment of macular oedema caused by CRVO.
The Educational Impact of a Gantry Crane Project in an Undergraduate Controls Class
Authors: Reynolds Michael C. , Meckl Peter H. , Yao Bin
Published: May 2008

In the fall of 2001 we implemented a new controller design project in our Junior/Senior level controls class in Mechanical Engineering at Purdue University. The old project, which involved the identification and control of a “black box”, failed to challenge and motivate students. Our new project is the design of a controller for the point-to-point motion of a gantry crane system. Student teams modeled the gantry crane and developed a controller to meet several performance specifications. The designs were implemented in Simulink with MATLAB’s Real-Time Workshop. A competition served to further motivate the students. In the end we were very impressed with the great effort the students gave and the quality of their designs. Each group presented their design and most students stayed and asked questions for several hours.
An Instrumental Variable Approach for Continuous-Time Identification of an SI Engine Model for Automatic Controller Design
Authors: Cunningham Patrick J. , Franchek Matthew A.
Published: May 2008

Instrumental variable algorithms are popular for their favorable consistency properties and ease of implementation. In this investigation an algorithm for automatic SI engine idle speed controller design uses and instrumental variable approach to perform system identification. The instrumental variable method employed here identifies the coefficients of a continuous-time model from discretely sampled data. This continuous-time model represents the engine dynamics from the bypass air valve voltage to the engine speed. To implements the identification algorithm, filtered derivative estimators approximate engine speed derivatives and an auxiliary model generates instrumental variables. These calculations are performed at each sample instant and are passed to the recursive formulation of the instrumental variable identification algorithm. Identification is performed utilizing reference step response data. A complete consistency analysis of this algorithm is included for this realization of the instrumental variable algorithm. Automatic controller design is completed based on the identified continuous-time model coefficients. As a result, the controller is parameterized based on the model coefficients and matching the transfer function of the idle speed feedback system to an open loop transfer function which represents the desired transient and steady state performance. The controller is implemented via a bumpless transfer process. Experimental results performed on a 4.6L V-8 fuel injected SI engine demonstrate the automated controller design process and the instrumental variable identification algorithm.
Structural Damage Assessment Using Chaotic Dynamic Interrogation
Authors: Todd Michael , Trickey Stephen , Seaver Mark , Nichols Jonathan , Virgin Lawrence
Published: May 2008

This work considers a new technique for damage detection in vibration-based structural health monitoring. The technique involves exciting a structure with a low-dimensional chaotic input, reconstructing the attractor, and analyzing certain properties of the attractor for the subtle changes which may occur due to damage. Recourse is made to the Kaplan-Yorke conjecture for motivating the technique. The technique is then demonstrated in the laboratory on a beam subject to boundary clamp damage controlled by means of a special elastic clamp. The measurements are made with a special fiber optic strain measurement system whose key performance features are described.
Vibration-Based NDE Technique for Identifying Non-Uniformities in Manufactured Parts With Degeneracies
Authors: Jellison B. J. , Kess H. R. , Adams D. E. , Nelson D. C.
Published: May 2008

A novel method for characterizing non-uniformities in homogeneous precision symmetric parts using pseudo-repeated modal frequencies is discussed in this paper. It is demonstrated that the spacing between pseudo-repeated roots (modal frequencies) in dominantly symmetric manufactured parts is a direct indicator of non-uniformities (i.e. asymmetries) in the stiffness or mass distributions. Smaller differences between split-peaks indicate less non-uniformity, and hence, higher quality-greater precision parts. By establishing a tolerance for precision manufactured parts based on a collection of vibration modal parameter data from acceptable parts for a given process, this work shows that poorly manufactured parts with density discontinuities (e.g. inclusions, voids) can be identified based on the degree to which their pseudo-repeated roots are separated. A simple low-order lumped parameter model is used to develop this technique analytically and acceleration response data from impact vibration tests on deep drawn hemispherical shells is used to verify the validity of the approach experimentally.
Open Platform for the Integration of Monitoring Applications
Authors: Kahmen Andreas , Weck Manfred
Published: May 2008

Process and machine tool condition monitoring are the keys to an increasing degree of automation and consequently to an increasing productivity in manufacturing. The realisation of monitoring functionality demands an extension of the control system. The prerequisite for these extensions are open interfaces in the NC-kernel. Nowadays controls with open NC-kernel interfaces are available on the market. However these interfaces are vendor specific solutions that do not allow the reuse of monitoring software in different controls. To overcome these limitations a platform with vendor neutral open real-time interface for the integration of monitoring functionality into the NC-kernel is presented in this paper. Additionally two realisations of the integration platform for different target systems are described.
Application of an Imaging System to Study Machining Mist Formation via an Atomization Mechanism
Authors: Ju C. , Sun J. , Michalek D. J. , Sutherland J. W.
Published: May 2008

Airborne inhalable particulate in the workplace represents a significant health hazard. One of the primary sources of this particulate is mist produced through the application of cutting fluids in machining operations. One of the important mechanisms for the production of cutting fluid mist is the atomization mechanism. In this paper, atomization is studied by applying cutting fluid to a rotating workpiece such as found in turning. An imaging system is presented for the study of the atomization mechanism. The imaging system extends the size measurement range typically achievable with aerosol sampling devices to consider larger particles. Experimental observations from the imaging system reveal that workpiece rotation speed and cutting fluid flow rate have significant effects on the size of the droplets produced by the atomization mechanism. With respect to atomization, the technical literature describes models for fluid interaction with the rotating workpiece and droplet formation via drop and ligament formation modes. Experimental measurements are compared with model predictions. For a range of rotation speeds and fluid application flow rates, the experimental data is seen to compare favorably with the model predictions.
Dynamic Compensation of Cutting Forces Measured From the Spindle Integrated Force Sensor System
Authors: Park Simon S. , Altintas Y.
Published: May 2008

This paper presents a dynamically compensated Spindle Integrated Force Sensor (SIFS) system to measure cutting forces. Piezo-electric force sensors are integrated to the stationary spindle housing. The structural dynamic model between the cutting forces acting on the tool tip and the measured forces at the spindle housing is identified. The system is first calibrated to compensate the influence of spindle run-out and unbalance at different speeds. Using both the cutting force and acceleration sensor signals measured at the spindle housing, a Kalman Filter is designed to filter the influence of structural modes on the force measurements. The frequency bandwidth of the proposed sensor system is expanded from 300 Hz to about 800 Hz with the proposed sensing and the signal processing method.
Engineering in Rehabilitation: A Brief History of Engineering Contributions to the Science, Art and Practice of Rehabilitation
Authors: Brubaker Clifford E. , Childress Dudley S.
Published: May 2008

It seems appropriate to begin by acknowledging that the evolution of a field or discipline is subject to invention and discovery but, perhaps, even more so to political and social forces. It is also worth noting that advances proceed erratically for these same reasons. This is certainly the case for Engineering and its sub-disciplines of Bioengineering and Rehabilitation Engineering. Hopefully this will become evident in the following discourse.
Evolution of Microchannel Flow Passages: Thermohydraulic Performance and Fabrication Technology
Authors: Kandlikar Satish G. , Grande William J.
Published: May 2008

This paper provides a roadmap of development in the thermal and fabrication aspects of microchannels as applied in the microelectronics and other high heat-flux cooling applications. Microchannels are defined as flow passages that have hydraulic diameters in the range of 10 to 200 micrometers. The impetus for microchannel research was provided by the pioneering work of Tuckerman and Pease [1] at Stanford University in the early eighties. Since that time, this technology has received considerable attention in microelectronics and other major application areas, such as fuel cell systems and advanced heat sink designs. After reviewing the advancement in heat transfer technology from a historical perspective, advantages of using microchannels in high heat flux cooling applications is discussed, and research done on various aspects of microchannel heat exchanger performance is reviewed. Single-phase performance for liquids is expected to be still describable by the conventional equations; however the gas flow may be influenced by the rarefaction effects. Two-phase flow is another topic that is still under active research. The evolution of research into microchannel heat sinks has paralleled the advancements made in microfabrication technology. The earliest microchannels were built using anisotropic wet chemical etching techniques based on alkali solutions. While this method has been exploited successfully, it does impose certain restrictions on silicon wafer type and geometry. Recently, anisotropic dry etching processes have been developed that circumvent these restrictions. In addition, dry etching methods can be significantly faster and, from a manufacturing standpoint, create fewer contamination and waste treatment problems. Advances in fabrication technology will continue to fuel improvements in microchannel heat sink performance and cost for the foreseeable future. Some fabrication areas that may spur advances include new materials, high aspect ratio patterning techniques other than dry etching, active fluid flow elements, and micromolding.
Effect of Physiological Parameters on the Temperature Distribution of a Layered Head Model
Authors: Ley Obdulia , Bayazitoglu Yildiz
Published: May 2008

Brain temperature control is important in clinical therapy, because moderate temperature reduction of brain temperature increases the survival rate after head trauma. A factor that affects the brain temperature distribution is the cerebral blood flow, which is controlled by autoregulatory mechanisms. To improve the existing thermal models of brain, we incorporate the effect of the temperature over the metabolic heat generation, and the regulatory processes that control the cerebral blood perfusion and depend on physiological parameters like, the mean arterial blood pressure, the partial pressure of oxygen, the partial pressure of carbon dioxide, and the cerebral metabolic rate of oxygen consumption. The introduction of these parameters in a thermal model gives information about how specific conditions, such as brain edema, hypoxia, hypercapnia, or hypotension, affect the temperature distribution within the brain. Existing biological thermal models of the human brain, assume constant blood perfusion, and neglect metabolic heat generation or consider it constant, which is a valid assumption for healthy tissue. But during sickness, trauma or under the effect of drugs like anesthetics, the metabolic activity and organ blood flow vary considerably, and such variations must be accounted for in order to achieve accurate thermal modeling. Our work, on a layered head model, shows that variations of the physiological parameters have profound effect on the temperature gradients within the head.
Finite Element Simulation of Cooling of Realistic 3-D Human Head and Neck
Authors: Dennis Brian H. , Eberhart Robert C. , Dulikravich George S. , Radons Steve W.
Published: May 2008

Rapid cooling of the brain in the first minutes following the onset of cerebral ischemia is a potentially attractive preservation method. This computer modeling study was undertaken to examine brain-cooling profiles in response to various external cooling methods and protocols, in order to guide the development of clinical cooling devices. The criterion of successful cooling is the attainment of a 33.0°C average brain temperature within 30 minutes of treatment. Comparison of the finite element model results with a formal mathematical solution, give confidence that the simulation methods are sound. The cooling simulations considered to date all indicate that no one means of external cooling of the head or neck is sufficient to cool the brain in a reasonable period of time (30 minutes). Neither ice packs applied to head or neck, or cooling helmets can satisfy the 33.0°C target temperature specification. This central conclusion of insubstantial cooling is supported by the modest enhancements reported in experimental investigations of externally applied cooling. The key problem is overcoming the protective effect of warm blood perfusion, which reaches the brain via the uncooled carotid arterial supply and effectively blocks the external cooling wave from advancing to the core of the brain. This suggests that other cooling means should be explored requiring a realistic simulation of cooling of other pertinent parts of the human anatomy.
Simulation and Analysis of Transient Fuel Cell System Performance Based on a Dynamic Reactant Flow Model
Authors: Pukrushpan Jay T. , Peng Huei , Stefanopoulou Anna G.
Published: May 2008

Fuel cell stack systems are under intensive development by several manufacturers since they complement heat engines and reduce the ubiquitous dependence on fossil fuels and thus have significant environmental and national security implications. To compete with ICE engines, however, fuel cell system must operate and function at least as well as conventional engines. Transient behavior is on of the key requirements for the success of fuel cell vehicles. The fuel cell system power response depends on the air and hydrogen feed, flow and pressure regulation, and heat and water management. During transient, the fuel cell stack control system is required to maintain optimal temperature, membrane hydration, and partial pressure of the reactants across the membrane in order to avoid degradation of the stack voltage, and thus, efficiency reduction. In this paper, we developed a fuel cell system dynamic model suitable for control study. The transient phenomena captured in the model include the flow characteristics and inertia dynamics of the compressor, the manifold filling dynamics (both anode and cathode), and consequently, the time-evolving reactant partial pressures, and membrane humidity. The effects of varying oxygen concentration and membrane humidity on the fuel cell voltage were included. Simulation results are presented to demonstrate the model capability.
Experimental Study of Direct Contact Condensation in the Presence of Noncondensable Gas
Authors: Xu Yiban , Revankar Shripad T. , Ishii Mamoru
Published: May 2008

A series of direct contact condensation tests of mixture of saturated steam and nitrogen has been carried out in a subcooled pool of water. Nitrogen is used as the noncondensable gas. A mixture of nitrogen and steam is discharged into the subcooled water pool through a vertical nozzle. The apparatus is equipped with appropriate instruments and flow visualization. Pre-heaters and super-heaters are used to heat up nitrogen and steam before they are mixed. Tests have been preformed with variations of the liquid temperature, system pressure, nozzle size and the concentration of noncondensable gas. Images of bubble behaviors are captured with high speed video camera and downloaded into a PC in digital format. Information on bubble size variation and formation frequency is obtained from the image analysis. Detaching bubble size, surface area and frequency are correlated with the various dimensionless numbers.
Experimental and Numerical Studies of Heat Transfer in Human Uteri During Cryoablation
Authors: Chen Jim S. , Agnissey Kevin , Wolfson Marla , Philips Charles , Shaffer Thomas
Published: May 2008

This paper presents experimental and numerical studies of transient heat transfer inside the uterus during application of a PFC (perfluorochemical) fluid into the endometrium cavity in order to achieve cryoablation. The numerical prediction is based on a 1-D finite difference method of the bio-heat equation using the Crank Nicolson scheme. The numerical method is first validated by a 1-D physical model by measuring temperature history at several locations within a silicone rubber sheet. Good agreement, thus positive predictability, was obtained by comparing numerical predictions with the experimental data obtained from eight intact, hysterectomized uteri during cryoablation.
Numerical Investigations of Double-Species Slurry Flow in a Straight Pipe Entrance
Authors: Ling J. , Lin C. X. , Ebadian M. A.
Published: May 2008

Because of the complexity of multiphase slurry flow, most experiments and simulations described in the open literature are focused on single-species solid-liquid flow. In this paper, a Eulerian granular multiphase (EGM) model is introduced to make the numerical investigations in the entrance region of a straight pipe for a double-species slurry flow. In order for the study to obtain the numerical solution in fully developed turbulent flow, the k–ε turbulent model was used with the Eulerian granular multiphase model. An O-type structured grid was chosen to discretize the entire computation domain, and a control volume finite difference method (CVFDM) was applied in the governing equations. Some simulation results are compared with the authors’ experimental data to validate the numerical investigation. These numerical results for the pressure gradients are found to be in good agreement with the experimental data. It is very difficult to obtain some important flow characteristics in the double-species slurry flow by experiments; therefore, the volume fractions (or concentrations) of solids, the average velocity distributions, and the turbulent kinetic energy and dissipation rates of water in the pipe entrance will be displayed and analyzed in the numerical investigations, which have seldom been reported in the open literature.
Numerical Simulation of Black Liquor Spray Characteristics
Authors: Foust Thomas D. , Hamman Kurt D. , Detering Brent A.
Published: May 2008

The performance and capacity of Kraft recovery boilers is sensitive to black liquor velocity, droplet size and flow distribution in the furnace. Studies have shown that controlling droplet size and flow distribution improves boiler efficiency while allowing increased flight drying and devolatilization, and decreased carryover. The purpose of this study is to develop a robust two-phase numerical model to predict black liquor splashplate nozzle spray characteristics. A three-dimensional time dependent numerical study of black liquor sheet formation and sheet breakup is described. The volume of fluid (VOF) model is used to simulate flow through the splashplate nozzle up to initial sheet breakup and droplet formation. The VOF model solves the conservation equations of volume fraction and momentum utilizing the finite volume technique. Black liquor velocity, droplet size and flow distribution over a range of operating parameters are simulated using scaled physical models of splashplate nozzles. The VOF model is compared to results from a flow visualization experiment and experimental data found in the literature. The details of the simulation and experimental results are presented.
An Investigation of Multicomponent Droplet Vaporization in Fluidized Catalytic Cracking Risers
Authors: Bowman B. J. , Zhou C. Q. , Chang S. L.
Published: May 2008

Fluidized Catalytic Cracking (FCC) oil refining technology converts heavy feed oil into lighter, more valuable components using hot catalysts in a riser reactor. The interphase mixing, vaporization, and chemical reactions are the controlling processes inside the FCC riser. The interactions between the feed oil spray and the gas/solid flow determine the final products of the cracking process, and ultimately the profitability of the FCC unit. A three-phase reacting flow computational fluid dynamic (CFD) code, ICRKFLO, has been developed for the simulation of FCC riser flows. In this study, ICRKFLO is used to simulate a low profile FCC riser. A low profile riser has a shorter residence time than standard FCC risers, and the modeling of the droplet vaporization process is of great importance. Because feed oil is composed of many hydrocarbon components, each of which vaporize at a different temperature, a new vaporization model is developed to include multicomponent vaporization of a droplet. The model allows the boiling point temperature of the droplets to vary as the vaporizing droplet loses mass to the gaseous phase. Comparison between the existing and new models shows a significant change in gasoline yields at the riser exit.
Experimentally Identifying the Transfer Function of an Electromechanical System
Authors: Layton Richard A. , Grigg Clifford
Published: May 2008

An experiment is developed in which the instructor demonstrates the acquisition of frequency response data for an electromechanical system (an X-Y recorder). Students are given copies of the acquired data, from which they create an amplitude response plot and develop a transfer function for the system. Using a simple optimization routine, students tweak the model until the predicted amplitude response most closely matches the experimental data. The model is refined further by adding a zero to the transfer function. Students compare the predictions of their models to the experimental data and answer related questions on a lab worksheet, all within one three-hour lab period. In this paper, the apparatus, demonstration, data reduction, system identification, and results are described. A videotaped demonstration of the experiment, sample data, and the lab handout and worksheet are available online at www.rose-hulman.edu/ES205/labs.html. In future work, the experiment will be modified to measure phase response.
A Novel Structure for Measurement and Instrumentation Courses
Authors: Lauderbaugh Saunders L. Ken
Published: May 2008

This paper presents a new approach to the design of undergraduate measurement and instrumentation courses. Measurement and instrumentation courses are typically taught as a combination of lab procedures and measurement technology, with a bit of statistics thrown in. These courses are typically structured as a laboratory supporting a lecture course. A new approach to this course has been developed and implemented. In this new approach, a combination of lectures and independent research support independent laboratory experiments coupled with rigorous technical writing assignments. The new instructional design consists of a series of lectures conducted during the first half of the course. These lectures cover general topics needed for most of the laboratories. Students are given reading/research and homework assignments throughout the course to cover the “technology” of sensors and measurement systems. These lectures and assignments support the conducting of 11 open ended labs and a term project: each requiring an extensive lab report. This new approach is proving to be very effective. The interest level of the students has improved greatly. Instead of simply applying a known sensor to a given problem, the students are now able to identify a measurement problem, determine and research appropriate sensors, design an experimental system, document results and prepare a technical argument. A detailed discussion of this approach is included. Student feedback and anecdotal evidence are also included.
Neural Network Based Intelligent Control and PID Control of a Magnetic Levitation System
Authors: Garg Devendra P. , Gulati Navneet
Published: May 2008

In order to control a system effectively, the system must be modeled accurately. Frequently, the non-linearities present in system dynamics make the control task difficult. Sometimes it is a real challenging task to come up with a true dynamic model of the system. To appreciate the control complexities, a Magnetic Levitation (ML) System [1] is selected for laboratory demonstration purposes. The magnetic levitation system, wherein the primary objective is to balance a metallic ball in a magnetic field, is highly non-linear [2] by its very nature. For this paper, a dynamic model was derived for such a system and various control techniques were designed and applied and the system performance was compared. A neural network based controller was developed to control the system. Such controllers are particularly useful in those cases, where the mathematical model of the system may not be available. Proportional (P), and Proportional plus Integral plus Derivative (PID) controllers were the other controllers used for the study, and their performances were compared with the neural net work based controller.
The Design and Modeling of a Liquid-Propellant-Powered Actuator for Energetically Autonomous Robots
Authors: Barth Eric J. , Gogola Michael A. , Wehrmeyer Joseph A. , Goldfarb Michael
Published: May 2008

This paper describes the design of a liquid-propellant-powered hot-gas actuator appropriate for human-scale power-autonomous robots. The motivation for this work is the development of a lightweight actuation system with system energy and power densities significantly greater than a DC motor and battery combination. The proposed design of a liquid-fueled actuator is presented, followed by a thermodynamic model of the system. A single-degree of freedom manipulator prototype is presented, and closed-loop tracking control of the liquid-fueled actuator is demonstrated. The measured energy density of the system is presented, and this experimental result is followed by a discussion that correlates the theoretical energy density predicted by the model with the measured energy density of the prototype. The analysis presented in the discussion section indicates that heat flow in the uninsulated experimental prototype constitutes a significant loss of energy, and that if properly insulated, the system should demonstrate an energy density approaching the theoretically predicted case.
Hybrid Fuzzy PID Control of Hydraulic Robot
Authors: Liu Rong , Wang Xuanyin , Huang Xuchu
Published: May 2008

This paper presents a fuzzy tracking control methodology for hydraulic control system of robot with generalized pulse modulation (GPCM) control by combining the merits of fuzzy logic and conventional linear control theory. The hydraulic control systems with GPCM control have the high nonlinearity and uncertain dynamics, therefore the simple linear or nonlinear differential equations cannot sufficiently represent corresponding practical system. The designed controllers based on the model cannot guarantee the good performance such as stability and robustness. A hybrid of fuzzy and PID control algorithm is proposed as the solution. The control algorithm is separated into two parts: fuzzy control and PID control. The fuzzy controller is used to control the piston when the piston is near the desired position, and PID controller is applied when the piston is far away the target position. The hybrid fuzzy PID is implemented on computer and applied to control the arms of hydraulic robot with GPCM control. The results from the experiments show that the proposed hybrid fuzzy PID control has good performance.
Optimization of Advanced Engine Controls for Conventional Vehicles: A Driving Cycle Perspective
Authors: Delagrammatikas George J. , Assanis Dennis N.
Published: May 2008

A controls optimization methodology for advanced diesel engines, as they are utilized in a specific driving cycle, is addressed in this work. The technique illustrated here accounts for realistic engine use regimes encountered during the FTP driving schedule and finds the maximum foreseeable fuel economy improvement, with the introduction of advanced technologies, to a baseline engine design. Outputs from the optimization procedure are analyzed from a numerical standpoint, yielding insights into the general topology of the engine’s design domain. Control variable histories through the specified driving cycle are determined and discussed with specific regard to the thermodynamic mechanisms producing the associated fuel economy improvements. Guidelines for the practical design of engine components, along with the assumptions made for these studies, are detailed. These techniques are directly applicable to other types of automotive internal combustion engines, vehicles, and driving patterns.
Power Split CVT Modeling With Spool Valve Actuation
Authors: Samuels H. Bernard , Wagner John R. , Setlur Pradeep , Dawson Darren M.
Published: May 2008

New stringent emission regulations are requiring automotive engineers to develop vehicles featuring multiple energy sources and innovative drivetrain components. One such innovation is the continuously variable transmission (CVT) which offers a continuum of variable gear ratios for greater efficiency and elimination of unwanted jerks in comparison to fixed gear transmissions. The power split CVT configuration offers both fixed gearing and adjustable pulleys to satisfy the torque/speed demands. Spool valves regulate the hydraulic fluid to actuate the CVT’s primary and secondary sheaves for gear ratio manipulation based on the belt’s tension requirements. To fully support the evaluation of various powertrain configurations and control algorithms, a design tool must be developed which characterizes the complete powertrain system. In this paper, a power split CVT will be mathematically modeled and analyzed. Dynamic models will be introduced for the transmission, driveline, and chassis with attention focused on the CVT pulleys and hydraulics. Representative numerical results will be presented and discussed to quantify the performance of the power split CVT and sheave actuation for prescribed driving maneuvers.
Identification of a Longitudinal Human Driving Model for Adaptive Cruise Control Performance Assessment
Authors: Lee Kangwon , Peng Huei
Published: May 2008

The main purpose of this paper is to develop a longitudinal human driving model that is accurate enough for the performance evaluation of adaptive cruise control systems. Six driver models were evaluated based on selected data from two vehicle motion databases—the SAVME database and the ICCFOT database, both created at the University of Michigan Transportation Research Institute (UMTRI). Among the models we evaluated, the Gipps’ model was found to be the most promising and was further analyzed. A modified version of the model was suggested and evaluated. The modified model was implemented in a microscopic traffic simulator and was found to produce results that agree with macroscopic traffic behavior very well.
Steady-State Heat Transfer Modeling of a Calorimeter Measurement Chamber
Authors: Aviles-Ramos Cuauhtemoc , Rudy Clifford
Published: May 2008

The steady-state heat transfer in a calorimeter measurement chamber is modeled assuming that the sample is a generic nuclear material container filled with plutonium oxide powder. The measurement chamber is composed of nine solid materials and air. The heat transfer model includes natural convection in the plutonium oxide porous matrix, natural convection in the air space on top of the plutonium oxide powder, and heat conduction in the different solid parts of the measurement chamber and the heat flux sensor. The problem is treated as a conjugate heat transfer problem defined by a system of 24 partial differential equations coupled at the interfaces of the materials that form the measurement chamber. A computational fluid dynamics software is used to generate the grid and obtain the solution. The simulation results provide estimates of operational temperatures and heat losses that are of interest in the design of calorimeters.
Numerical Analysis of Heated Soil Vapor Extraction System
Authors: Jadhav R. S. , Amano R. S. , Jatkar J. , Lind R. J.
Published: May 2008

An innovative and highly effective technique for remediation of soil has been developed—Heated Soil Vapor Extraction (HSVE), which is one of essential technologies that quickly and effectively remediates soil that is contaminated with organic compounds. The system efficiently uses the principles of heat transfer and diffusion to eliminate organic compounds from the soil. It basically consists of a high temperature heat source and a sink to take away the vaporized compounds in the presence of high temperature in the soil. A numerical study has been conducted to further strengthen the fact that the system is very effective, by actually modeling soil with system. Finite Element Analysis software ANSYS® has been used for the purpose of analysis. Such analysis will help environmental science and give new dimensions to soil remediation processes to clean soil off volatile organic compounds so that they can be carried out quickly, efficiently and economically.
Combined Heat and Mass Transfer in Porous Media Heat Exchanger
Authors: Druma Adriana M. , Alam Khairul M.
Published: May 2008

A numerical and experimental study of heat and mass transfer has been carried out for an energy recovery ventilator with a porous media heat exchanger. The energy recovery ventilator selected for this study has a rotary periodic heat exchanger that can transfer heat and moisture from one air stream to another. Such heat exchangers can be operated with high effectiveness by using a low-cost porous matrix as the heat exchanger medium. The influence of porosity in the matrix has been studied numerically and the performance of the energy recovery ventilator in recovering both heat and moisture has been modeled.