bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Wall Roughness on Particle Velocities in a Turbulent Channel Flow
Authors: Benson Michael , Tanaka Tomohiko , Eaton John K.
Published: May 2005

Experimental measurements using a laser Doppler anemometer (LDA) system have been performed on 150μm dense glass particles in a fully developed downward channel flow in air. Tests were conducted in smooth, rough development, and fully rough wall conditions with a channel Reynolds number of 13,800, corresponding to a centerline gas phase velocity of 10.5m∕s with a dilute loading of particles of 15% by mass fraction. Velocities were measured and statistics compared to see the nature of the effects of the wall roughness in a rebuilt channel facility originally used for important works including Kulick, Fessler, and Eaton, (1994, “Particle Response and Turbulence Modification in Fully-Developed Channel flow,” J. Fluid Mech., 277, pp. 109–134) and Paris (2001, “Turbulence Attenuation in a Particle-Laden Channel Flow,” Ph.D. thesis, Stanford University, Stanford, CA). Wall roughness has a substantial impact on gas phase mean velocities across most of the channel width, except very near the wall. The turbulence intensity of the gas phase is enhanced across the entire channel in the presence of fully rough walls. The rough walls have an even greater impact on the particle phase. Streamwise particle velocities are reduced up to 40%, and become quite uniform across the channel. Particle fluctuating velocities are nearly doubled near the channel centerplane. Profiles appear uniform, due in large part to strong transverse mixing induced by particle-wall collisions. Much of the data of Kulick and Paris is shown here to be strongly influenced by wall conditions with poorly defined roughness in the development region, followed by rapid flow recovery in a relatively smooth test section.
Periodic Velocity Measurements in a Wide and Large Radius Ratio Automotive Torque Converter at the Pump∕Turbine Interface
Authors: Kraus S. O. , Flack R. , Habsieger A. , Gillies G. T. , Dullenkopf K.
Published: May 2005

The unsteady flow field due to blade passing at the pump∕turbine interface of a torque converter was studied. The current geometry is wide and has a large outer to inner radius ratio. A laser velocimeter was used to measure the periodic velocity components at four operating conditions determined by the speed ratios between the turbine and pump of 0.065 (near stall), 0.600, 0.800, and 0.875 (coupling point). The flow fields at the pump exit and turbine inlet planes were visualized and are presented. Using instantaneous pump and turbine blade positions with the velocity data, animations (“slow-motion movies”) are generated to effectively visualize and understand the unsteady behavior. The turbine inlet flow was markedly periodic due to the exiting jet∕wake from the upstream pump passage; however, the pump exit flow field showed little dependence on the turbine blade positions. The highest unsteadiness was seen for the highest speed ratios. Four “shots” from the sequences of one cycle for all speed ratios and each plane are presented herein. The results are also compared to unsteady results for a previously examined torque converter with a small radius ratio to determine the effect of parametric geometric changes on the flow field. Generally, the unsteady velocity fields show no significant difference for the two geometries—the trends are the same.
Improvements in Fixed-Valve Micropump Performance Through Shape Optimization of Valves
Authors: Gamboa Adrian R. , Morris Christopher J. , Forster Fred K.
Published: May 2005

The fixed-geometry valve micropump is a seemingly simple device in which the interaction between mechanical, electrical, and fluidic components produces a maximum output near resonance. This type of pump offers advantages such as scalability, durability, and ease of fabrication in a variety of materials. Our past work focused on the development of a linear dynamic model for pump design based on maximizing resonance, while little has been done to improve valve shape. Here we present a method for optimizing valve shape using two-dimensional computational fluid dynamics in conjunction with an optimization procedure. A Tesla-type valve was optimized using a set of six independent, non-dimensional geometric design variables. The result was a 25% higher ratio of reverse to forward flow resistance (diodicity) averaged over the Reynolds number range 0<Re⩽2000 compared to calculated values for an empirically designed, commonly used Tesla-type valve shape. The optimized shape was realized with no increase in forward flow resistance. A linear dynamic model, modified to include a number of effects that limit pump performance such as cavitation, was used to design pumps based on the new valve. Prototype plastic pumps were fabricated and tested. Steady-flow tests verified the predicted improvement in diodicity. More importantly, the modest increase in diodicity resulted in measured block-load pressure and no-load flow three times higher compared to an identical pump with non-optimized valves. The large performance increase observed demonstrated the importance of valve shape optimization in the overall design process for fixed-valve micropumps.
Slip Factor for Centrifugal Impellers Under Single and Two-Phase Flow Conditions
Authors: Caridad José A. , Kenyery Frank
Published: May 2005

Throughout the history of turbomachines investigators have tried to develop reliable methods for prediction of centrifugal pump behavior. Among the parameters available to estimate the performance of this kind of machine is the slip factor. In spite of being regarded as a variable of great significance in the analysis of turbomachinery, there seem to be a misconception regarding its concept and application. Indeed, empirical correlations have been widely used to estimate the slip factor, even in the case of two-phase flow applications, where it has not been investigated. Moreover, these correlations provide a constant value of the slip factor for a given impeller only at the best efficiency point, which is an important restriction to the pump performance prediction, considering that slip factor varies with the pump flow rate. In this study, three-dimensional computational fluid dynamics simulations were carried out on an impeller of known geometry (NS=1960) from which values of slip factor were calculated for both single- and two-phase flow (water and water-air). These results include curves of the slip factor as a function of the specific capacity and the gas-void fraction. Additionally, results for the slip factor in the case of single-phase flow (water) are given for various centrifugal impellers (NS=1157, 1447, 1612, and 3513) in order to illustrate the influence of the flow rate on this parameter. Finally, based on the numerical results, a methodology for prediction of the pump head is presented. Excellent agreement with experimental results has been found. This paper attempts to contribute to a better understanding of the fluid dynamics within centrifugal pump impellers and to shed more light on the path that prediction models should follow in the future.
The Antimicrobial Activities of Psidium guajava and Juglans regia Leaf Extracts to Acne-Developing Organisms
Authors: Qa'dan Fadi , Thewaini Abdul-Jalil , Ali Dalia A. , Afifi Rana , Elkhawad Abdalla , Matalka Khalid Z.
Published: May 2005

This study aims to present the in vitro inhibitory effect of Psidium guajava and Juglans regia leaf extracts on the main developer of acne lesions, Propionibacterium acnes (P. acnes), and other organisms that are isolated from acne lesions. Thirty-eight subjects (males and females) who had various types of acne were enrolled in the study. The contents of the acne lesions were cultured and the frequency of P. acnes (alone and with Staphylococci spp.) was 47%, whereas the frequencies for Staphylococcus aureus and Staphylococcus epidermidis were 13% and 24%, respectively. The antimicrobial activities of Psidium guajava and Juglans regia leaf extracts, determined by disk diffusion method (zone of inhibition), were compared to tea tree oil (TTO), doxycycline and clindamycin antibiotics. The zones of inhibition due to the Psidium guajava and Juglans regia leaf extracts ranged from 15.8–17.6 mm against P. acnes, 11.3–15.7 mm against S. aureus and 12.9–15.5 mm against S. epidermidis, respectively. These zones of inhibition were significantly higher than those of TTO and equivalent in case of Staphylococci spp., but less in case of P. acnes, to those obtained from doxycycline or clindamycin. It can be concluded that Psidium guajava and Juglans regia leaf extracts may be beneficial in treating acne especially when they are known to have anti-inflammatory activities.
Effect of Eucommia ulmoides on Systolic Blood Pressure in the Spontaneous Hypertensive Rat
Authors: Lang Cynthia , Liu Zhijun , Wayne Taylor H. , Baker David G.
Published: May 2005

Experiments were conducted to establish the safety and efficacy of Eucommia ulmoides (Du-Zhong) extract in the treatment of hypertension. Pilot experiments using rats demonstrated that E. ulmoides extract was safe to the saturation limits of the compound. The maximum tolerated dose (MTD) was 1200 mg/kg when administered by gastric gavage at a concentration of 1200 mg/ml. Also, rats given 200 mg/kg, 600 mg/kg or 1200 mg/kg doses of E. ulmoides extract daily for 28 days demonstrated no evidence of acute toxicity as determined by clinical appearance, histopathology and serum chemistry evaluation. Lastly, spontaneous hypertensive rats (SHRs) were administered E. ulmoides extract daily for 22 days. Systolic blood pressure (BP) was measured on treatment days 1, 8, 15 and 22 at 0, 1, 2 and 3 hours post-treatment. Beginning on day 8, E. ulmoides extract administered at the mid or high dosages lowered BP in male, but not female, rats. BP declined at a rate of approximately 10 mmHg per hour. The mid dosage of 600 mg/kg was found to be the minimum effective dose. In conclusion, E. ulmoides extract was non-toxic and effective in reducing systolic BP in the SHR.
Clinical and Psychological Assessment on Xinwei Decoction for Treating Functional Dyspepsia Accompanied with Depression and Anxiety
Authors: Zhao Lei , Gan Ai-Ping
Published: May 2005

The purpose of this study is to explore the psychological efficacy of Xinwei Decoction, a traditional Chinese herbal medicine, to treat functional dyspepsia (FD) accompanied with depression and anxiety. Seventy-three subjects, divided into three groups, had been given herbal medicine (Xinwei Decoction), prokinetic agent (Domperidone) and placebo, respectively for 8 weeks. Before and after treatment, all subjects were examined with FD symptom scale, Hamilton Depression Scale (HAMD) and Hamilton Anxiety Scale (HAMA). As a result, the total scores of the three groups in FD symptom scale, HAMD and HAMA after treatment decreased in different levels, with the decrease in the herbal group more significant than the other two groups ( p <0.01), indicating the efficacy of the herbal medicine. The total effective rates of the herbal, Domperidone and placebo groups were 90%, 67% and 31%, respectively, which indicated significant effect differences between Xinwei Decoction and Domperidone ( p <0.05) and between Xinwei Decoction and placebo ( p <0.01), showing that the efficacy of herbal therapy was superior to that of the other two therapies. Furthermore, there was no one in the Domperidone and placebo groups being cured of depression and anxiety, while the curing rate in the herbal group was about 70%, indicating the efficacy of herbal medicine in comparison to that of Domperidone and placebo for anti-depression and anti-anxiety. The result demonstrated that Xinwei Decoction could not only alleviate FD symptoms but also relieve depression and anxiety.
Comparing the Effects of Estrogen and an Herbal Medicine on Peripheral Blood Flow in Post-menopausal Women with Hot Flashes: Hormone Replacement Therapy and Gui-Zhi-Fu-Ling-Wan, a Kampo Medicine
Authors: Ushiroyama Takahisa , Ikeda Atsushi , Sakuma Kou , Ueki Minoru
Published: May 2005

We investigated the association between blood flow in the extremities and hot flashes, and compared change in blood flow following hormone replacement therapy (HRT) and Gui-zhi-fu-ling-wan (Keishi-bukuryo-gan), a herbal therapy in post-menopausal women with hot flashes. Three hundred and fifty-two post-menopausal women aged 46–58 years (mean: 53.4±3.6 years) with climacteric complaints participated in the study. One hundred and thirty-one patients with hot flashes were treated with HRT (64 cases) or herbal therapy (67 cases). Blood flow was measured with laser doppler fluxmetry under the jaw, in the middle finger and in the third toe. Post-menopausal women with hot flashes (129 cases) showed significantly higher blood flow under the jaw (13.6±4.13) than women without hot flashes (166 cases) (5.48±0.84) ( p <0.0001). Blood flow at this site decreased significantly with either therapy ( p <0.0001). On the other hand, the administration of Gui-zhi-fu-ling-wan significantly increased ( p =0.002) the blood flow in the lower extremities, whereas HRT decreased the blood flow.

Thus, we have demonstrated that Gui-zhi-fu-ling-wan did not affect the activity of vasodilator neuropeptides on sensory neurons of systemic peripheral vessels uniformly. Therefore, Gui-zhi-fu-ling-wan, rather than HRT, is suggested as an appropriate therapy for treatment of hot flashes in the face and upper body with concomitant coldness in the lower body, which is one of the symptoms of menopause.
Protective Effect of Hawthorn Fruit on Murine Experimental Colitis
Authors: Fujisawa Min , Oguchi Katsuji , Yamaura Taku , Suzuki Megumi , Cyong Jong-Chol
Published: May 2005

The pathogenic mechanism and effective treatment of inflammatory bowel disease (IBD) are still unknown. In the present study, we examined the protective effect of hawthorn fruit (Crataegi fructus) on two murine colitis models: dextran sulfate sodium (DSS) and 2,4,6-trinitrobenzene sulfonic acid (TNBS) colitis. Mice that developed acute colitis showed signs of diarrhea, gross rectal bleeding and weight loss within 10 days. However, hawthorn fruit (2 g/kg body weight) restored the body weight and colon length and increased hemoglobin count in these animals. Hawthorn fruit not only decreased signs of inflammation such as infiltration by polymorphonuclear leukocytes and multiple erosive lesions, but also showed improvement of leukotriene B4 (LTB4), a biochemical parameter of inflammation mass. TNBS colitis mice had significantly lower rates of survival than normal control animals; however, treatment with hawthorn fruit significantly improved survival in TNBS colitis mice. The results suggest that hawthorn fruit and the Kampo formula that contains this ingredient may have potential therapeutic utility in patients with IBD.
Protective Effect of Jakyak-Gamcho-Tang Extract and Its Constituents Against t-BHP-Induced Oxidative Damage in HT22 Cells
Authors: Kang Tai-Hyun , Baek Hum-Young , Kim Youn-Chul
Published: May 2005

The present study investigated whether Jakyak-Gamcho-Tang (JGT, Shaoyao-Gancao-tang) and its constituents have the protective effect against tert-butyl hydroperoxide (t-BHP)-induced cytotoxicity on hippocampal HT22 cell line. JGT consists of two medicinal herbs, Paeoniae Radix (PR) and Glycyrrhizae Radix (GR). In contrast to treating with t-BHP alone, pre-treatment of HT22 cells with JGT, PR and GR (50–400 μg/ml) for 3 hours significantly increased the cell viability in a concentration-dependent manner. In addition, JGT, PR and GR exhibited the scavenging activity in both 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and superoxide anion assays. Among the tested extracts, PR showed the most potent protective and antioxidative activities. These results suggest that PR acts as an antioxidant and this property may contribute to the neuroprotective activity of JGT extract.
Susceptibilities of Mycoplasma hominis to Herbs
Authors: Che Ya-Min , Mao Shu-He , Jiao Wen-Ling , Fu Zhi-Yi
Published: May 2005

To determine the susceptibilities of Mycoplasma homonis (M. hominis) to Chinese medicinal herbs in vitro, 30 clinical strains of M. hominis were isolated and identified from the clinical specimen. The susceptibilities of M. hominis to 19 herbs were determined by serial dilution methods in vitro. The results showed that M. hominis was susceptible to Radix Isatidis, Radix Angelicae Dahuricae, Cortex Phellodendri, Radix et Rhizoma Rhei, Fructus Kochiae and Herba Houttuyniae. These findings laid a foundation in treating M. hominis infection with Chinese herbs.
The Anti-depressant Effect of Nelumbinis Semen on Rats Under Chronic Mild Stress Induced Depression-like Symptoms
Authors: Kang Moonkyu , Shin Dongwon , Oh Jung-Wan , Cho Chongwoon , Lee Hwa-Jin , Yoon Dong-Won , Lee Sang-Moon , Yun Jung-Hwan , Choi Hyun , Park Seongkyu , Shin Minkyu , Hong Moochang , Bae Hyunsu
Published: May 2005

Nelumbinis Semen is a well-known traditional herbal medicine frequently used in treatment of depression in many Asian countries. In this study, its anti-depression effects in rats were investigated by comparing the test results of those treated with Nelumbinis Semen to those treated with other herbal anti-depressants, including Rehmanniae Radix Preparat, Corni Fructus, Lycii Fructus, Pinelliae Rhizoma and Hypericum Perforatum.

In order to induce depression-like symptoms, the animals were placed under chronic mild stress in the form of overnight illumination for 2 consecutive days. They were treated with the respective herbal extract and forced swimming tests were conducted afterwards. The anti-depression effects of each extract were then evaluated based on a measured index, which consisted of struggling time, first latency and first rest duration.

These test results show that Nelumbinis Semen provides greater anti-depression effects than the other herbal extracts. Specifically, only the rats treated with Nelumbinis Semen showed significant increases in struggling time (43.9%, p <0.005, p =0.0037) and in first latency time (90.2%, p <0.05, p =0.0116). However, the first rest duration for Nelumbinis Semen treated rats was not significantly different from the other rats. It appears that Nelumbinis Semen provides even greater anti-depression effects than Hypericum Perforatum (commonly referred to as St. John's Wort, perhaps the most widely used natural anti-depressant today). The anti-depression effects of Nelumbinis Semen might be due to the modulation of the amount of neurotransmitters involved in depression.
Immune Activation and Radioprotection byPropolis
Authors: Takagi Yasuyuki , Choi In-Sook , Yamashita Takenori , Nakamura Takashi , Suzuki Ikukatsu , Hasegawa Takeo , Oshima Masami , Gu Yeun-Hwa
Published: May 2005

In this study, we focused on immune stimulation by Propolis, and examined changes in the effect of irradiation after Propolis administration. We also examined the radioprotective effect of Propolis by observing its effect on the immune system. The effect of immune activation by Propolis was investigated by measuring the total immunoglobulin (Ig) G and IgM. The radioprotective effect of immune activation by Propolis was investigated by measuring the T-lymphocyte subsets in the peripheral blood of mice following whole body irradiation.

Compared with the control group, the IgG was significantly reduced in the Propolis group, indicating that Propolis suppressed IgG production. ELISA revealed that the amount of IgM in mouse serum was significantly higher in the Propolis group as compared with the control group, indicating that Propolis increased IgM production.

The number of CD4-positive cells was increased only in the Propolis group. Likewise, the number of CD4-positive cells increased by 81% in the Propolis with irradiation group compared with the irradiation group alone. Compared with the control group, the Propolis group increased CD8-positive cells. Compared with the irradiation alone group, CD8-positive cells were decreased by Propolis with irradiation group.

Propolis activated macrophages to stimulate interferon (IFN)-γ production in association with the secondary activation of T-lymphocytes, resulting in a decrease in IgG and IgM production. Cytokines released from macrophages in mouse peripheral blood after Propolis administration activated helper T-cells to proliferate. In addition, activated macrophages in association with the secondary T-lymphocyte activation increased IFN-γ production and stimulated proliferation of cytotoxic T-cells and suppressor T-cells, indicating the activation of cell-mediated immune responses.
Efficacy and Safety of Chunghyul-dan (Qingwie-dan) in Patients with Hypercholesterolemia
Authors: Cho Ki Ho , Kang Heung Sun , Jung Woo Sang , Park Seong Uk , Moon Sang Kwan
Published: May 2005

Chunghyul-dan has inhibitory effects on HMG- CoA reductase and pancreatic lipase. We investigated whether Chunghyul-dan has therapeutic effects on humans with hypercholesterolemia. This study was a case-control, open-labeled clinical study. Subjects were treated with Chunghyul-dan (600 mg/day) or Atorvastatin (10 mg/day) for 8 weeks. Serum lipids were checked at baseline after 4 and 8 weeks of medication. While, Chunghyul-dan showed significant lipid-lowering effects, it was less effective than Atorvastatin. In comparison with the histological controls, Chunghyul-dan's effects were superior to placebo. On safety assessment, there was no adverse effect with the use of Chunghyul-dan in hepatic or renal toxicity. In conclusion, we suggest that Chunghyul-dan is a useful herbal medicine for hypercholesterolemia.
The Use of Preventive Strategies for Bone Loss
Authors: Xu Hong , Lawson David , Kras Annette , Ryan Damien
Published: May 2005

Osteoporosis is a worldwide problem that is increasing significantly as the global population both increases and ages. While osteoporosis has been extensively studied in recent years, the utilization of traditional Chinese medicine (TCM) for the diagnosis, prevention and treatment of this condition has seldom been examined. This paper examines the theories and the literature that relate to diagnosis, prevention and treatment of bone loss at the time of menopause according to the principles of TCM. It also considers practical developments in these areas as illustrated by the authors' research findings in recent studies. TCM diagnosis attributes a number of different underlying patterns to menopausal bone loss. A very common pattern in this situation is a Kidney qi and yin deficiency pattern. TCM analysis can be used as an early determinant of those persons who are potentially at risk of bone loss. Acupuncture, herbal medicine and Tai Ji exercise can then be applied to prevent and treat osteoporosis. These treatments can be effective, if they are applied correctly. The therapies may also be used in the treatment and prevention of osteoporosis, as well as the general maintenance of women's health during menopause.
Atropine-Induced HRV Alteration is Not Amended by Electroacupuncture on Zusanli
Authors: Chang Chi-Hsien , Huang Jin-Long , Ting Chih-Tai , Chang Chi-Sen , Chen Gran-Hum
Published: May 2005

Acupuncture is known to influence autonomic nervous activity. Acupuncture on Zusanli points has been shown to enhance the regularity of gastric myoelectrical activity and accelerate gastric emptying, partly through the vagal pathway, in dogs. The aim of this study was to evaluate whether atropine-induced autonomic nervous alteration, measured by heart rate variability (HRV), could be amended by electroacupuncture on Zusanli points. HRV measurements were recorded in 15 healthy volunteers before, during and after electroacupuncture. Each subject was studied for three sessions in a randomized sequence, which included electroacupuncture on the Zusanli (St 36) points with or without premedication of atropine and placebo stimulation on a non-acupoint. The analysis of low frequency (LF), high frequency (HF) and LF/HF ratios were compared between different sessions. Serum levels of gastrin, motilin and pancreatic polypeptide (PP) levels were also measured. There was an increase in the LF/HF ratio (indicating increased sympathetic activity) during the post-acupuncture period with 2 Hz of electrical stimulation on the Zusanli acupoints. When IV atropine was used immediately before the electroacupuncture, there was a decrease in the LF power and HF power during the acupuncture and post-acupuncture periods. In addition, there was a significant increase in the LF/HF ratio during the acupuncture and post-acupuncture periods. There was a significant decrease in serum PP in the post-acupuncture period after premedication with IV atropine. In conclusion, atropine-induced HRV change might be mediated via the vagal pathway. However, atropine-induced HRV alteration is not amended by electroacupuncture on Zusanli points.
Deqi Sensation Between the Acupuncture-Experienced and the Naïve: A Korean Study II
Authors: Park Jongbae , Park Hijoon , Lee Hyangsook , Lim Sabina , Ahn Kyooseok , Lee Hyejung
Published: May 2005

Previous experience of acupuncture is believed to affect people's expectation of future treatments. Therefore, subjects who have had acupuncture are generally excluded from sham-controlled acupuncture clinical trials. However, this assumption has not been proven, but just accepted because of the lack of evidence to the contrary. To investigate the difference in frequency and intensity of acupuncture sensation between subjects who have had acupuncture and those who have not, 36 acupuncture-experienced subjects were invited to take part in the study. After informed consent was obtained, participants were asked to complete the acupuncture sensation scale (ASS) according to what they expected needling to feel like. The needling was done at the left Hegu (LI 4) point and consisted of insertion, stimulation for 30 seconds and removal. After needling, the subjects were asked to complete the same ASS according to what they actually experienced. Adverse events were monitored. The frequency of each sensation expected and experienced, as well as acupuncture sensation scores were compared. More than 60% of the subjects expected to feel sensations of penetrating (87.6% to 100%), aching (71.2% to 95.5%), tingling (87.6% to 100%), pricking (79.7% to 99.2%) and throbbing (64.2% to 91.4%). In fact, the subjects experienced sharp (60.9% to 89.1%), intense (60.9% to 89.1%), radiating (71.2% to 95.5%) and heavy (74.8% to 97.4%) sensations just as much. The subjects expected more hurting ( p =0.001), tingling ( p <0.001), pricking ( p =0.010), stinging ( p =0.012), burning ( p =0.001) and pulsing ( p =0.009) than they experienced, while more heaviness ( p =0.011) was experienced than expected. The same outcome measures were also compared between experienced and naïve groups. Apart from the fact that the acupuncture-experienced participants expected to feel pricking ( p =0.030) and stinging ( p =0.002), and experienced hurting ( p =0.022) and stinging ( p =0.028) significantly less than those who had not had acupuncture before, there was no significant difference between first time and experienced subjects. The results indicate that previous experience does not affect the people's expectation and does not hinder people from experiencing Deqi. In addition, a constellation of Deqi-related acupuncture-specific sensations is more than just a general pain intensity dimension, which requires a biochemical and physiological exploration.
How Galen's "Sixteen Books" Came to China in the Tenth Century AD
Authors: Klein-Franke Felix , Ming Zhu
Published: May 2005

Ibn an-Nadīm, the famous 10th century bookseller and bibliographer of Baghdad and author of the "Fihrist" (Catalogue), tells the story of an unnamed Chinese student who found in the library of the famous physician and philosopher ar-Rāzī the so-called "Sixteen Books," i.e. the Arabic summary of the most influential books written by Galen, and translated them into Chinese. We do not know if this Chinese translation was safely transported to China.
A NEIGHBORHOOD SELECTION METHOD FOR CELLULAR AUTOMATA MODELS
Authors: MEI S. S. , BILLINGS S. A. , GUO L. Z.
Published: May 2005

A new neighborhood selection method is presented for both deterministic and probabilistic cellular automata models. The detection criteria are built explicitly on the corresponding contribution which is made to the value of each updated cell from each detected cell in the evolution. Theoretical analysis and numerical simulations demonstrate the effectiveness of this new method.
FLOWER PATTERNS APPEARING ON A HONEYCOMB STRUCTURE AND THEIR BIFURCATION MECHANISM
Authors: SAIKI ISAO , IKEDA KIYOHIRO , MUROTA KAZUO
Published: May 2005

Illuminative deformation patterns of a honeycomb structure are presented. A representative volume element of a honeycomb structure consisting of 2 × 2 hexagonal cells is modeled to be a [Formula: see text]-equivariant system. The bifurcation mechanism and an exhaustive list of possible bifurcated patterns are obtained by group-theoretic bifurcation theory. A flower mode of the honeycomb is shown to have the same symmetry as the so-called anti-hexagon in the Rayleigh–Bénard convection. A numerical bifurcation analysis is conducted on an elastic in-plane honeycomb structure consisting of 2×2 cells to produce beautiful wallpapers of bifurcating deformation patterns and, in turn, to highlight the achievement of the paper. New deformation patterns of a honeycomb structure have been found and classified in a systematic manner. Knowledge of the symmetries of the bifurcating solutions has turned out to be vital in the successful numerical tracing of the bifurcated paths. This paper paves the way for the introduction of the results hitherto obtained for flow patterns in fluid dynamics into the study of patterns on materials.
EVALUATION OF A NONLINEAR BISTABLE FILTER FOR BINARY SIGNAL DETECTION
Authors: ROUSSEAU DAVID , VARELA JULIO ROJAS , DUAN FABING , CHAPEAU-BLONDEAU FRANÇOIS
Published: May 2005

We consider the nonlinear bistable dynamic system that is the archetypal system giving way to the phenomenon of stochastic resonance for noise-improved signal processing. Independently of a strict stochastic resonance effect, we use this bistable system as a nonlinear filter for a detection task on a binary signal. We expose a methodology to tune the nonlinear filter at its best performance that minimizes its probability of detection error. The optimally tuned nonlinear filter is then compared to the ideal matched filter, which is the optimal filter for the detection with Gaussian noise. We show that the performance of the nonlinear filter, although (expectedly) not as good, comes close to that of the ideal matched filter operating in its strict nominal conditions. We next examine several possible departures, quite plausible in practical operation, from the nominal conditions of the ideal matched filter. We demonstrate that in such degraded conditions, the nonlinear filter can catch up and surpass the performance of the matched filter. This reveals a robustness superiority of the nonlinear filter, compared to the matched filter operating outside its strict nominal conditions.
CONVERGENCE OF DISCRETE-TIME RECURRENT NEURAL NETWORKS WITH VARIABLE DELAY
Authors: LIANG JINLING , CAO JINDE , LAM JAMES
Published: May 2005

In this paper, some global exponential stability criteria for the equilibrium point of discrete-time recurrent neural networks with variable delay are presented by using the linear matrix inequality (LMI) approach. The neural networks considered are assumed to have asymmetric weighting matrices throughout this paper. On the other hand, by applying matrix decomposition, the model is embedded into a cooperative one, the latter possesses important order-preserving properties which are basic to our analysis. A sufficient condition is obtained ensuring the componentwise exponential stability of the system with specific performances such as decay rate and trajectory bounds.
CRYPTANALYSIS OF OBSERVER BASED DISCRETE-TIME CHAOTIC ENCRYPTION SCHEMES
Authors: SOLAK ERCAN
Published: May 2005

This paper investigates the weaknesses of cryptosystems that use observer based synchronized chaotic systems. It is shown that known plaintext and chosen plaintext attacks can successfully be launched against such cryptosystems to recover the system parameters and subsequently eavesdrop on the message transmission. The methods employed rely only on the basic mathematical relations that exist between the output sequence and the message sequence of the transmitter system and require very less computations.
EXCLUSION OF FALSE PERIODIC ORBITS DETECTED FROM CHAOTIC TIME SERIES
Authors: YAGASAKI KAZUYUKI , KOUYAMA MASATOSHI
Published: May 2005

Some techniques based on delay coordinates embedding for detecting unstable periodic orbits from chaotic time series work successfully in several applications but frequently yield false periodic orbits. We present a simple method for excluding false ones from candidates of periodic orbits obtained from chaotic time series. We demonstrate our method in numerical simulations for the Ikeda map and experiments for periodically forced, single and coupled pendula.
AN EXTENSION OF A METHOD OF YAGASAKI AND UOZUMI
Authors: HILL D. L.
Published: May 2005

A method for controlling onto saddle-type fixed points developed by Yagasaki and Uozumi is extended so as to make the capture region many times larger than that of the original method.
ESTIMATION OF AN ATTRACTION REGION IN ONE-DIMENSIONAL DELAYED-FEEDBACK CONTROL SYSTEMS
Authors: KONISHI KEIJI
Published: May 2005

This paper presents a simple numerical scheme for estimating the attraction region of a fixed point in one-dimensional discrete-time chaotic systems controlled by the delayed-feedback method. This scheme employs the well-known linear matrix inequality approach. A systematic procedure for estimating the region is provided, and numerical examples are used to validate the results.
BIFURCATIONS IN GLASS NETWORKS
Authors: KILLOUGH D. B. , EDWARDS R.
Published: May 2005

Glass networks have been proposed as a model framework for gene regulation, chemical kinetics and neural networks. Their main distinguishing feature is that although the network variables evolve continuously in time, interactions between them depend discontinuously on their sign (i.e. above or below a threshold). While this is a simplification, it has tremendous analytic advantages if the approximation is reasonable in an application. This study explores and classifies bifurcations in Glass networks, and relates them to bifurcations of smooth systems. These bifurcations can often not be studied with traditional bifurcation theory, as the vector fields are discontinuous. However, the theory that has been developed for periodic orbits of Glass networks allows a natural classification for bifurcations of periodic orbits. Some of these are shown to correspond to smooth-system bifurcations, others are shown to fit into the framework of "C-bifurcations" or "border-collision bifurcations" and others are shown to allow truly ambiguous behavior, for which Filippov's theory for discontinuous vector fields is an appropriate tool. Routes to chaos are also explored, and it is demonstrated that period-doubling cascades do not occur. However, sudden transitions to chaos, which are common in Glass networks, can result in a limiting sense from compression to a point of a period-doubling cascade in corresponding networks with sigmoidal interactions as the sigmoid's gain is increased. Other phenomena such as intermittency and multistability are also discussed.
BIFURCATION ANALYSIS OF A DELAYED DYNAMIC SYSTEM VIA METHOD OF MULTIPLE SCALES AND SHOOTING TECHNIQUE
Authors: WANG HUAILEI , HU HAIYAN
Published: May 2005

This paper presents a detailed study on the bifurcation of a controlled Duffing oscillator with a time delay involved in the feedback loop. The first objective is to determine the bifurcating periodic motions and to obtain the global diagrams of local bifurcations of periodic motions with respect to time delay. In order to determine the bifurcation point, an analysis on the stability switches of the trivial equilibrium is first performed for all possible parametric combinations. Then, by means of the method of multiple scales, an analysis on the local bifurcation of periodic motions is given. The static bifurcation diagrams on the amplitude-delay plane exhibit two kinds of local bifurcations of periodic motions, namely the saddle-node bifurcation and the pitchfork bifurcation, indicating a sudden emergence of two periodic motions with different stability and a Hopf bifurcation, respectively, in the sense of dynamic bifurcation. The second objective is to develop a shooting technique to locate both stable and unstable periodic motions of autonomous delay differential equations such that the periodic motions and their stability predicted using the method of multiple scales could be verified. The efficacy of the shooting scheme is well illustrated by some examples via phase trajectory and time history. It is shown that periodic motions located by the shooting method agree very well with those predicted on the bifurcation diagrams. Finally, the paper presents some interesting features of this simple, but dynamics-rich system.
DYNAMIC COMPLEXITIES IN A LOTKA–VOLTERRA PREDATOR–PREY MODEL CONCERNING IMPULSIVE CONTROL STRATEGY
Authors: LIU BING , ZHANG YUJUAN , CHEN LANSUN
Published: May 2005

Based on the classical Lotka–Volterra predator–prey system, an impulsive differential equation to model the process of periodically releasing natural enemies and spraying pesticides at different fixed times for pest control is proposed and investigated. It is proved that there exists a globally asymptotically stable pest-eradication periodic solution when the impulsive period is less than some critical value. Otherwise, the system can be permanent. We observe that our impulsive control strategy is more effective than the classical one if we take chemical control efficiently. Numerical results show that the system we considered has more complex dynamics including period-doubling bifurcation, symmetry-breaking bifurcation, period-halving bifurcation, quasi-periodic oscillation, chaos and nonunique dynamics, meaning that several attractors coexist. Finally, a pest–predator stage-structured model for the pest concerning this kind of impulsive control strategy is proposed, and we also show that there exists a globally asymptotically stable pest-eradication periodic solution when the impulsive period is less than some threshold.
CONTROLLING CHAOS TO A CLASS OF PDEs BY APPLYING INVARIANT MANIFOLD AND STRUCTURE STABILITY THEORY
Authors: ZHAO YI , HOU S. H.
Published: May 2005

In this paper, we are concerned with the chaotic behavior of a class of control systems described by partial differential equations. By means of finite dimensional output feedback control, it is shown that the flow on the global attractor is topologically equivalent to that of a finite dimensional difference system. In addition, an example is given to illustrate that the chaotic behavior of the flow on the global attractor can be determined by computing the Lyapunov exponent of an associated finite dimensional difference system.
A FAST AND STABLE NUMERICAL SOLUTION FOR ACOUSTIC BOUNDARY ELEMENT METHOD EQUATIONS COMBINED WITH THE BURTON AND MILLER METHOD FOR MODELS CONSISTING OF CONSTANT ELEMENTS
Authors: OSETROV ALEXANDER V. , OCHMANN MARTIN
Published: May 2005

Theory and algorithm for the acoustic boundary element solver will be described. The solver represents the core of the package AField (acronym for acoustical field) and can be used for getting fast and stable solutions for huge as well as for small boundary elements models on PCs under Windows. The boundary element solver includes an early proposed GMRES iterative linear system solver (which can be used for big and huge models) and several traditional linear system solvers (for small and medium models). Implementation of the Burthon and Miller regularization method for constant boundary elements will be discussed. Approximations in proposed boundary element solver and their influence on solution errors are investigated. Results for several models are included. Several possibilities of Afield package are illustrated.
NUMERICAL PREDICTIONS OF SOUND PROPAGATION FROM A CUTTING OVER A ROAD-SIDE NOISE BARRIER
Authors: PEPLOW ANDREW T.
Published: May 2005

A boundary integral equation is described for the prediction of acoustic propagation from a monofrequency coherent line source in a cutting with impedance boundary conditions onto surrounding flat impedance ground. The problem is stated as a boundary value problem for the Helmholtz equation and is subsequently reformulated as a system of boundary integral equations via Green's theorem. The numerical solution of the coupled boundary integral equations by a simple boundary element method is then described. Predictions of A-weighted insertion losses for a traffic noise spectrum are made illustrating the effects of depth of the cutting and the profile of the associated noise barrier.
AN EFFECTIVE SETTING OF HIERARCHICAL CELL STRUCTURE FOR THE FAST MULTIPOLE BOUNDARY ELEMENT METHOD
Authors: YASUDA Y. , SAKUMA T.
Published: May 2005

The fast multipole boundary element method (FMBEM) is an advanced BEM that leads to drastic reduction of processing time and memory requirements in a large-scale steady-state sound field analysis. In the FMBEM, hierarchical cell structure is employed to apply multipole expansion in multiple levels, and the setting of the hierarchical cell structure considerably affects the computational efficiency of the FMBEM. This paper deals with effective settings of hierarchical cell structure for taking full advantage of the FMBEM. A numerical study with objects of different shapes with the same DOF shows that both the computational complexity and the memory requirements with the FMBEM were greater for 1D-shaped objects than for 2D- or 3D-shaped ones, without a special setting of hierarchical cell structure for each problem. An effective setting for 1D-shaped objects is derived through theoretical and numerical studies, where special considerations are given to the arrangement of the cell structure and the treatment of translation coefficients between cells. This setting allows for efficient calculations not dependent on the shape of an analyzed object. A simple method to arrange hierarchical cell structure is proposed, which realizes the derived setting for arbitrarily-shaped problems.
IMPROVEMENT OF A HIGH-FREQUENCY BROADBAND ENERGY-INTENSITY BOUNDARY ELEMENT METHOD TO INCLUDE HIGH RESOLUTION SPECULAR REFLECTION
Authors: ROUSE JERRY , FRANZONI LINDA
Published: May 2005

The prediction of the spatial mean-square pressure distribution within enclosed high-frequency broadband sound fields is computationally intensive if determined on a frequency-by-frequency basis. Recently an energy-intensity boundary element method (EIBEM) has been formally developed. This method employs uncorrelated broadband directional energy sources to expeditiously predict such pressure distributions. The source directivity accounts for local correlation effects and specular reflection. The method is applicable to high modal density fields, but not restricted to the usual low-absorption, diffuse, and quasi-uniform assumptions. The approach can accommodate fully specular reflection, or any combination of diffuse and specular reflection. This boundary element method differs from the classical version in that element size is large compared to an acoustic wavelength and equations are not solved on a frequency-by-frequency basis. In the earlier EIBEM, the source strength and directivity associated with the energy sources, distributed over enclosure boundaries, were determined in an iterative manner and the directivity was limited to three terms of a Fourier expansion. Here, the original method is improved by eliminating the iteration and allowing for an unlimited number of terms in the Fourier expansion of the directivity function. For verification, the improved EIBEM is compared to experimental measurements and exact analytical solutions; excellent agreement is obtained.
CAT'S EYE RADIATION WITH BOUNDARY ELEMENTS: COMPARATIVE STUDY ON TREATMENT OF IRREGULAR FREQUENCIES
Authors: MARBURG STEFFEN , AMINI SIA
Published: May 2005

This paper reviews a number of techniques developed to overcome the well-known nonuniqueness problem in boundary integral formulations of acoustic radiation. Although the problem has received much attention, comparative studies are hardly known in this field. Furthermore, the problem has often been studied using an unsuitable example, namely a simple radiating sphere. In this case, often the addition of one collocation point in the centre of the sphere suffices to remove the nonuniqueness problem for a large range of wavenumbers. In contrast to the radiating sphere, the radiating cat's eye structure is considered in this paper. Solution of the discretized ordinary Kirchhoff–Helmholtz integral equation, also known as the Surface Helmholtz Equation, reveals a large number of so-called irregular frequencies, i.e. frequencies where the BEM fails. The paper compares the performance of different methods in alleviating this failure. The CHIEF method and its variation due to Rosen et al. are found to encounter difficulties at high frequencies. A much better performance is obtained by combining the Kirchhoff–Helmholtz integral equation with its normal derivative. In particular the method of Burton and Miller and a modification of it which avoids evaluating the hypersingular operator at nonsmooth points are tested. Both methods seem to provide reliable solutions. The modified method encounters minor failures in the frequency response function at a geometric singularity, although performing surprisingly well in many cases. More tests need to be carried out to assess fully the effectiveness of this method which allows easy use of continuous quadratic elements. However, it is the Burton and Miller formulation which appears to be the most reliable for acoustic radiation analysis. The use of CHIEF and its variations cannot be recommended.
APPLICATION OF THE FAST MULTIPOLE BEM FOR STRUCTURAL–ACOUSTIC SIMULATIONS
Authors: FISCHER MATTHIAS , GAUL LOTHAR
Published: May 2005

The fast multipole method is employed to accelerate the Galerkin boundary element method for acoustics. Important parameters as the nearfield size and the expansion length are discussed and numerical examples are provided. An approximate inverse preconditioner and a preconditioner based on spectral properties of the boundary integral operators are presented. For the example of sound radiation from a brake disk, both approaches prove suitable to reduce the iteration count and to improve the efficiency of the method.
ACOUSTIC DESIGN SENSITIVITY ANALYSIS FOR INTERIOR SPACES USING THE MULTI-DOMAIN BEM
Authors: JEONG JI-HOON , IH JEONG-GUON , LEE BYUNG-CHAI
Published: May 2005

In applying the boundary element method to an acoustic interior problem modeled as a single domain, even a small change of the cavity geometry affects the whole system matrix. Thus, calculating sensitivities for each intermediate shape is performed independently during iterations for an optimum shape. By utilizing the sub-domain modularization capability of the MBEM, however, the matrix inversion task is performed only once for the initial shape during whole iterations. This can reduce the total computational costs of finding an optimum shape design and the computational efficiency increases as the number of iterations increases. A demonstration example is given by a two-dimensional automotive interior cavity.