Showing papers by "Ford Motor Company published in 2003"

Intravenous administration of human bone marrow stromal cells induces angiogenesis in the ischemic boundary zone after stroke in rats.

Abstract: We tested the hypothesis that intravenous infusion of human bone marrow stromal cells (hMSCs) promotes vascular endothelial growth factor (VEGF) secretion, VEGF receptor 2 (VEGFR2) expression and angiogenesis in the ischemic boundary zone (IBZ) after stroke. hMSCs (1×106) were intravenously injected into rats 24 hours after middle cerebral artery occlusion (MCAo). Laser scanning confocal microscopy (LSCM), immunohistochemistry and ELISA were performed to assay angiogenesis and levels of human and rat VEGF in the host brain, respectively. In addition, capillary-like tube formation was measured using mouse brain-derived endothelial cells (MBDECs). Morphological and three dimensional image analyses revealed significant ( P <0.05) increases in numbers of enlarged and thin walled blood vessels and numbers of newly formed capillaries at the boundary of the ischemic lesion in rats (n=12) treated with hMSCs compared with numbers in rats (n=12) treated with PBS. ELISA measurements showed that treatment with hMSCs significantly ( P <0.05) raised endogenous rat VEGF levels in the IBZ from 10.5±1.7 ng/mL in the control group to 17.5±1.6 ng/mL in the hMSC-treated group. In addition, treatment with hMSCs increased endogenous VEGFR2 immunoreactivity. In vitro, when MBDECs were incubated with the supernatant obtained from cultured hMSCs, capillary-like tube formation was significantly ( P <0.01) induced. However, hMSC-induced capillary-like tube formation was significantly ( P <0.01) inhibited when the endothelial cells were incubated with the supernatant from hMSCs in the presence of a neutralizing anti-VEGFR2. These data suggest that treatment of stroke with hMSCs enhances angiogenesis in the host brain and hMSC-enhanced angiogenesis is mediated by increases in levels of endogenous rat VEGF and VEGFR2.

Search query processing to provide category-ranked presentation of search results

Abstract: A search engine system displays the results of a multiple-category search according to levels of relevance of the categories to a user's search query. A query server receives a search query from a user and identifies, within each of multiple item categories, a set of items that satisfy the query. The sets of items are used to generate, for each of the multiple categories, a score that reflects a level significance or relevance of the category to the search. The scores may be based, for example, on the number of hits within each category relative to the total number of items in that category, the popularity levels of items that satisfy the query, a personal profile of the user, or a combination thereof. The categories are then presented to the user, together with the most relevant items within each category, in the order of highest to lowest category relevance.

Intravenous bone marrow stromal cell therapy reduces apoptosis and promotes endogenous cell proliferation after stroke in female rat

Abstract: The present study investigates the induction of neurogenesis, reduction of apoptosis, and promotion of basic fibroblast growth factor (bFGF) expression as possible mechanisms by which treatment of stroke with bone marrow stromal cells (MSCs) improves neurological functional recovery. Additionally, for the first time, we treated cerebral ischemia in female rats with intraveneous administration of MSCs. Female rats were subjected to 2 hr of middle cerebral artery occlusion (MCAo), followed by an injection of 3 x 10(6) male (for Y chromosome labeling) rat MSCs or phosphate-buffered saline (PBS) into the tail vein 24 hr after MCAo. All animals received daily injection of bromodeoxyuridine (BrdU; 50 mg/kg, i.p.) for 13 days after treatment for identification of newly synthesized DNA. Animals were sacrificed at 14 days after MCAo. Behavioral tests (rotarod and adhesive-removal tests) were performed. In situ hybridization, immunohistochemistry, and terminal deoxynucleotidyltransferase (TdT)-mediated dUTP-biotin nick-end labeling (TUNEL) were performed to identify transplanted MSCs (Y chromosome), BrdU, bFGF, and apoptotic cells in the brain. Significant recovery of behavior was found in MSC-treated rats at 7 days in the somatosensory test and at 14 days in the motor test after MCAo compared with control, PBS-treated animals (P<.05). MSCs were found to survive and preferentially localize to the ipsilateral ischemic hemisphere. Significantly more BrdU-positive cells were located in the subventricular zone (P<.05), and significantly fewer apoptotic cells and more bFGF immunoreactive cell were found in the ischemic boundary area (P<.05) of MSC-treated rats than in PBS-treated animals. Here we demonstrate that intravenously administered male MSCs increase bFGF expression, reduce apoptosis, promote endogenous cellular proliferation, and improve functional recovery after stroke in female rats.

Statins induce angiogenesis, neurogenesis, and synaptogenesis after stroke

Abstract: We demonstrate that the 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase inhibitors atorvastatin and simvastatin enhance functional outcome and induce brain plasticity when administered after stroke to rats. With atorvastatin treatment initiated 1 day after stroke, animals exhibited significant increases in vascular endothelial growth factor, cyclic guanosine monophosphate, angiogenesis, endogenous cell proliferation and neurogenesis, and an increase in the synaptic protein, synaptophysin. Atorvastatin-induced angiogenesis in a tube formation assay was reduced by an antibody against the vascular endothelial growth factor receptor 2 (FIK-1) and by the nitric oxide synthase inhibitor, N-mono-methyl-L-arginine (L-NAME). Atorvastatin also induced phosphorylation of Akt and Erk in cultured primary cortical neurons. These data indicate that atorvastatin induced brain plasticity and has neurorestorative activity after experimental stroke.

Product modularity: Definitions and benefits

Abstract: The present paper presents an overview of existing research on the definition of modular product design and its benefits. Modularity has been discussed in terms of product development for quite some time. In recent years, the discussions have increased. The development of metrics and methods has also increased. However, these metrics and methods are often based on different definitions and varying goals. Understanding what modularity is and why it is useful is the foundation of modular product design. The purpose of this paper is to examine the existing literature and draw conclusions about where consensus exists and areas for further discussion. The relationship to product platform planning is also shown. This overview shows that there is a clear consensus on the point of independence of form and function. Within this definition, there is a strong pressure to extend modularity beyond form-function concerns and out across the life-cycle. Additionally, there is pressure to look at similarity or compatibili...

Sustained efficacy of eszopiclone over 6 months of nightly treatment: results of a randomized, double-blind, placebo-controlled study in adults with chronic insomnia.

Abstract: STUDY OBJECTIVES To determine the long-term efficacy of eszopiclone in patients with chronic insomnia. DESIGN Randomized, double-blind, multicenter, placebo-controlled. SETTING Out-patient, with monthly visits. PATIENTS Aged 21 to 69 years meeting DSM IV criteria for primary insomnia and reporting less than 6.5 hours of sleep per night, and/or a sleep latency of more than 30 minutes each night for at least 1 month before screening. INTERVENTIONS Eszopiclone 3 mg (n = 593) or placebo (n = 195), nightly for 6 months MEASUREMENTS AND RESULTS Efficacy was evaluated weekly using an interactive voice-response system. Endpoints included sleep latency; total sleep time; number of awakenings; wake time after sleep onset; quality of sleep; and next-day ratings of ability to function, daytime alertness, and sense of physical well-being. At the first week and each month for the study duration, eszopiclone produced significant and sustained improvements in sleep latency, wake time after sleep onset, number of awakenings, number of nights awakened per week, total sleep time, and quality of sleep compared with placebo (P < or = 0.003). Monthly ratings of next-day function, alertness, and sense of physical well-being were also significantly better with the use of eszopiclone than with placebo (P < or = 0.002). There was no evidence of tolerance, and the most common adverse events were unpleasant taste and headache. CONCLUSIONS Throughout 6 months, eszopiclone improved all of the components of insomnia as defined by DSM-IV, including patient ratings of daytime function. This placebo-controlled study of eszopiclone provides compelling evidence that long-term pharmacologic treatment of insomnia is efficacious.

Impedance-based simulation models of supercapacitors and Li-ion batteries for power electronic applications

Abstract: To predict performance of modern power electronic systems, simulation-based design methods are used. This work employs the method of electrochemical impedance spectroscopy to find new equivalent-circuit models for supercapacitors and lithium-ion batteries.

Airborne brake wear debris: size distributions, composition, and a comparison of dynamometer and vehicle tests.

Abstract: Particle size distributions of light-duty vehicle brake wear debris are reported with careful attention paid to avoid sampling biases. Electrical low-pressure impactor and micro-orifice uniform deposit impactor measurements yield consistent size distributions, and the net particulate matter mass from each method is in good agreement with gravimetric filter measurements. The mass mean diameter of wear debris from braking events representative of urban driving is 6 μm, and the number-weighted mean is 1−2 μm for three currently used classes of lining materials: low metallic, semimetallic, and non-asbestos organic (NAO). In contrast, the wear rates are very material dependent, both in number and mass of particles, with 3−4 times higher emissions observed from the low metallic linings as compared to the semimetallic and NAO linings. Wind tunnel and test track measurements demonstrate the appearance of micron size particles that correlate with braking events, with approximately 50% of the wear debris being air...

Consequent-pole permanent-magnet machine with extended field-weakening capability

Abstract: In this paper a description and operating principles of a consequent-pole permanent-magnet machine are presented. In addition, a sizing analysis, finite-element analysis, and experimental results for a prototype machine are addressed. Due to its particular configuration, this machine allows for a wide range of control of the air-gap flux with minimum field ampere-turn requirements and without brushes or slip rings. Two components of the field flux are produced. One, which is almost constant, is produced by the permanent magnet located on the rotor surface. The other, which is variable, is produced by a field winding positioned circumferentially in the center of the stator. These two flux components converge in the air gap. The excitation level of the machine is manipulated by controlling the DC field current. Three-dimensional finite-element analysis and experimental results demonstrate that it is possible to vary the flux over a wide range to keep the terminal voltage constant as the speed increases. A 3 kW 1000-3000 r/min eight-pole and 32 VAC generator using this configuration is tested to verify the flux control capability of this structure.

C-Reactive Protein, Carotid Intima-Media Thickness, and Incidence of Ischemic Stroke in the Elderly The Cardiovascular Health Study

Abstract: Background-Increased carotid artery intima-media thickness (IMT) and elevated C-reactive protein (CRP) are both associated with the occurrence of stroke. We investigated whether elevated CRP is a risk factor for ischemic stroke independent of carotid IMT and studied the interaction between CRP and IMT. Methods and Results-We studied 5417 participants aged 65 years or older without preexisting stroke or chronic atrial fibrillation who were participants in the Cardiovascular Health Study. The hazard ratio of incident ischemic stroke was estimated by Cox proportional hazards regression. During 10.2 years of follow-up, 469 incident ischemic strokes occurred. The adjusted hazard ratios for ischemic stroke in the 2nd to 4th quartiles of baseline CRP, relative to the 1st quartile, were 1.19 (95% CI 0.92 to 1.53), 1.05 (95% CI 0.81 to 1.37), and 1.60 (95% CI 1.23 to 2.08), respectively. With additional adjustment for carotid IMT, there was little confounding. The association of CRP with stroke was significantly different depending on IMT (P<0.02), with no association of CRP with stroke among those in the lowest IMT tertile and a significant association among those with higher levels of IMT. Conclusions-We conclude that elevated CRP is a risk factor for ischemic stroke, independent of atherosclerosis severity as measured by carotid IMT. The association of CRP with stroke is more apparent in the presence of a higher carotid IMT. CRP and carotid IMT may each be independent integrals in determining the risk of ischemic stroke. (Circulation.

HLA-DRB1*1101: A Significant Risk Factor for Sarcoidosis in Blacks and Whites

Abstract: Sarcoidosis is a granulomatous disorder of unknown etiology, associated with an accumulation of CD4+ T cells and a TH1 immune response. Since previous studies of HLA associations with sarcoidosis were limited by serologic or low-resolution molecular identification, we performed high-resolution typing for the HLA-DPB1, HLA-DQB1, HLA-DRB1, and HLA-DRB3 loci and the presence of the DRB4 or DRB5 locus, to define HLA class II associations with sarcoidosis. A Case Control Etiologic Study of Sarcoidosis (ACCESS) enrolled biopsy-confirmed cases (736 total) from 10 centers in the United States. Seven hundred six (706) controls were case matched for age, race, sex, and geographic area. We studied the first 474 ACCESS patients and case-matched controls. The HLA-DRB1 alleles were differentially distributed between cases and controls (P<.0001). The HLA-DRB1*1101 allele was associated (P<.01) with sarcoidosis in blacks and whites and had a population attributable risk of 16% in blacks and 9% in whites. HLA-DRB1-F47 was the amino acid residue most associated with sarcoidosis and independently associated with sarcoidosis in whites. The HLA-DPB1 locus also contributed to susceptibility for sarcoidosis and, in contrast to chronic beryllium disease, a non–E69-containing allele, HLA-DPB1*0101, conveyed most of the risk. Although significant differences were observed in the distribution of HLA class II alleles between blacks and whites, only HLA-DRB1*1501 was differentially associated with sarcoidosis (P<.003). In addition to being susceptibility markers, HLA class II alleles may be markers for different phenotypes of sarcoidosis (DRB1*0401 for eye in blacks and whites, DRB3 for bone marrow in blacks, and DPB1*0101 for hypercalcemia in whites). These studies confirm a genetic predisposition for sarcoidosis and present evidence for the allelic variation at the HLA-DRB1 locus as a major contributor.

Nitric Oxide Enhances Angiogenesis via the Synthesis of Vascular Endothelial Growth Factor and cGMP After Stroke in the Rat

Abstract: We investigated the effects of NO on angiogenesis and the synthesis of vascular endothelial growth factor (VEGF) in a model of focal embolic cerebral ischemia in the rat. Compared with control rats, systemic administration of an NO donor, DETANONOate, to rats 24 hours after stroke significantly enlarged vascular perimeters and increased the number of proliferated cerebral endothelial cells and the numbers of newly generated vessels in the ischemic boundary regions, as evaluated by 3-dimensional laser scanning confocal microscopy. Treatment with DETANONOate significantly increased VEGF levels in the ischemic boundary regions as measured by ELISA. A capillary-like tube formation assay was used to investigate whether DETANONOate increases angiogenesis in ischemic brain via activation of soluble guanylate cyclase. DETANONOate-induced capillary-like tube formation was completely inhibited by a soluble guanylate cyclase inhibitor, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline-1-one (ODQ). Blocking VEGF activity by a neutralized antibody against VEGF receptor 2 significantly attenuated DETANONOate-induced capillary-like tube formation. Moreover, systemic administration of a phosphodiesterase type 5 inhibitor (Sildenafil) to rats 24 hours after stroke significantly increased angiogenesis in the ischemic boundary regions. Sildenafil and an analog of cyclic guanosine monophosphate (cGMP) also induced capillary-like tube formation. These findings suggest that exogenous NO enhances angiogenesis in ischemic brain, which is mediated by the NO/cGMP pathway. Furthermore, our data suggest that NO, in part via VEGF, may enhance angiogenesis in ischemic brain.

Analysis and evaluation of charge balancing circuits on performance, reliability and lifetime of supercapacitor systems

Abstract: Supercapacitors, also known as ultracapacitors or electric double-layer capacitors (ELDCs), are electrical energy storage devices, which offer high power density, extremely high cycling capability, and mechanical robustness. Due to their electrical performance, supercapacitors have a high potential to be used in industrial applications. To improve the performance, reliability, and lifetime of these capacitors, charge-balancing circuits are employed. In this paper, different equalization concepts are analyzed and evaluated. In addition, a simulation approach for the design of supercapacitor systems is proposed. As an example, results from an automotive application are presented.

Impact of comorbidity on lung cancer survival

Abstract: Lung cancer is associated with smoking and age, both of which are associated with comorbidity. We evaluated the impact of comorbidity on lung cancer survival. Data on 56 comorbidities were abstracted from the records of a cohort of 1,155 patients. Survival effects were evaluated with Cox regression (outcome crude death). The adjusted R(2) statistic was used to compare the survival variation explained by predictive variables. No comorbidity was observed in 11.7% of patients, while 54.3% had 3 or more (mean 2.97) comorbidities. In multivariate analysis, 19 comorbidities were associated with survival: HIV/AIDS, tuberculosis, previous metastatic cancer, thyroid/glandular diseases, electrolyte imbalance, anemia, other blood diseases, dementia, neurologic disease, congestive heart failure, COPD, asthma, pulmonary fibrosis, liver disease, gastrointestinal bleeding, renal disease, connective tissue disease, osteoporosis and peripheral vascular disease. Only the latter was protective. Some of the hazards of comorbidities were explained by more directly acting comorbidities and/or receipt of treatment. Stage explained 25.4% of the survival variation. In addition to stage, the 19 comorbidities explained 6.1%, treatments 9.2%, age 3.7% and histology 1.3%. Thirteen uncommon comorbidities (prevalence <6%) affected 21.2% of patients and explained 3.5% of the survival variation. Comorbidity count and the Charlson index were significant predictors but explained only 2.5% and 2.0% of the survival variation, respectively. Comorbidity has a major impact on survival in early- and late-stage disease, and even infrequent deleterious comorbidities are important collectively. Comorbidity count and the Charlson index failed to capture much information. Clinical practice and trials need to consider the effect of comorbidity in lung cancer patients.

Moving kriging interpolation and element‐free Galerkin method

Abstract: A new formulation of the element-free Galerkin (EFG) method is presented in this paper. EFG has been extensively popularized in the literature in recent years due to its flexibility and high convergence rate in solving boundary value problems. However, accurate imposition of essential boundary conditions in the EFG method often presents difficulties because the Kronecker delta property, which is satisfied by finite element shape functions, does not necessarily hold for the EFG shape function. The proposed new formulation of EFG eliminates this shortcoming through the moving kriging (MK) interpolation. Two major properties of the MK interpolation: the Kronecker delta property (Φ I (S J ) = δ I J ) and the consistency property (Σ n I Φ I (x) = I and Σ n I )Φ I (x)x l i = x i ) are proved. Some preliminary numerical results arc given.

Comparison of sol–gel and ion beam deposited MoO3 thin film gas sensors for selective ammonia detection

Abstract: This paper presents a comparative study of the gas-sensing behavior of MoO3 thin films prepared by ion beam deposition and sol–gel techniques, respectively. The sensing response of these films to ammonia in the presence of interfering gases (such as NO2) is assessed. The microstructural characteristics of the sensing materials prepared by these two techniques are determined using electron microscopy and microanalysis techniques. MoO3 is shown to be highly sensitive to ammonia, and the sensitivity depends on processing. The sensing properties of MoO3 thin films and the origin of the p–n-type transition occurring in sol–gel processed films are correlated with the type of the MoO3 polymorph(s) used for sensing.

An Efficient Algorithm for Constructing Optimal Design of Computer Experiments

Abstract: Metamodeling approach has been widely used due to the high computational cost of using high-fidelity simulations in engineering design. The accuracy of metamodels is directly related to the experimental designs used. Optimal experimental designs have been shown to have good “space filling” and projective properties. However, the high cost in constructing them limits their use. In this paper, a new algorithm for constructing optimal experimental designs is developed. There are two major developments involved in this work. One is on developing an efficient global optimal search algorithm, named as enhanced stochastic evolutionary (ESE) algorithm. The other is on developing efficient algorithms for evaluating optimality criteria. The proposed algorithm is compared to two existing algorithms and is found to be much more efficient in terms of the computation time, the number of exchanges needed for generating new designs, and the achieved optimality criteria. The algorithm is also very flexible to construct various classes of optimal designs to retain certain structural properties.Copyright © 2003 by ASME

Multiwavelet grading of pathological images of prostate

Abstract: Histological grading of pathological images is used to determine the level of malignancy of cancerous tissues. This is a very important task in prostate cancer prognosis, since it is used for treatment planning. If infection of cancer is not rejected by noninvasive diagnostic techniques like magnetic resonance imaging, computed tomography scan, and ultrasound, then biopsy specimens of tissue are tested. For prostate, biopsied tissue is stained by hematoxyline and eosine method and viewed by pathologists under a microscope to determine its histological grade. Human grading is very subjective due to interobserver and intraobserver variations and in some cases difficult and time-consuming. Thus, an automatic and repeatable technique is needed for grading. The Gleason grading system is the most common method for histological grading of prostate tissue samples. According to this system, each cancerous specimen is assigned one of five grades. Although some automatic systems have been developed for analysis of pathological images, Gleason grading has not yet been automated; the goal of this research is to automate it. To this end, we calculate energy and entropy features of multiwavelet coefficients of the image. Then, we select most discriminative features by simulated annealing and use a k-nearest neighbor classifier to classify each image to appropriate grade (class). The leaving-one-out technique is used for error rate estimation. We also obtain the results using features extracted by wavelet packets and co-occurrence matrices and compare them with the multiwavelet method. Experimental results show the superiority of the multiwavelet transforms compared with other techniques. For multiwavelets, critically sampled preprocessing outperforms repeated-row preprocessing and has less sensitivity to noise for second level of decomposition. The first level of decomposition is very sensitive to noise and, thus, should not be used for feature extraction. The best multiwavelet method grades prostate pathological images correctly 97% of the time.

Adaptive vehicle communication controlled lighting system

Abstract: A vehicle safety system (10) includes a light source (32). A beam-forming assembly (34) is optically coupled to the light source (32). An object detection sensor (16) detects an object and generates an object detection signal. A controller (18) is coupled to the beam-forming assembly (34) and the object detection sensor (16). The controller (18) adjusts illumination output of the vehicle safety system (10) in response to the object detection signal.

Magnetic resonance imaging and neurosphere therapy of stroke in rat

Abstract: We intracisternally transplanted subventricular zone (SVZ) cells labeled by ferromagnetic particles into stroked rats. Migration of transplanted cells was non-invasively tracked using magnetic resonance imaging (MRI). We found that transplanted cells selectively migrated towards the ischemic parenchyma at a mean speed of 65 +/- 14.6 microm/hr in living rats. Migration of transplanted cells in the brain was also measured histopathologically. Rats transplanted with SVZ cells exhibited significant improvement of neurological function. Our data suggest that intracisternal transplantation of SVZ cells provides an avenue for cell therapy of stroke and that MRI can be used to track grafted cells in the brain.

Integrating environmental aspects into product design and development the new ISO TR 14062

Abstract: It is recommended to transfer the general standard to the company-specific management systems, tools and cultures. Practical experience is necessary to identify its limits in each case. The future development of this Technical Report to a management system standard may not be difficult — and even necessary as shown in the paper. The problem occurs in the variety of opportunities to be implemented. Again, the integration shall be tailored to the existing management systems, in particular ISO 9001/14001. In addition, the design

Dynamic Thermal Model of Li-Ion Battery for Predictive Behavior in Hybrid and Fuel Cell Vehicles

Abstract: Li-Ion battery is attractive for HEVs and FCEVs because of its high power density and lack of memory effect. However, high battery temperatures during operation result in a short battery lifespan and degraded performance.To address this issue, battery manufacturers and OEMs have used different pre-set cooling strategies. Unlike the pre-set cooling strategy this thermal model forecasts battery temperatures, allows a better usage of the battery system, responds to battery power demand and maintains battery temperature limits. This paper discusses the real-time control of the battery cooling including battery stress analysis. The authors present a dynamic thermal model for the Li-Ion battery system using the finite-volume method and discuss transient battery thermal characteristics and real-time battery cooling control under various battery duty cycles. Validation results of the model are presented in this paper.

Enhancing Discrete Choice Demand Modeling for Decision-Based Design

Abstract: Our research is motivated by the need for developing an approach to demand modeling that is critical for assessing the profit a product can bring under the decision-based design framework. Even though demand modeling techniques exist in market research, little work exists on demand modeling that addresses the specific needs of engineering design, in particular, that facilitates engineering decision making. In this work, we enhance the use of discrete choice analysis to demand modeling in the context of decision-based design. The consideration of a hierarchy of product attributes is introduced to map customer desires to engineering design attributes related to engineering analyses. To improve the predictive capability of demand models, the Kano method is employed to provide econometric justification when selecting the shape of the customer utility function. A (passenger) vehicle engine case study, developed in collaboration with the market research firm, J. D. Power & Associates, and the Ford Motor Company, is used to demonstrate the proposed approaches.

Prediction and analysis of human thoracic impact responses and injuries in cadaver impacts using a full human body finite element model

Abstract: Human thoracic dynamic responses and injuries associated with frontal impact, side impact, and belt loading were investigated and predicted using a complete human body finite element model for an average adult male. The human body model was developed to study the impact biomechanics of a vehicular occupant. Its geometry was based on the Visible Human Project (National Library of Medicine) and the topographies from human body anatomical texts. The data was then scaled to an average adult male according to available biomechanical data from the literature. The model includes details of the head, neck, ribcage, abdomen, thoracic and lumbar spine, internal organs of the chest and abdomen, pelvis, and the upper and lower extremities. The present study is focused on the dynamic response and injuries of the thorax. The model was validated at various impact speeds by comparing predicted responses with available experimental cadaver data in frontal and side pendulum impacts, as well as belt loading. Model responses were compared with similar individual cadaver tests instead of using cadaver corridors because the large differences between the upper and lower bounds of the corridors may confound the model validation. The validated model was then used to study thorax dynamic responses and injuries in various simulated impact conditions. Parameters that could induce injuries such as force, deflection, and stress were computed from model simulations and were compared with previously proposed thoracic injury criteria to assess injury potential for the thorax. It has been shown that the model exhibited speed sensitive impact characteristics, and the compressibility of the internal organs significantly influenced the overall impact response in the simulated impact conditions. This study demonstrates that the development of a validated FE human body model could be useful for injury assessment in various cadaveric impacts reported in the literature. Internal organ injuries, which are difficult to detect in experimental studies with human cadavers, can be more easily identified with a validated finite element model through stress-strain analysis, especially in conjunction with experimental studies.

A Study of Early Stage Self-Loosening of Bolted Joints

Abstract: Mechanical Engineering, University of Nevada, Reno, NV 89557 Both experimental investigation and finite element analysis were conducted to explore the mechanisms for the early stage self-loosening of bolted joints under transverse cyclic loading The nuts were glued to the bolts using a strong thread locker in the self-loosening experiments to ensure that no backing-off of the nut occurred Depending on the loading magnitude, the clumping force reduction ranged from 10% to more than 40% of the initial preload after 200 loading cycles Three-dimensional elastic-plastic finite element analysis was conducted with the implementation of an advanced cyclic plasticity model The finite element results revealed that the local cyclic plasticity occurring near the roots of the engaged threads resulted in cyclic strain ratcheting The localized cyclic plastic deformation caused the stresses to redistribute in the bolt, and the result was the gradual loss of clamping force with loading cycles The finite element results agreed with the experimental observations quantitatively When the two clamped plates started to slip and the slip displacement was controlled, both experiments and finite element simulations suggested that the friction between the clamped plates has an insignificant influence on the early stage self-loosening

Impact of the heterogeneous hydrolysis of N2O5 on chemistry and nitrate aerosol formation in the lower troposphere under photosmog conditions

Abstract: [1] The impact of the heterogeneous hydrolysis of N2O5 on tropospheric gas phase and particle phase chemistry was investigated by performing model simulations with two comprehensive model systems and taking into account recent findings on the heterogeneous reaction probability of N2O5. Hereby, we focused on photosmog conditions in the lower troposphere. Chemistry box model runs were carried out neglecting transport and deposition processes. The heterogeneous hydrolysis of N2O5 leads to a decrease of ozone under low-NOx conditions and to a strong increase of ozone under high-NOx conditions. One-dimensional simulations were performed to take into account vertical mixing processes, deposition, and temporal changes of the emissions. The rate constant for the heterogeneous hydrolysis was determined depending on the simulated aerosol surface area density. A large impact of the heterogeneous hydrolysis on the nocturnal concentrations of N2O5, NO3, HNO3, and the surface area density and nitrate content of the aerosol is found. However, the effect of the hydrolysis of N2O5 on ozone decreases considerably compared to the box model simulations. Three-dimensional simulations for a typical summer smog situation for the southwestern part of Germany and on the European scale, which cover a variety of atmospheric and emission conditions, confirm these findings. The impact of heterogeneous hydrolysis on ozone is small, but it causes remarkable changes in the nocturnal concentrations of nitrogen-containing species and on aerosol properties such as surface area density and nitrate content.