bluuebunny/crossref_metadata_2025 huggingface dataset:
Cyclosporin A: a new drug in the field of canine dermatology
Authors: Guaguère Eric , Steffan Jean , Olivry Thierry
Published: March 2004

Abstract In the last few years, there has been growing interest in the use of cyclosporin to treat canine skin diseases. Cyclosporin exhibits potent immunomodulating properties that reflect its ability to block the transcription of cytokines genes in activated T lymphocytes. Cyclosporin also inhibits a number of immune allergic reactions that occur after activation of mast cells, Langerhans cells, eosinophils and keratinocytes. In randomized controlled trials, cyclosporin has proven to be as effective as glucocorticoids for treatment of canine atopic dermatitis at the inducing dosage of 5 mg kg−1. The drug has also proven beneficial for the treatment of perianal fistulas in dogs. Other potential applications are suggested from small pilot open trials using dogs affected with various immune‐mediated dermatological diseases. The pharmacokinetic properties of cyclosporin are very similar in dogs and man, but its safety margin is much wider in dogs. Therefore, routine cyclosporin blood level monitoring does not appear necessary. Although in man renal impairment and hypertension are often seen, even at low doses, these effects are not observed in dogs. Adverse reactions consist mainly of transient emesis and diarrhoea occurring during the first days of treatment. Other adverse reactions, such as gingival hyperplasia, verruciform lesions and hypertrichosis, appear to be dose‐dependent, and occur rarely at therapeutic doses. An increased susceptibility to infections has not been reported in dogs receiving this drug.
New activities of a catalytic antibody with a peroxidase activity
Authors: Ricoux Rémy , Lukowska Edyta , Pezzotti Fabio , Mahy Jean‐Pierre
Published: March 2004

In order to estimate the size of the cavity remaining around the heme of the 3A3–microperoxidase 8 (MP8) hemoabzyme, the formation of 3A3–MP8–Fe(II)‐nitrosoalkane complexes upon oxidation of N‐monosubstituted hydroxylamines was examined. This constituted a new reaction for hemoabzymes and is the first example of fully characterized Fe(II)–metabolite complexes of antibody–porphyrin. Also, via a comparison of the reactions with N‐substituted hydroxylamines of various size and hydrophobicity, antibody 3A3 was confirmed to bring about a partial steric hindrance on the distal face of MP8. Subsequently, the influence of the antibody on the stereoselectivity of the S‐oxidation of sulfides was examined. Our results showed that MP8 alone and the antibody–MP8 complex catalyze the oxidation of thioanisole by H2O2 and tert‐butyl hydroperoxide, following a peroxidase‐like two‐step oxygen‐transfer mechanism involving a radical–cation intermediate. The best system, associating H2O2 as oxidant and 3A3–MP8 as a catalyst, in the presence of 5% tert‐butyl alcohol, led to the stereoselective S‐oxidation of thioanisole with a 45% enantiomeric excess in favour of the R isomer. This constitutes the highest enantiomeric excess reported to date for the oxidation of sulfides catalyzed by hemoabzymes.
Characterization of Mesorhizobium huakuii lipid A containing both d‐galacturonic acid and phosphate residues
Authors: Choma Adam , Sowinski Pawel
Published: March 2004

The chemical structure of the free lipid A isolated from Mesorhizobium huakuii IFO 15243T was elucidated. Lipid A is a mixture of at least six species of molecules whose structures differ both in the phosphorylation of sugar backbone and in fatty acylation. The backbone consists of a β (1′→6) linked 2,3‐diamino‐2,3‐dideoxyglucose (DAG) disaccharide that is partly substituted by phosphate at position 4′. The aglycon of the DAG‐disaccharide has been identified as α‐d‐galacturonic acid. All lipid A species carry four amide‐linked 3‐hydroxyl fatty residues. Two of them have short hydrocarbon chains (i.e. 3‐OH‐i‐13:0) while the other two have longer ones (i.e. 3‐OH‐20:0). Distribution of 3‐hydroxyl fatty acids between the reducing and nonreducing DAG is symmetrical. The nonpolar as well as (ω‐1) hydroxyl long chain fatty acids are components of acyloxyacyl moieties. Two acyloxyacyl residues occur exclusively in the nonreducing moiety of the sugar backbone but their distribution has not been established yet. The distal DAG amide‐bound fatty acid hydroxyls are not stoichiometrically substituted by ester‐linked acyl components.
Induction of endothelial apoptosis by 4‐hydroxyhexenal
Authors: Lee Ji Young , Je Jeong Hwan , Kim Dae Hyun , Chung Sang Woon , Zou Yani , Kim Nam Deuk , Ae Yoo Mie , Suck Baik Hyung , Yu Byung Pal , Chung Hae Young
Published: March 2004

Lipid peroxidation and its products such as 4‐hydroxy‐2‐nonenal (HNE) and 4‐hydroxyhexenal (HHE) are known to affect redox balance during aging and various degenerative processes, including vascular dysfunction. Deterioration of the endothelial cells that line the vascular wall is known to be an underlying cause of vascular dysfunction. At present, little is known about the mechanism by which HHE induces endothelial cell death (i.e. apoptosis), although HNE‐induced apoptotic cell death has been reported. The aim of this study was to determine whether apoptosis induced by HHE in endothelial cells involves peroxynitrite (ONOO–). Our results show that in endothelial cells HHE triggers apoptotic cell death by inducing apoptotic Bax coupled with a decrease in anti‐apoptotic Bcl‐2. Results show that HHE induces reactive oxygen species (ROS), nitric oxide, and ONOO– generation, leading to redox imbalance. Furthermore, the antioxidant N‐acetyl cysteine, ROS scavenger, and penicillamine, an ONOO– scavenger, were found to block HHE‐mediated apoptosis. We used confocal laser microscopy to estimate the ability of these inhibitors to attenuate HHE‐induced intracellular ONOO– levels thus confirming the oxidative mediation of apoptosis in endothelial cells. These findings strongly suggest that accumulated HHE triggers reactive species‐mediated endothelial apoptosis, leading to vascular dysfunction as well as vascular aging. During aging, increased lipid peroxidation and its associated production of HHE may exacerbate the weakened redox balance, leading to various chronic degenerative processes including vascular dysfunction.
Jackbean, soybean and Bacillus pasteurii ureases
Authors: Follmer Cristian , Real‐Guerra Rafael , Wasserman German E. , Olivera‐Severo Deiber , Carlini Célia R.
Published: March 2004

In this work we compared two plant ureases, jackbean urease (JBU) and embryo‐specific soybean urease (SBU) and a bacterial (Bacillus pasteurii) urease, for kinetic parameters and other biological properties described recently for ureases that are independent of the ureolytic activity. The insecticidal effect of ureases was investigated in feeding trials with the cotton sucker bug, Dysdercus peruvianus (Hemiptera) as an insect model. Contrasting with B. pasteurii urease (PBU), both plant ureases presented potent insecticidal activity, with LD50 values of 0.017% (w/w) and 0.052% (w/w) for JBU and SBU, respectively. The insecticidal property of JBU or SBU was not affected by treatment with p‐hydroxymercuribenzoate, an irreversible inhibitor of ureolytic activity of both proteins. Also, contrasting with canatoxin – a urease isoform from jackbean seeds that displays a toxic effect in mice (LD50 = 2 mg·kg−1) – no lethality was seen in mice injected intraperitoneally with JBU or SBU (20 mg·kg−1). Similarly to canatoxin, the three enzymes promoted aggregation of blood platelets (EC50 = 400.0 µg·mL−1, 22.2 µg·mL−1, 15.8 µg·mL−1 for BPU, SBU and JBU, respectively). This platelet activating property was also independent of urease activity. Comparison of the kinetic properties indicated that SBU is fivefold less susceptible than JBU to inhibition by acetohydroxamic acid, a chelator of Ni+2 and Zn+2 ions. The ureases also showed different susceptibility to agents that modify cysteine residues, such as p‐hydroxymercuribenzoate and p‐benzoquinone. Altogether, these data emphasize that biological properties that are independent of ureolytic activity are not restricted to jackbean ureases and that these proteins may have a role in plant defense against insect predators.
Membrane binding of SRP pathway components in the halophilic archaea Haloferax volcanii
Authors: Lichi Tovit , Ring Gabriela , Eichler Jerry
Published: March 2004

Across evolution, the signal recognition particle pathway targets extra‐cytoplasmic proteins to membranous translocation sites. Whereas the pathway has been extensively studied in Eukarya and Bacteria, little is known of this system in Archaea. In the following, membrane association of FtsY, the prokaryal signal recognition particle receptor, and SRP54, a central component of the signal recognition particle, was addressed in the halophilic archaea Haloferax volcanii. Purified H. volcanii FtsY, the FtsY C‐terminal GTP‐binding domain (NG domain) or SRP54, were combined separately or in different combinations with H. volcanii inverted membrane vesicles and examined by gradient floatation to differentiate between soluble and membrane‐bound protein. Such studies revealed that both FtsY and the FtsY NG domain bound to H. volcanii vesicles in a manner unaffected by proteolytic pretreatment of the membranes, implying that in Archaea, FtsY association is mediated through the membrane lipids. Indeed, membrane association of FtsY was also detected in intact H. volcanii cells. The contribution of the NG domain to FtsY binding in halophilic archaea may be considerable, given the low number of basic charges found at the start of the N‐terminal acidic domain of haloarchaeal FtsY proteins (the region of the protein thought to mediate FtsY–membrane association in Bacteria). Moreover, FtsY, but not the NG domain, was shown to mediate membrane association of H. volcanii SRP54, a protein that did not otherwise interact with the membrane.
Adequacy of rehabilitation monitoring practices in the Western Australian mining industry
Authors: Thompson Scott A. , Thompson Graham G.
Published: March 2004

Summary  Currently in Western Australia (WA) there are no mandated standards for assessing rehabilitation success for the mining industry. We argue a case for focusing on the creation of near‐natural, self‐sustaining, functional ecosystems as the primary objective for rehabilitation programs and where this is not achievable, mines should plan to be ‘environmentally neutral’ by undertaking some improvements to degraded landscapes. We suggest that flora and fauna monitoring are appropriate tools for managers and regulators to obtain information on the extent to which a rehabilitated area has achieved a near natural, self‐sustaining, functional ecosystem similar to that in the adjacent undisturbed area. This monitoring can also be used for completion criteria and closure plans. We report results from a short questionnaire sent to mine site environmental managers to assess the extent of flora and fauna monitoring in rehabilitation areas. Survey results highlighted the need for a more systematic and consistent approach to the monitoring of flora and fauna in rehabilitated mining areas in WA. Of 36 respondents, 23 mines monitored flora, three monitored fauna and two monitored both.
Predicting the biodiversity benefits of the Saltshaker Project, Boorowa, NSW
Authors: Freudenberger David , Harvey Judith , Drew Alex
Published: March 2004

Did the 2‐year Saltshaker Project nudge the Boorowa Catchment along a new pathway towards improved biodiversity?
Flora diversity of farm forestry plantations in southeast Queensland
Authors: Wang Jian , Borsboom Adrian C. , Smith Geoffrey C.
Published: March 2004

Summary  Plant species composition in plantation monoculture of the native Gympie Messmate (Eucalyptus cloeziana F. Muell.) was assessed and compared with native eucalypt forest and cleared grazing land in southeast Queensland, Australia. A total of 18 sites (11 in the plantations, four in native eucalypt forests and three on cleared grazing land) were surveyed. The four plantation age classes during the 18‐month survey period were 0.3–1.8 (very young), 2.1–3.8 (young), 15–16.5 (mid‐aged) and 38–40.5 (old) years of age. Significantly more native plant species were recorded in the plantations, regardless of their age, than on cleared grazing land. The number of native plant species in the old plantations was not significantly different from the native eucalypt forests. Native tree and shrub species richness increased significantly with plantation age. Two species (Ricinocarpos speciosus Muell. Arg. and Xanthostemon oppositifolius F. M. Bailey) listed as Vulnerable and one species (Alyxia magnifolia F. M. Bailey) listed as Rare were recorded in the old plantations. Two Rare species (A. magnifolia and Acianthus amplexicaulis (F. M. Bailey) Rolfe) were recorded in the native eucalypt forests. Exotic plant species, consisting mainly of herbs, grasses and shrubs in the plantations, were significantly more abundant in the very young and young plantations. However, the number of exotic species decreased significantly with increasing age of the plantations. The results suggest that even small‐scale plantation can increase landscape heterogeneity and help protect biodiversity.
Experience and inference: how far will science carry us?
Authors: Lichtenberg Joseph
Published: March 2004

Abstract:  This paper begins with a view of the remarkable understanding of infant and child development that has evolved from research and observation. The limitations of this contribution from science to the multi‐dimensional context‐based individuality of each human in his or her intersubjective realm are then considered. For a contemporary view we must recognize the influence of the variability of experiences and the inferences drawn from them. Inferences involve symbolization and culturally derived archetypes as illustrated in a clinical example.
‘Dialectical process’ and ‘constructive method’: micro‐analysis of relational process in an example from parent–infant psychotherapy
Authors: Woodhead Judith
Published: March 2004

Abstract:  Jung defined experience that takes place between therapist and patient as ‘dialectical process’, achieved through ‘constructive method’. Perspectives from attachment theory, neurobiology, cognitive science, systems thinking and infancy research confirm and extend his view of the centrality of relational process in the development of self. Interactional experiences are embedded within the history of the primary parent–infant relationship and structure within the mind implicit patterns of relating. These patterns influence capacities for managing a whole lifetime of affective relational experience within the self and with others. This paper shows how parent–infant psychotherapy seeks to intervene during the formation of disturbed relational patterns. I offer detailed micro‐analysis of the moment‐to‐moment ‘dialectical process’ that a mother, her four‐month‐old infant and myself ‘constructed’ together.
The science and meaning of the self
Authors: Jones Raya
Published: March 2004

Abstract:  Scientists and practitioners alike invest in theorizing the self in psychology, but prioritize differently theoretical and practical objectives. Theorizing the self differs also when mapped onto the ‘science versus art’ debate, viewed historically and with reference to the philosophy of science. Jung's model of the psyche is compared and contrasted with social cognitive models of self‐concept. Finally, some implications of social constructionism are considered.
Chaos and self‐organization: emergent patterns at critical life transitions
Authors: Skar Patricia
Published: March 2004

Abstract:  A feeling of chaos can accompany many real‐life events over which we have little or no control, and latent developmental needs may create tension that manifests in symptoms of depression or anxiety. Particularly at critical life transitions, conflicts may arise which have no obvious solution. From an analytic perspective, recent scientific models from the area of complexity theory can prove illuminating as analogies to Jung's archetypal view of the individuation process. Throughout life, human beings, like many complex, open systems, pass from disordered phases to more complex stages of order. This paper shows how the scientific concept of self‐organization can be compared with our physical and psychological developmental processes. From embryology, the model of the ‘epigenetic landscape’ (C.H. Waddington) is introduced as an analogy to Jung's individuation process, with a clinical example to illustrate these parallels. The emergent nature of behaviour and development is seen from the viewpoint of the organism as a dynamical system, and Jung's concept of the archetype viewed as an emergent property of the activity of the brain/mind.
Fiscal Planning, Budgeting, and Rebudgeting Using Revenue Semaphores
Authors: Cornia Gary C. , Nelson Ray D. , Wilko Andrea
Published: March 2004

Revenue forecasts play an important role in the state government budget and policy process. These forecasts are generally reported to executive and legislative leaders as point estimates, with no acknowledgment of their corresponding risk and uncertainty. The revenue semaphores proposed in this article outline procedures by which revenue uncertainty directly influences the planning process. The goal is not to make forecasts more accurate, but to make discussions of budget and revenue alternatives more comprehensive. Explicitly incorporating risk and uncertainty measures into the budgeting process increases the degree of real‐time budgeting and reduces some adverse effects of budget revisions after the fiscal year begins. The discussion occurs in the context of budget control, management, and policy making.
Career Paths of City Managers in America's Largest Council‐Manager Cities
Authors: Watson Douglas J. , Hassett Wendy L.
Published: March 2004

What are the typical career paths of city managers serving in the nation's largest cities? This article examines the career paths of 113 city managers in council‐manager cities with populations over 100,000. The authors identify four distinct career paths for city managers—long servers, lateral movers, ladder climbers, and‐single city careerists—and find that city managers in the largest council‐manager cities are commonly ladder climbers or single‐city careerists. This research shows the stereotypical description of the ladder climber as the only career path is incomplete. Many large cities are providing opportunities for career development, making it unnecessary for city councils to select outsiders to fill top positions. While other research has shown that nearly four‐fifths of city managers are hired from outside, only 54 percent of the city managers in the largest cities were outsiders at the time they were hired.
Service Quality and Benchmarking the Performance of Municipal Services
Authors: Folz David H.
Published: March 2004

How can local officials select benchmarking partners whose best practices have the most potential for applicability and success in improving service performance? This study suggests the process for selecting the most appropriate benchmarking partners and for making fair performance comparisons will be advanced if local officials initially address the issue of what level of input service quality level is desired or can be provided. Using data collected from a national survey, the study presents a framework for measuring service quality for municipal solid waste recycling programs. It examines the connection between input service quality and service outcomes and describes the results of analyses of the contextual factors and best practices that distinguish the top recycling performers and potential benchmarking partners in each service‐quality class. The study suggests a model for how local officials can use this type of information to select an appropriate benchmarking partner. The study shows that a quality‐of‐service framework for municipal services can advance local decision making about what citizens and stakeholders expect and will support in terms of input service quality. It also can help local officials identify benchmarking partners that provide a service at the desired level of quality.
State Wildlife Policy and Management: The Scope and Bias of Political Conflict
Authors: Nie Martin
Published: March 2004

State wildlife policy and management are often characterized by divisive political conflict among competing stakeholders. This conflict is increasingly being resolved through the ballot‐initiative process. One important reason the process is being used so often is the way state wildlife policy and management decisions are often made by state wildlife commissions, boards, or councils (the dominant way these decisions are made in the United States). These bodies are often perceived by important stakeholders as biased, exclusive, or unrepresentative of nonconsumptive stakeholder values. As a result, unsatisfied interest groups often try to take decision‐making authority away from these institutions and give it to the public through the ballot initiative. Cases and examples from Alaska, Arizona, Colorado, and Idaho are examined in this context. The article finishes by outlining four broad alternatives that may be debated in the future: the no change alternative, the authoritative expert alternative, the structural change alternative, and the stakeholder‐based collaborative conservation alternative(s).
Representative Bureaucracy: Understanding Its Past to Address Its Future
Authors: Bailey Margo
Published: March 2004

Julie Dolan and David H. Rosenbloom, eds., Representative Bureaucracy: Classic Readings and Continuing Controversies

Norma M. Riccucci, Managing Diversity in Public Sector Workforces

Margaret C. Rung, Servants of the State: Managing Diversity and Democracy in the Federal Workforce, 1933–1953
Membrane Domains in Lymphocytes – From Lipid Rafts to Protein Scaffolds
Authors: Harder Thomas , Engelhardt Karin R.
Published: March 2004

Lateral compartmentalization of the plasma membrane into domains is a key feature of immune cell activation and subsequent immune effector functions. Here, we will review the high diversity of membrane domains, ranging from elementary lipid rafts, envisioned as dynamic and small domains (in the tens of nm), to relatively stable μm‐scale membrane domains, which form the immunologic synapse of T lymphocytes. We will discuss the relationship between these different types of plasma membrane domains and how raft lipid‐ and protein‐controlled interactions and cell biological processes cooperate to generate functional domains that mediate lymphocyte activity.
Characterization of BLOC‐2, a Complex Containing the Hermansky–Pudlak Syndrome Proteins HPS3, HPS5 and HPS6
Authors: Di Pietro Santiago M. , Falcón‐Pérez Juan M. , Dell'Angelica Esteban C.
Published: March 2004

Hermansky–Pudlak syndrome (HPS) defines a group of at least seven autosomal recessive disorders characterized by albinism and prolonged bleeding due to defects in the lysosome‐related organelles, melanosomes and platelet‐dense granules, respectively. Most HPS genes, including HPS3, HPS5 and HPS6, encode ubiquitously expressed novel proteins of unknown function. Here, we report the biochemical characterization of a stable protein complex named Biogenesis of Lysosome‐related Organelles Complex‐2 (BLOC‐2), which contains the HPS3, HPS5 and HPS6 proteins as subunits. The endogenous HPS3, HPS5 and HPS6 proteins from human HeLa cells coimmunoprecipitated with each other from crude extracts as well as from fractions resulting from size‐exclusion chromatography and density gradient centrifugation. The native molecular mass of BLOC‐2 was estimated to be 340 ± 64 kDa. As inferred from the biochemical properties of the HPS6 subunit, BLOC‐2 exists in a soluble pool and associates to membranes as a peripheral membrane protein. Fibroblasts deficient in the BLOC‐2 subunits HPS3 or HPS6 displayed normal basal secretion of the lysosomal enzyme β‐hexosaminidase. Our results suggest a common biological basis underlying the pathogenesis of HPS‐3, ‐5 and ‐6 disease.
Where Are the Gaps? The Effects of HIV‐prevention Interventions on Behavioral Change
Authors: Bollinger Lori , Cooper‐Arnold Katharine , Stover John
Published: March 2004

As more funding becomes available for HIV/AIDS programs in developing countries, an understanding of how prevention interventions lead to behavioral change and how behavioral change leads to reductions in HIV prevalence is crucial. This study presents the results of an extensive effort to develop a matrix to relate coverage of key HIV/AIDS‐prevention services to changes in behavior among different risk groups and to describe the gaps that exist in the literature. Many studies could not be included in the matrix because they did not meet the necessary criteria. Evaluation of interventions targeting abstinence programs, workplace programs, and certain groups at high risk of infection would prove invaluable.
Condom Promotion for AIDS Prevention in the Developing World: Is It Working?
Authors: Hearst Norman , Chen Sanny
Published: March 2004

Two decades of experience and research provide new insights into the role of condoms for AIDS prevention in the developing world. This literature review and synthesis is based on computerized searches of the scientific literature and review of conference presentations, publications of national and international organizations, and popular media. Condoms are about 90 percent effective for preventing HIV transmission, and their use has grown rapidly in many countries. Condoms have produced substantial benefit in countries like Thailand, where both transmission and condom promotion are concentrated in the area of commercial sex. The public health benefit of condom promotion in settings with widespread heterosexual transmission, however, remains unestablished. In countries like Uganda that have curbed generalized epidemics, reducing the number of individuals' sex partners appears to have been more important than promoting the use of condoms. Other countries continue to have high rates of HIV transmission despite high reported rates of condom use among the sexually active. The impact of condoms may be limited by inconsistent use, low use among those at highest risk, and negative interactions with other strategies. Recommendations include increased condom promotion for groups at high risk, more rigorous measurement of the impact of condom promotion, and more research on how best to integrate condom promotion with other prevention strategies.
Assessing the Potential of Condom Use to Prevent the Spread of HIV: A Microsimulation Study
Authors: Bracher Michael , Santow Gigi , Watkins Susan Cotts
Published: March 2004

In this study, a microsimulation model is used to assess the potential impact of condom use on women's lifetime risk of acquiring HIV in rural southern Malawi. The model draws on survey data for information on sexual activity, marriage and divorce, and on the biomedical literature for input parameters governing the transmission and spread of HIV and other sexually transmitted diseases (STDs). We show that lifetime risk could be as high as 42 percent with no condom use and as low as 8 percent if everyone consistently uses condoms with nonmarital partners. Next, we examine the impact of more realistic, intermediate strategies of condom use, varying men's propensity to use a condom with nonmarital partners, varying the per‐coitus probability of condom use, varying probabilities of slippage or breakage, and finally, examining the effect of condom use in the presence of STD symptoms. We demonstrate profound effects of consistent condom use and of condom use prompted by symptomatic STDs.
Book Review
Authors: Jones Heidi
Published: March 2004

Shireen Jejeebhoy, Michael Koenig, and Christopher Elias, editors Reproductive Tract Infections and Other Gynaecological Disorders: A Multidisciplinary Research Approach
End Milling of Elastomers—Fixture Design and Tool Effectiveness for Material Removal
Authors: Shih Albert J. , Lewis Mark A. , Strenkowski John S.
Published: March 2004

This paper describes the machining of elastomers using sharp, woodworking tools and the machining of cryogenically cooled elastomers. Due to the lack of information on tool selection for elastomer machining, a set of thirteen tools that cover different sizes and tool geometries and materials was used in this study. Fixture design was found to be critical in machining of elastomers because of its relatively low elastic modulus. The cutting force created during machining can generate significant deformations in the elastomer workpiece. The finite element technique is used to analyze the structural stiffness of the elastomer workpiece under different geometric configurations. The effective stiffness is defined to quantify and compare the stiffness of elastomer workpiece machined by different tool sizes. The cleanliness of the groove machined by end milling is investigated. Use of some down-cut end-milling tools effectively removed the elastomer material at room temperature and generated a clean groove. The tool configuration and part fixturing are identified as the two most important variables that affect the cleanliness of machined grooves. Cooling the elastomer workpiece by solid carbon dioxide (dry ice) to about −78.6°C improved the machined surface finish.
Modeling of Deformation of Ring Shaped Workpieces Due to Chucking and Cutting Forces
Authors: Malluck John A. , Melkote Shreyes N.
Published: March 2004

This paper presents a theoretical model for predicting static elastic deformations of ring-type workpieces due to in-plane chucking and cutting forces applied in turning processes. The model is derived from classical elasticity theory for bending of thin rings. Experimental results are presented to verify the strengths and limitations of the model. The results from a finite element model are also presented for comparison. The theoretical model is shown to be accurate to within 6% of the measured radial deformation due to chucking loads for rings with inner-to-outer diameter ratio Din/Dout of 0.881. The finite element model is shown to yield slightly better results for higher diameter ratios. The theoretical model is also verified under actual cutting loads and shown to be in good agreement with measurements.
Individual Station Monitoring Using Press Tonnage Sensors for Multiple Operation Stamping Processes
Authors: Jin Jionghua
Published: March 2004

In multiple operation stamping processes, a press tonnage signal measured by press tonnage sensors installed on press linkages/uprights, is the summation of die forces at all stations. Different from the current practice of using a whole cycle of press tonnage signals to monitor the compound condition of all stations, this paper proposes a new method to use the partitioned monitoring segments of press tonnage signals to monitor individual station conditions. For this purpose, a generic signal segmentation principle is proposed, and the Hotelling T2 control charts are developed with consideration of the interactions among stations. A real case study of a doorknob stamping process is provided to demonstrate analysis procedures and effectiveness of the developed methodology.
Laser-Assisted Machining of Magnesia-Partially-Stabilized Zirconia
Authors: Pfefferkorn Frank E. , Shin Yung C. , Tian Yinggang , Incropera Frank P.
Published: March 2004

Laser-assisted machining (LAM) of magnesia-partially-stabilized zirconia (PSZ) is investigated to determine the effect of heating on machinability, as determined by tool wear, cutting energy, surface integrity, and material removal mechanisms. It is found that PSZ can be successfully machined with a polycrystalline cubic boron nitride tool and that tool life increases with material removal temperature up to a maximum of 121 minutes. The benefit of laser-assistance in material removal is also demonstrated by the 2.5 fold decrease in the specific cutting energy with increased temperature. It is shown surface roughness varies significantly with tool wear with little dependence on cutting temperature unlike in LAM of other ceramics. Evidence of mixed brittle and ductile material removal mechanisms is presented, and the optimum condition within the test matrix is established.
Integrated Dynamic Thermo-Mechanical Modeling of High Speed Spindles, Part 2: Solution Procedure and Validations
Authors: Li Hongqi , Shin Yung C.
Published: March 2004

This paper presents a new solution procedure for an integrated thermo-dynamic spindle model and validation results. Based on the model presented in Part 1 of this paper, a computer program has been developed to generate comprehensive solutions for high speed spindle-bearing systems, such as bearing stiffness, contact load and temperature, spindle dynamic characteristics and response, temperature distributions, and thermal expansions. The model and the solution procedure are modular such that solutions for different spindle set-ups can be easily generated by combining a given spindle model with different toolholder models. Validation test results for thermal and dynamic predictions are presented for four different spindle systems, including the thermal and dynamic validation tests on a specially constructed spindle testbed. The validation results show the model has accurate predictive capabilities for a wide range of operating conditions and various spindle designs.
Measurement Scheme Synthesis in Multi-Station Machining Systems
Authors: Djurdjanovic Dragan , Ni Jun
Published: March 2004

Different sets of measurements carry different amounts of information about the root causes of quality problems in machining. The selection of measurements in multi-station machining systems is currently a slow and error-prone process based on expert human knowledge. In this paper, we propose systematic procedures for synthesizing measurement schemes that carry the most information about the root causes of dimensional machining errors. The amount of root cause information conveyed by a given set of measurements was assessed using the recently introduced formal methods for quantitative characterization of measurement schemes in multi-station machining systems. The newly proposed measurement scheme synthesis procedures were applied to devising measurement schemes in an automotive cylinder head machining process. It was observed that the measurement scheme synthesis procedure based on a genetic algorithm robustly outperformed the synthesis procedures based on the heuristics of successive measurement removal.
Structural Modeling of Profiled Edge Laminate (PEL) Tools Using the Finite Element Method
Authors: Shook Jeremy T. , Walczyk Daniel F.
Published: March 2004

Profiled Edge Laminate (PEL) tooling is a rapid tooling method that uses a stacked array of vertically orientated thick laminae with profiled and beveled top edges to provide the desired surface shape for part forming or molding. Since this method is being developed for commercial use, there is a need to be able to predict the response of PEL tools to both structural and thermal loads encountered during a manufacturing process. In this paper, a general approach for structural modeling of PEL tools is developed using the Finite Element Method (FEM). To validate this method, an experimental case study is performed. Specifically, a PEL test tool is subjected to two-dimensional structural loading to simulate a sheet metal hydroforming process, while tool displacements and strains are recorded. The experimental results are compared to those obtained using the FEM modeling approach, conclusions are drawn about its effectiveness, and more advanced modeling work is proposed.
Thermal Plastic-Elastic Analysis in Consideration of Metallurgical Microstructure
Authors: Takahashi Tsuyoshi , Sugimura Yoshio , Sasaki Katsuhiko
Published: March 2004

Depending on casting methods, aluminum alloy cylinder heads differ greatly in quality and local strength as well as overall strength. Obviously, casting methods largely affect the durability of a cylinder head. Therefore, in order to precisely evaluate the durability of a newly-designed cylinder head by CAE, it is necessary to introduce a new method with the effects of a casting method taken into account. In our research, a method has been devised to be used in CAE in such processes from engineering to manufacturing for evaluation. More specifically, by using the method, metallurgical microstructure of cast aluminum alloy is analyzed by dividing cylinder head into such domains as lower deck, middle and upper deck parts for mechanical properties and a casting defect of porosity. The domain profile information on mechanical properties and porosity has helped us improve accuracy in the structural analysis.
Comparative Statistical Analysis of Test Parts Manufactured in Production Environments
Authors: Gilsinn David E. , Ling Alice V.
Published: March 2004

Estimating error uncertainties arising in production parts is not a well-understood process. An approach to estimate these uncertainties was developed in this study. Machine tool error components were measured on a three-axis vertical machining center. Multiple parts were produced on the measured machining center then measured on a coordinate measuring machine. Uncertainty models for hole-center to hole-center lengths and orthogonalities were developed using measured machine tool errors. These estimated uncertainties were compared against measured uncertainties. The main conclusion from the study is that the Law of Propagation of Uncertainties can be used to estimate machining uncertainties.
Microscale Laser Shock Peening of Thin Films, Part 1: Experiment, Modeling and Simulation
Authors: Zhang Wenwu , Yao Y. Lawrence , Noyan I. C.
Published: March 2004

Microscale Laser Shock Peening (LSP), also known as Laser Shock Processing, is a technique that can be potentially applied to manipulate residual stress distributions in metal film structures and thus improve the fatigue performances of micro-devices made of such films. In this study, microscale LSP of copper films on single crystal silicon substrate is investigated. Before and after-process curvature measurement verifies that sizable compressive residual stress can be induced in copper thin films using microscale LSP. Improved modeling work of shock pressure is summarized and the computed shock pressure is used as loading in 3D stress/strain analysis of the layered film structure. Simulation shows that the stress/strain distribution in the metal film is close to equi-biaxial and is coupled into the silicon substrate.
In-Plane Stiffness and Yield Strength of Periodic Metal Honeycombs
Authors: Wang A.-J. , McDowell D. L.
Published: March 2004

In-plane mechanical properties of periodic honeycomb structures with seven different cell types are investigated in this paper. Emphasis is placed on honeycombs with relative density between 0.1 and 0.3, such that initial yield is associated with short column compression or bending, occurring prior to elastic buckling. Effective elastic stiffness and initial yield strength of these metal honeycombs under in-plane compression, shear, and diagonal compression (for cell structures that manifest in-plane anisotropy) are reported as functions of relative density. Comparison among different honeycomb structures demonstrates that the diamond cells, hexagonal periodic supercells composed of six equilateral triangles and the Kagome cells have superior in-plane mechanical properties among the set considered.
A Study of Inhomogeneous Plastic Deformation of 1045 Steel
Authors: Zhang Jixi , Jiang Yanyao
Published: March 2004

An experimental study was conducted on the inhomogeneous plastic deformation of 1045 steel subjected to monotonic tension and cyclic tension-compression. Small strain gages were used to characterize the local deformation and transmission electron microscopy (TEM) was used to study the microstructures associated with the observed deformation phenomenon. Under monotonic tension, the strain of the Lu¨ders front was lower than the full Lu¨ders strain. The local strains were inhomogeneous even at the work-hardening stage. Under stress-controlled cyclic loading with stress amplitudes below the lower yield stress, cyclic deformation consisted of an incubation stage, a significantly inhomogeneous cyclic softening stage, and a saturation stage. Inhomogeneous cyclic plasticity persisted at the saturation stage. A monotonic tension preload can eliminate the incubation stage in the subsequent cyclic loading. Under asymmetric cyclic loading with a mean stress, the cyclic plastic deformation was accompanied by noticeable inhomogeneous ratcheting deformation. TEM was used to analyze the distribution and evolution of the dislocation structures at different locations of the specimen. With increasing loading cycles, the dislocation substructures evolved in a sequence of loose tangles, thick veins, long walls, elongated cells, and equiaxial cells. Based upon the mechanical experiments and observations of dislocation arrangements, the mechanisms governing inhomogeneous cyclic plastic deformation were discussed.
Micromechanical Simulation of Dynamic Fracture Using the Cohesive Finite Element Method
Authors: Zhai Jun , Tomar Vikas , Zhou Min
Published: March 2004

Dynamic fracture in two-phase Al2O3/TiB2 ceramic composite microstructures is analyzed explicitly using a cohesive finite element method (CFEM). This framework allows the effects of microstructural heterogeneity, phase morphology, phase distribution, and size scale to be quantified. The analyses consider arbitrary microstructural phase morphologies and entail explicit tracking of crack growth and arbitrary fracture patterns. The approach involves the use of CFEM models that integrate cohesive surfaces along all finite element boundaries as an intrinsic part of the material description. This approach obviates the need for any specific fracture criteria and assigns models the capability of predicting fracture paths and fracture patterns. Calculations are carried out using idealized phase morphologies as well as real phase morphologies in actual material microstructures. Issues analyzed include the influence of microstructural morphology on the fracture behavior, the influence of phase size on fracture resistance, the effect of interphase bonding strength on failure, and the effect of loading rate on fracture.
An Assessment of In-Service Stress Relaxation of a Work-Hardened Aluminum Magnesium Alloy
Authors: Zhu L. , Beaudoin A. J. , MacEwen S. R.
Published: March 2004

Time-dependent relaxation processes continue after forming of sheet metal components. Mechanical properties and even the shape of the part may evolve with time. Beverage can ends, made of an aluminum-magnesium alloy, provide one example of relaxation in a metal product. Ends are manufactured in a series of forming operations, and the can end buckle pressure plays an important role in the design. It has been established that buckle pressure decreases with time in service. In this work, we outline a simple bending test to study relaxation at stress levels well below the usual 0.2 percent offset yield stress. The evolution of stress and development of plastic strain with time are assessed through a simple analysis of springback. The microplastic processes that lead to permanent deformation of the bent beam are well characterized by a model developed by Garmestani and Hart.
On the Characterization of Fatigue Crack Growth in a Plate With a Single-Sided Repair
Authors: Duong C. N. , Wang C. H.
Published: March 2004

An unsupported cracked plate repaired with a reinforcement bonded on one side may experience considerable out-of-plane bending due to the load-path eccentricity. This out-of-plane bending causes the stress intensity factor at the crack tip to vary significantly through the plate’s thickness with a maximum value attained at the un-patched side of the crack. Even though significant analytical work has been done in the past to evaluate these thickness-varying stress intensity factors, however, to the authors’ knowledge, little work has been done to characterize the fatigue crack growth in a plate with a single-sided repair. The purposes of the present work are to (i) assess the accuracy of the available analytical methods for predicting the stress intensity factors of the panels with a single-sided repair and more importantly, and (ii) characterize the fatigue crack growth in these panels, using test results generated recently under the Composite Repair of Aircraft Structures (CRAS) program.
Influence of Carbon Content in Cobalt-Based Superalloys on Mechanical and Wear Properties
Authors: Liu Rong , Yao Matthew X. , Wu Xijia
Published: March 2004

Two cobalt-based superalloys containing 1.6% and 2% carbon respectively were studied, with the emphasis on the influence of the carbon content on their microstructures, wear resistance, and mechanical properties. Phase formation and transformation in the microstructures were analyzed using metallographic, X-ray diffraction, and differential scanning calorimetry techniques. Wear resistance, tensile and fatigue behaviors of the alloys were investigated on a pin-on-disc tribometer, MTS machine and rotating-bending machine, respectively. It is found that the wear resistance was increased significantly with the carbon content. The mechanical properties of the alloys are also influenced by the carbon content, but the impact is not so significant as on the wear resistance. It was observed that the carbon content increased the yielding strength and fatigue strength, but decreased the fracture stress and fracture strain.
Fatigue Crack Initiation Behavior of Welded AA5083 in a Seawater Environment
Authors: Benedictus-deVries Saskia , Bakker Ad , Janssen G. C. A. M. , de Wit Hans
Published: March 2004

Aluminum Alloy 5083 is increasingly used in the ship building industry due to its excellent corrosion resistance and its favorable mechanical properties. A significant application of this alloy is in high speed ferries, where the influence of dynamic loads is of great importance as well. However, the influence of a corrosive environment and/or a welded condition on the fatigue properties of nautical aluminum alloys has been studied only superficially. In the present paper the influence of a seawater environment in combination with a welded state is described. Both fatigue limits and SN-curves are given, as well as a fracture surface analysis. From these results the fracture and crack initiation mechanisms are explained. Particularly the penetration of seawater into sub-surface pores, that are present in the welded material, results in a significant drop in fatigue life time when the welded alloy is tested in seawater.