Experimental Study on Wear and Fracture in Aeronautical Gear Transmissions

2006 ◽  
Author(s):  
Roberto Bassani ◽  
Enrico Ciulli ◽  
Enrico Manfredi ◽  
Salvatore Manconi ◽  
Alessandro Polacco ◽  
...  
Keyword(s):  
High Performance ◽  
Surface Damage ◽  
Surface Finishing ◽  
Production Engineering ◽  
Damage Prediction ◽  
Gear Teeth ◽  
Qualitative And Quantitative ◽  
Computer Controlled ◽  
Quantitative Changes

This work presents some of the results obtained from an extensive experimental test campaign performed at the Department of Mechanical Nuclear and Production Engineering (DIMNP) of Pisa University with the partnership of Avio Propulsione Aerospaziale S.p.A. This test campaign, that is still being performed, is concerned with the characterization of teeth damage in high performance gear transmissions, such as aeronautical ones, characterized by high levels of velocity and load. Damage detection and monitoring have been pursued during all the tests in order to achieve a better understanding of causes and evolution of teeth damage. Moreover, to investigate the effects of different parameters on teeth damage, tests with different load, velocity, teeth geometry, materials and surface finishing, have been performed. The surface conditions of the gear teeth have been investigated using in particular two different instruments: a computer-controlled stylus profilometer able to perform 3D investigations and a scanning electron microscope (SEM) recently provided by a software for surface reconstruction. Qualitative and quantitative changes in surface roughness have been detected. Besides the experimental activity, numerical analyses have been also started for finding theoretical criteria for surface damage prediction; some few obtained results are presented. Due to the vastness of the work performed, only a survey of the main results obtained till now is presented in the paper.

Reliability Characterization of a Piezoelectric Actuator Based AVC System

2010 ◽  
Author(s):  
Marco Mazzola ◽  
Francesco Aggogeri ◽  
Angelo Merlo ◽  
Bernhard Brunner ◽  
Maria de la O Rodriguez
Keyword(s):  
Life Cycle ◽  
Life Cycle Cost ◽  
High Performance ◽  
Active Vibration Control ◽  
Control Device ◽  
Surface Finishing ◽  
Shape Error ◽  
Reliability Characteristics ◽  
Active Vibration

Reliability and Maintainability analyses are becoming an increasing competitive advantage in machine tool design. In particular, the goal of machine tools for Ultra High Precision Machining is to guarantee high specified performances and to maintain them over life cycle time. A structured reliability approach applied to such complex and innovative systems must be integrated in the early phase of the design. In this paper, the reliability characterization of an adjustable platform for micromilling operations is presented. The platform is intended to improve the surface finishing of the workpiece, through a broadband Active Vibration Control device based on high performance piezoelectric multilayer actuators. The study intends to assess the capability of the system to maintain along the life cycle the appropriate reduction of the chattering vibrations without any shape error. By dividing the system through a morphological-functional decomposition, the critical elements are detected and their reliability issues are extensively discussed. Their lifetimes are described through opportune distributions and models. The study is completed by the quantitative reliability prediction of the overall system. Finally, a sensitivity analysis is performed and reliability allocation implications are evaluated to determine the effect of every component on the system reliability characteristics and life cycle cost.

scholarly journals Observations on Altered Hepatocellular Foci in National Toxicology Program Two-Year Carcinogenicity Studies in Rats

1989 ◽  
Vol 17 (4_part_1) ◽  
pp. 690-708 ◽  
Author(s):  
Takanori Harada ◽  
Robert R. Maronpot ◽  
Richard W. Morris ◽  
Gary A. Boorman
Keyword(s):  
Liver Tumor ◽  
Morphological Variability ◽  
Mixed Cell ◽  
Qualitative And Quantitative ◽  
Fischer 344 ◽  
National Toxicology Program ◽  
Hepatic Neoplasia ◽  
Quantitative Changes ◽  
F344 Rats

Retrospective characterization of morphological and stereological features of altered hepatocellular foci (AHF) in hematoxylin & eosin (H&E)-stained sections was performed on 6 conventional 2−yr carcinogenicity studies conducted in Fischer 344 (F344) rats by the National Toxicology Program (NTP). In 3 of these studies where there was clear evidence of hepatocarcinogenicity [1−amino−2,4−dibromoanthraquinone (ADBAQ), C.I. Acid Red 114, methyl carbamate], there was greater morphological variability in AHF than in the studies of chemicals that were not hepatocarcinogenic [4−hydroxyacetanilide, epinephrine, dimethoxane]. In addition to having the expected types of AHF, rats treated with ADBAQ, C.I. Acid Red 114, and methyl carbamate had atypical basophilic AHF. In addition, atypical eosinophilic AHF were present in rats treated with ADBAQ. Both types of atypical AHF showed a morphological spectrum and sequential changes suggesting they could develop into hepatocellular neoplasms. For the 3 liver tumor positive studies, there were dose-and time-dependent increases in stereological parameters for the atypical as well as commonly occurring clear, vacuolated, and mixed cell AHF. Consistent stereological changes were not found for commonly occurring basophilic and eosinophilic AHF. Aside from some decreases in stereological measurements in some rats treated with 4−hydroxyacetanilide and epinephrine, there were no significant quantitative changes in AHF in the three liver tumor negative studies. These results show that hepatocarcinogens may induce unique types of AHF in conventional 2−yr carcinogenicity/toxicity studies in rats and may cause quantitative increases in commonly occurring clear, vacuolated, and mixed cell AHF. Such qualitative and quantitative changes are potentially useful predictors of hepatic neoplasia.

scholarly journals Ultra-high performance liquid chromatography-MS/MS (UHPLC-MS/MS) in practice: analysis of drugs and pharmaceutical formulations

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Ravsaheb H. Rathod ◽  
Suraj R. Chaudhari ◽  
Amod S. Patil ◽  
Atul A. Shirkhedkar
Keyword(s):  
High Performance ◽  
Pharmaceutical Formulations ◽  
Future Trend ◽  
Review Article ◽  
Main Body ◽  
Quantitative Investigation ◽  
Qualitative And Quantitative ◽  
Research Facilities ◽  
Safety Limit

Abstract Background UHPLC-MS/MS is connected in various research facilities for the qualitative and quantitative investigation of a pharmaceutical substance, pharmaceutical items, and biological specimen. Main body The commence review article is an endeavor to offer pervasive awareness around assorted aspects and details about the UHPLC-MS/MS and related techniques with the aim on practice to an estimation of medicinal active agents in the last 10 years. The article also focused on isolation, separation, and characterization of present impurity in drug and biological samples. Conclusion Review article compiles a general overview of medicinally important drugs and their analysis with UHPLC-MS/MS. It gives fundamental thought regarding applications of UHPLC-MS/MS for the study on safety limit. The summary of developed UHPLC-MS/MS methods gives a contribution to the future trend and limitations in this area of research.

scholarly journals Synthesis and Characterization of Sintered Magnetic Abrasives Used in Advance Finishing Processes Through Powder Metallurgy Route

2020 ◽  
Vol 5 (3) ◽  
pp. 27-33
Author(s):  
Ankit Bansal ◽  
◽  
Ravi Butola ◽  
M S Niranjan ◽  
Qasim Murtaza ◽  
...  
Keyword(s):  
High Performance ◽  
Surface Finishing ◽  
Future Research ◽  
Finishing Process ◽  
Tube Furnaces ◽  
Future Research Directions ◽  
Finishing Processes ◽  
Performance Surface ◽  
Magnetic Abrasives

The magnetic field-assisted surface finishing process needs a sintered magnetic abrasive powder which could be a mixture of SiC and CIP particles. Tube furnaces have been used to develop SiC-based sintered magnetic abrasives. The focus of this article is to investigate the anticipated results and to carry out the fabrication setup of sintered magnetic abrasive for the super-finishing of composite materials and their coating. The article depicts a significant effect on the mechanical properties such as microhardness and compressive strength and analyzes SiC and CIP composite-based microstructure. The synthesis of the powder involves four major processes like blending; compaction and sintering. Characterization of sintered magnetic abrasives has been done using SEM, EDS, XRD to study morphology, chemical composition, crystallography, and magnetic properties. The results have been compared with the un-bonded magnetic abrasives. This paper also presents a brief literature review of the state-of-the-art technology of high-performance surface finishing processes used in manufacturing industries. Finally, the downside and stray aspects of the related literature are spotlighted and a list of prospective issues for future research directions is recommended.

scholarly journals Characterization of Virginia Tobaccos by Chemometric Methods

2002 ◽  
Vol 20 (1) ◽  
pp. 1-6
Author(s):  
E Apostolova ◽  
S Dagnon ◽  
A Edreva
Keyword(s):  
Essential Oils ◽  
Sensory Evaluation ◽  
High Performance ◽  
Objective Evaluation ◽  
Pattern Recognition Method ◽  
Chemometric Methods ◽  
Recognition Method ◽  
Qualitative And Quantitative ◽  
Hplc Profiles

AbstractLeaf samples of different flue-cured Virginia tobacco varieties were analyzed and compared to a standard, the typical American Virginia cultivar K 326. Plants were grown in the Plovdiv region, Bulgaria, under conditions appropriate for Virginia varieties. The tobaccos were characterized by means of high performance liquid chromatography (HPLC) of polyphenols and capillary gas chromatography (CGC) of the neutral volatiles of essential oils, as well as by a sensory evaluation of color and aroma. All cultivars examined contained twelve polyphenol components in their HPLC profiles and differed only in quantitative aspects. Both qualitative and quantitative variations between the CGC profiles of essential oils of the cultivars were observed. The chromatographic profiles of polyphenols and essential oils were compared by the pattern recognition method (PRM) and used for calculating the similarity indexes (Is,%) of the samples to the standard Virginia variety K 326. The chemometric data obtained are completely compatible with sensory evaluation of color and aroma. Based on the results obtained the tobaccos may be distinguished as: typical full-flavored Virginia - aromatic (Virginia 330); typical full-flavored Virginia - less aromatic (Virginia 0454); non-typical (filler type) Virginia (Virginia 42). The possibilities of the PRM for objective evaluation of color and aroma of Virginia tobaccos were demonstrated.

Expression of laminin and beta-1 integrin in embryonic, neonatal, and adult rat heart

1991 ◽  
Vol 49 ◽  
pp. 182-183
Author(s):  
R.L. Price ◽  
T.K. Borg ◽  
L. Terracio ◽  
M. Nakagawa
Keyword(s):  
Temporal Expression ◽  
Qualitative And Quantitative ◽  
Adult Rat ◽  
Cytoplasmic Face ◽  
Extracellular Matrix Components ◽  
Basement Membrane Component ◽  
Beta 1 Integrin ◽  
Quantitative Changes ◽  
Cytoskeletal Elements ◽  
External Face

Little is known about the temporal expression of extracellular matrix components (ECM) and its receptors during development of the heart. Recent reports have shown that ECM components undergo both qualitative and quantitative changes during development, and it is believed that ECM components are important in the regulation of cell migration and cell:cell and cell:ECM recognition and adhesion.Integrins are transmembrane glycoproteins which bind several ECM components on their external face and cytoskeletal elements on the cytoplasmic face. Laminin is a basement membrane component which has been recognized as an important site for cell adhesion. Both the integrins and laminin are expressed early in development and continue to be expressed in the adult heart. With their documented roles in cell recognition, and cell:cell and cell:ECM migration and adhesion these proteins appear to be important components in development of the heart, and their temporal expression may play a pivotal role in morphogenesis and myofibrillogenesis of the heart.

Preparation and Characterization of NH2-Terminal Fibrinogen Bβ Fragments from N-DSK of Human Fibrinogen

1984 ◽  
Vol 51 (01) ◽  
pp. 016-021 ◽  
Author(s):  
S Birken ◽  
G Agosto ◽  
B Lahiri ◽  
R Canfield
Keyword(s):  
High Performance ◽  
Gel Filtration ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Reverse Phase ◽  
Human Fibrinogen ◽  
Human Volunteers ◽  
Cnbr Cleavage ◽  
Two Peaks

SummaryIn order to investigate the early release of NH2-terminal plasmic fragments from the Bβ chain of fibrinogen, substantial quantities of Bβ 1-42 and Bβ 1-21 are required as immunogens, as radioimmunoassay standards and for infusion into human volunteers to determine the half-lives of these peptides. Towards this end methods that employ selective proteolytic cleavage of these fragments from fibrinogen have been developed. Both the N-DSK fragment, produced by CNBr cleavage of fibrinogen, and Bβ 1-118 were employed as substrates for plasmin with the finding of higher yields from N-DSK. Bβ 1-42 and Bβ 1-21 were purified by gel filtration and ion-exchange chromatography on SP-Sephadex using volatile buffers. When the purified preparation of Bβ 1-42 was chromatographed on reverse-phase high performance liquid chromatography, two peaks of identical amino acid composition were separated, presumably due either to pyroglutamate or to amide differences.

Functional MR Imaging of the Motor Cortex in Active and Passive Movement: Qualitative and Quantitative Changes

2002 ◽  
Vol 46 (5) ◽  
pp. 425
Author(s):  
Ki Bong Yu ◽  
Myung Kwan Lim ◽  
Hyung Jin Kim ◽  
Jun Soo Byun ◽  
Young Kook Cho ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Mr Imaging ◽  
Passive Movement ◽  
Qualitative And Quantitative ◽  
Functional Mr Imaging ◽  
Quantitative Changes
Sign in / Sign up

Export Citation Format

Share Document