Anelastic Creep Phenomena in Thin Metal Plated Cantilevers for MEMS

2000 ◽  
Vol 657 ◽  
Author(s):  
Deborah J. Vickers-Kirby ◽  
Randall L. Kubena ◽  
Frederic P. Stratton ◽  
Richard J. Joyce ◽  
David T. Chang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Tunneling Current ◽  
Temperature History ◽  
Measured Temperature ◽  
Control Electrode ◽  
Turn On ◽  
The Past ◽  
History Of ◽  
Displacement Sensitivity ◽  
Vacuum Anneal

ABSTRACTDuring the past several years, we have developed high displacement sensitivity tunneling accelerometers using surface micromachining and metal electroplating techniques. These devices consist of a Au tunneling tip fabricated below a 1-2 μm thick metal cantilever beam of electroplated Ni or Au. A thin film of e-beam evaporated Au on the underside of the cantilever serves as the tunneling counter electrode. In operation, a 100mV bias is applied across the tunneling gap. A larger turn-on voltage is also applied between the cantilever and a control electrode, located on the substrate, to deflect the cantilever and maintain a constant tunneling current of 1 or 10 nA. Typical deflections of the end of 100 μm-long and 250 μm-long cantilevers are 0.5μm during operation. We have observed that the turn-on voltage decreases over time for most devices with a larger drop observed for the Au cantilevers. In all cases, the initial decay of the turn-on voltage was almost completely recoverable after the device was turned off for 24 hrs. This decay was not found to be strongly dependent on the magnitude of the tunneling current, but could be significantly reduced by pre-stressing the cantilever before operation. Finally, a vacuum anneal at 100°C influences the measured temperature dependence of the turn-on voltage. The observed effects appear to be consistent with fatigue and creep phenomena in the cantilevers. These effects are reversible at room temperature and are dependent on the stress and temperature history of the devices. A comparison is made between metal plated and all-Si structures.

CFD Simulation of Heating a Cu Pipe with a Safe H2/O2 Flame

2014 ◽  
Vol 611-612 ◽  
pp. 1553-1559
Author(s):  
Lars Kjäldman ◽  
Jouni Syrjänen
Keyword(s):  
Reasonable Agreement ◽  
Cfd Simulation ◽  
Temperature History ◽  
Measured Temperature ◽  
Dynamics Modeling ◽  
Computational Fluid Dynamics Modeling ◽  
History Of ◽  
Modeling And Experiments ◽  
Simulation Results ◽  
The Eu

As part of the EU/SME project SafeFlame (www.safeflameproject.eu ) the heating of a Cu pipe by a H2/O2 flame has been modeled and the results are compared to experiments. CFD (Computational Fluid Dynamics) modeling has been utilized to study the flow and combustion in the flame and the heat transfer from the flame to the pipe. The simulation results are compared with the measured temperature history of the pipe at different locations and with the visual flame. The influence of distance between the burner and the pipe and of using two opposite H2/O2 flames on the heating rate of the pipe has been investigated. Reasonable agreement between modeling and experiments has been obtained. The reasons for differences between modeling and experimental results are discussed.

scholarly journals The Natural History of “Inhibitors” to Factors VIII and IX in Hemophiliacs

1977 ◽  
Author(s):  
C.E.C. Harris
Keyword(s):  
Factor Viii ◽  
Room Temperature ◽  
Factor Ix ◽  
Standard Dosage ◽  
The Past ◽  
Frequent Administration ◽  
Life Threatening ◽  
History Of ◽  
Viii And Ix

Since 1954 an increasing number of adult hemophiliacs have been followed and “inhibitors” have been found in a minority of patients. A retrospective study was made of 9 factor-VIII and of 9 factor-IX cases who have attended with sufficient regularity for adequate documentation. The presence of this complication was, until recently, suspected because of failure clinically to respond to replacement therapy and confirmed by the original Biggs’ technique in the laboratory. In the past k years, this has been replaced by her method using serial dilutions at room temperature and at 37°C, incubated for 1 hour. In addition, studies have been made of factor recovery and survival following infusions.In no case were immuno-suppressive agents used. There were no deaths. Life-threatening crises were met by conservative measures, including hypothermia, and by the use of porcine factor-VIII. Instances when in vivo survival of infused concentrate was shortened were usually managed successfully by more frequent administration of equal or lesser dosage quantities; it was exceptional in such cases to witness enhancement of “inhibitor” potency as a consequence.In no less than 6 of the 9 patients would it seem that the “inhibitor” has disappeared and full clinical response is now being obtained with standard dosage schedules. The nature of “inhibitors” would not seem to be well understood.

scholarly journals Optimization Analysis of the Position of Thermometers Buried in Concrete Pouring Block Embedded with Cooling Pipes

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Yaoying Huang ◽  
Tong Xie ◽  
Chunguang Li ◽  
Xiaohui Yin
Keyword(s):  
Temperature Control ◽  
Optimization Algorithm ◽  
Arbitrary Point ◽  
Control Measures ◽  
Temperature History ◽  
Measured Temperature ◽  
Water Pipe ◽  
Average Temperature ◽  
History Of ◽  
Cooling Pipes

The measured temperature of a concrete pouring block depends strongly on the position of the buried thermometer. Only when the temperature measured by the thermometer accurately reflects the actual temperature of the concrete pouring block do reasonable temperature-control measures become possible. However, little research has been done on how to determine the proper position of thermometers buried in a concrete pouring block embedded with cooling pipes. To address this situation, we develop herein a method to determine the position of thermometers buried in a concrete pouring block. First, we assume that the design temperature-control process line characterizes the average-temperature history of the concrete pouring block. Under this assumption, we calculate the average-temperature history of the concrete pouring block by using the water-pipe-cooling FEM, following which the temperature history of an arbitrary point in the concrete pouring block is obtained by interpolating the shape function. Based on the average-temperature history of the concrete pouring block and the temperature history of the arbitrary point, we build a mathematical model to optimize the buried position of the thermometer and use the optimization algorithm to determine this position. By using this method, we establish finite-element models of concrete prisms with four typical water-pipe spacing cases for concrete-dam engineering and obtain the geometric position of the thermometers by using the optimization algorithm. By burying thermometers at these positions, the measured temperature should better characterize the average-temperature history of the concrete pouring block, which can provide useful information for regulating the temperature of concrete pouring blocks.

Response to Comment on “A 12-million-year temperature history of the tropical Pacific Ocean”

Science ◽  
2014 ◽  
Vol 346 (6216) ◽  
pp. 1467.2-1467 ◽  
Author(s):  
Yi Ge Zhang ◽  
Mark Pagani ◽  
Zhonghui Liu
Keyword(s):  
Warm Pool ◽  
Temperature Data ◽  
Temperature Gradients ◽  
Sea Surface ◽  
Temperature History ◽  
Tropical Pacific Ocean ◽  
The Past ◽  
Pacific Warm Pool ◽  
History Of ◽  
The Tropical Pacific

Contrary to our conclusions, Ravelo et al. argue that our TEX86-based sea surface temperature (SST) records do not conflict with the supposition of “permanent El Niño–like” conditions during the early Pliocene. We show that the way Ravelo et al. treat the existing temperature data perpetuates an inaccurate impression of cooler Pacific warm-pool SSTs and low equatorial temperature gradients in the past.

On The Possibility of an Autonomous History of Modern Southeast Asia

1961 ◽  
Vol 2 (2) ◽  
pp. 73-105 ◽  
Author(s):  
John R. W. Small
Keyword(s):  
Southeast Asia ◽  
Contemporary History ◽  
The Past ◽  
History Of

It is generally accepted that history is an element of culture and the historian a member of society, thus, in Croce's aphorism, that the only true history is contemporary history. It follows from this that when there occur great changes in the contemporary scene, there must also be great changes in historiography, that the vision not merely of the present but also of the past must change.

Stellar Evolution

1962 ◽  
Vol 11 (02) ◽  
pp. 137-143
Author(s):  
M. Schwarzschild
Keyword(s):  
Solar System ◽  
Stellar Evolution ◽  
Space Craft ◽  
New Techniques ◽  
Substantial Body ◽  
Individual Stars ◽  
The Past ◽  
Evolution Of Galaxies ◽  
History Of ◽  
Fast Flow

It is perhaps one of the most important characteristics of the past decade in astronomy that the evolution of some major classes of astronomical objects has become accessible to detailed research. The theory of the evolution of individual stars has developed into a substantial body of quantitative investigations. The evolution of galaxies, particularly of our own, has clearly become a subject for serious research. Even the history of the solar system, this close-by intriguing puzzle, may soon make the transition from being a subject of speculation to being a subject of detailed study in view of the fast flow of new data obtained with new techniques, including space-craft.

Granular bainite or granular ferrite? A preliminary TEM investigation of an HSLA-100 steel

1991 ◽  
Vol 49 ◽  
pp. 584-585
Author(s):  
R. Varughese ◽  
S. W. Thompson ◽  
P. R. Howell
Keyword(s):  
Room Temperature ◽  
Transformation Products ◽  
Accurate Description ◽  
Granular Bainite ◽  
Preliminary Results ◽  
The Past ◽  
Light Micrograph ◽  
Multiphase Reaction ◽  
Detailed Nature

Ever since Habraken and Economopoulos first employed the term granular bainite to classify certain unconventional transformation products in continuously cooled steels, the term has been widely accepted and used, despite the lack of a clear consensus as to the detailed nature of the transformation products which constitute granular bainite. This paper presents the preliminary results of a TEM investigation of an 0.04 wt% C, copper-containing steel (designated HSLA-100). It is suggested that the term granular ferrite rather than granular bainite is a more accurate description of this multiphase reaction product.Figure 1 is a light micrograph of a sample which had been air-cooled from 900°C to room temperature. The microstructure is typical of that which has been termed granular bainite in the past and appears to consist of equiaxed ferritic grains together with other minor transformation products. In order to examine these structures in more detail, both continuously cooled and isothermally transformed and quenched materials have been examined with TEM. Granular bainite has been found in virtually all samples.

A 200-Year History of the Study of Childhood Language Disorders of Unknown Origin: Changes in Terminology

2020 ◽  
Vol 5 (1) ◽  
pp. 6-11 ◽  
Author(s):  
Laurence B. Leonard
Keyword(s):  
Language Impairment ◽  
Specific Language Impairment ◽  
Scientific Literature ◽  
Language Disorder ◽  
Language Disorders ◽  
Unknown Origin ◽  
Developmental Language Disorder ◽  
The Past ◽  
History Of ◽  
The Many

Purpose The current “specific language impairment” and “developmental language disorder” discussion might lead to important changes in how we refer to children with language disorders of unknown origin. The field has seen other changes in terminology. This article reviews many of these changes. Method A literature review of previous clinical labels was conducted, and possible reasons for the changes in labels were identified. Results References to children with significant yet unexplained deficits in language ability have been part of the scientific literature since, at least, the early 1800s. Terms have changed from those with a neurological emphasis to those that do not imply a cause for the language disorder. Diagnostic criteria have become more explicit but have become, at certain points, too narrow to represent the wider range of children with language disorders of unknown origin. Conclusions The field was not well served by the many changes in terminology that have transpired in the past. A new label at this point must be accompanied by strong efforts to recruit its adoption by clinical speech-language pathologists and the general public.

Suicidal Ideation Among Medical Students in Dammam, Saudi Arabia

Crisis ◽  
2020 ◽  
pp. 1-6
Author(s):  
Mohammed Madadin ◽  
Ritesh G. Menezes ◽  
Maha A. Alassaf ◽  
Abdulaziz M. Almulhim ◽  
Mahdi S. Abumadini ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Medical Students ◽  
Suicidal Ideation ◽  
General Health Questionnaire ◽  
Cross Sectional Study ◽  
Eastern Province ◽  
Cross Sectional ◽  
The Past ◽  
Depression Subscale ◽  
History Of

Abstract. Background: Medical students are at high risk of suicidal ideation. Aim: We aimed to obtain information on suicidal ideation among medical students in Dammam located in the Eastern Province of Saudi Arabia. Method: This cross-sectional study was conducted at the College of Medicine affiliated with Imam Abdulrahman Bin Faisal University in the Eastern Province of Saudi Arabia. Suicidal ideation in the past 12 months was assessed based on responses to four questions in the depression subscale of the General Health Questionnaire 28 (GHQ-28). In addition, data were collected to examine the association of suicidal ideation with various factors. Results: We found that 1 in 3 medical students in the study had suicidal ideation in the past 12 months, while around 40% had lifetime suicidal ideation. Suicidal ideation was associated with feelings of parental neglect, history of physical abuse, and dissatisfaction with academic performance. Limitations: The cross-sectional nature of this study limits its ability to determine causality regarding suicidal ideation. Conclusion: These rates are considerably high when compared with rates from studies in other countries around the world. This study provides a reference in the field of suicidology for this region of Saudi Arabia.

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