Development, Characterisation and High-Temperature Suitability of Thin-Film Strain Gauges Directly Deposited with a New Sputter Coating System

New sensor and sensor manufacturing technologies are identified as a key factor for a successful digitalisation and are therefore economically important for manufacturers and industry. To address various requirements, a new sputter coating system has been invented at the Institute of Micro Production Technology. It enables the deposition of sensor systems directly onto technical surfaces. Compared to commercially available systems, it has no spatial limitations concerning the maximum coatable component size. Moreover, it enables a simultaneous structuring of deposited layers. Within this paper, characterisation techniques, results and challenges concerning directly deposited thin film strain gauges with the new sputter coating system are presented. Constantan (CuNiMn 54/45/1) and NiCr 80/20 are used as sensor materials. The initial resistance, temperature coefficient of resistance and gauge factor/k-factor of quarter-bridge strain gauges are characterised. The influence of a protective layer on sensor behaviour and layer adhesion is investigated as well. Moreover, the temperature compensation quality of directly deposited half-bridge strain gauges is evaluated, optimised with an external trimming technology and benchmarked against commercial strain gauges. Finally, the suitability for high-temperature strain measurement is investigated. Results show a maximum operation temperature of at least 400 °C, which is above the current state-of-the-art of commercial foil-based metal strain gauges.

Recent Developments of Magnetoresistive Sensors for Industrial Applications

The research and development in the field of magnetoresistive sensors has played an important role in the last few decades. Here, the authors give an introduction to the fundamentals of the anisotropic magnetoresistive (AMR) and the giant magnetoresistive (GMR) effect as well as an overview of various types of sensors in industrial applications. In addition, the authors present their recent work in this field, ranging from sensor systems fabricated on traditional substrate materials like silicon (Si), over new fabrication techniques for magnetoresistive sensors on flexible substrates for special applications, e.g., a flexible write head for component integrated data storage, micro-stamping of sensors on arbitrary surfaces or three dimensional sensing under extreme conditions (restricted mounting space in motor air gap, high temperatures during geothermal drilling).

Hornhautendothelzellzahl nach Augenmuskeloperationen an zwei und mehr geraden Augenmuskeln

BACKGROUND

The short-term impact of eye muscle surgery on the blood-aqueous barrier has been described by iris fluoresceinangiography and laser tyndallometry. The aim of this study was to investigate the long-term effects of eye muscle surgery on the oxygen supply of the anterior segment of the eye by determination of the corneal endothelial cell density.

PATIENTS AND METHODS

We investigated the corneal endothelial cell density of 32 patients with unilateral rectus muscle surgery pre- and postoperatively (24 cases of primary surgery on 2 horizontal muscles, 4 revision surgeries on 2 horizontal muscles, and 4 primary eye muscle surgeries on the 2 vertical recti including: 3 transpositions of the lateral halves of the vertical recti additional to recession of the medial rectus and one complete transposition of the two vertical recti). Exclusion criteria were previous intraocular surgery and retinal detachment surgery. Mean age at surgery was 37.5 +/- 16.3 (14.5 to 79.9) years. Mean follow-up time was 5.0 +/- 2.2 (1.9 to 10.1) months. The corneal endothelial cell density (CECD) was quantified by means of a specular microscope (EM-1000, Tomey).

RESULTS

The intraocular difference in CECD was not statistically significant either pre- or postoperatively. Mean values were 84 +/- 297 (731 to 700) vs. 52 +/- 357 (600 to 800), p = 0.64. In the subgroups of patients with revision surgery and those with primary eye muscle surgery involving the vertical recti, there was also no significant intraocular difference of CECD.

CONCLUSIONS

Based on the corneal endothelial cell density, there was no evidence of a chronically decreased oxygen supply of the anterior segment even after complex eye muscle surgery.

Testing two elements of spirituality in depressed and non-depressed elders

Depression is a common source of morbidity and mortality among elders in North America and has a significant impact on their quality of life. Meaning in life and self transcendence, indicators of spirituality, have been linked to the experience of well-being in the elderly. Nurses are challenged to find ways to tap these natural resources as a means of addressing the serious problem of depression in the aged. The purpose of this study was to compare patterns of depression, meaning in life and self-transcendence as measured in three instruments in a group of elders 75 years of age and older. The Geriatric Depression Scale, Purpose in Life Test and Self-Transcendence Scale were completed by 77 elders residing independently or semi-independently in one of three retirement communities. Significant negative relationships were found between depression and meaning in life, and between depression and self-transcendence. A significant positive relationship was found between meaning in life and self-transcendence. Demographic data further contributed to patterns of depression and well-being in this group. The study conclusions support the importance of meaning in life and self-transcendence for well-being in the elderly. Based on the study results, suggestions are offered about ways to enhance health and well-being in this cohort.

[Teleconsultation network for ophthalmology--experiences and results]

MOTIVATION

Telemedical services for ophthalmology are developed within the OPHTEL project, which has been funded by the European Union and by the Bavarian government in the Bavaria-online initiative.

METHODS

Seven private ophthalmologists, one university eye clinic, one clinical Diabetes center and an informatics research institute are connected within a teleconsultation network. Asynchronous (based on Internet E-Mail) and synchronous (based on ISDN-mediated videoconferencing tools) types of teleconsultations are realized.

RESULTS

86 teleconsultations (62 asynchronous, 23 synchronous) took place within the first 10 months. Complex and rare eye diseases as well as interdisciplinary questions (ophthalmology--diabetology) are the main area of medical communication interest. Legal and security problems are discussed.

CONCLUSIONS

Telemedical services must be understood as a complete process of medical care on the basis of modern communication technologies, which influences also the management of this process.

[Concentration of ampicillin in the vitreous after photocoagulation of the retina (author's transl)]

After photocoagulation of the retina a higher amount of ampicillin was found in the vitreous of the coagulated eyes, as our tests have shown. The reached concentrations of ampicillin were in the therapeutical region for sensitive germs. The highest concentration of ampicillin was reached when the ampicillin was injected in the edema stage of the coagulation effects. Therapeutical effective concentrations in the vitreous could be kept with this method up to five days after photocoagulation.

[Early alterations of the conjunctiva after alkali-burning (author's transl)]

Early alterations of the conjunctiva after alkaliburning (with 0.25 N NaOH) are described. After chemical damage, there is a nearly total loss of conjunctival epithelium, with simultaneous marked edema in the lower conjunctival parts. Alterations of the surface are examined by scanning electronic microscopy (SEM). Within 24 h marked infiltration of round cells into the conjunctival stroma takes place. After burning, we find a rapid decrease in the ATP level in the conjunctiva to about one-tenth of the normal value, whereas glucose and lactate showed only small alterations before and after chemical injury.