Long-term evaluation of scientific-echosounder performance

Abstract Knudsen, H. P. 2009. Long-term evaluation of scientific-echosounder performance. – ICES Journal of Marine Science, 66: 1335–1340. When scientific acoustic instruments are utilized for quantitative measurements of underwater biological resources, it is extremely important to know their overall performance, and it is imperative to measure their stability over time. Echosounders mounted on research vessels are therefore routinely calibrated several times annually, often immediately before, during, and after important resource-assessment surveys. In recent years, multifrequency systems for acoustic surveys requiring species identification and categorization based on the frequency response of targets have been introduced, further emphasizing the importance of monitoring instrument performance. In the 1970s, hydrophones and steel spheres were used as alternative references for calibrations. Substantial variations of system performance were observed, however, and gradually it was accepted that the use of hydrophones was inappropriate, because their performance varied more than that of the instruments being calibrated. Not until optimized reference targets were introduced in ca. 1980, was it possible to monitor the stability of acoustic-survey equipment with an acceptable degree of confidence. For the first time, the true, long-term stability of transducers, including ageing effects, could be accurately measured. This paper gives examples of calibration time-series for several Norwegian research vessels operating in various regions from Arctic to tropical waters.

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The Stability of the WHO Reference Thromboplastin NIBS & C 67/40

Thrombosis and Haemostasis ◽

10.1055/s-0038-1657008 ◽

1979 ◽

Vol 42 (04) ◽

pp. 1135-1140 ◽

Cited By ~ 9

Author(s):

G I C Ingram

Keyword(s):

Human Brain ◽

Collaborative Study ◽

Calibration Constant ◽

Long Term Stability ◽

Freeze Dried ◽

Show Evidence ◽

Human Material ◽

Reference Preparation ◽

The Stability

SummaryThe International Reference Preparation of human brain thromboplastin coded 67/40 has been thought to show evidence of instability. The evidence is discussed and is not thought to be strong; but it is suggested that it would be wise to replace 67/40 with a new preparation of human brain, both for this reason and because 67/40 is in a form (like Thrombotest) in which few workers seem to use human brain. A �plain� preparation would be more appropriate; and a freeze-dried sample of BCT is recommended as the successor preparation. The opportunity should be taken also to replace the corresponding ox and rabbit preparations. In the collaborative study which would be required it would then be desirable to test in parallel the three old and the three new preparations. The relative sensitivities of the old preparations could be compared with those found in earlier studies to obtain further evidence on the stability of 67/40; if stability were confirmed, the new preparations should be calibrated against it, but if not, the new human material should receive a calibration constant of 1.0 and the new ox and rabbit materials calibrated against that.The types of evidence available for monitoring the long-term stability of a thromboplastin are discussed.

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Structure-Properties Correlation of Cross-Linked Penicillin G Acylase Crystals

Crystals ◽

10.3390/cryst11040451 ◽

2021 ◽

Vol 11 (4) ◽

pp. 451

Author(s):

Marta Kubiak ◽

Janine Mayer ◽

Ingo Kampen ◽

Carsten Schilde ◽

Rebekka Biedendieck

Keyword(s):

Mechanical Stability ◽

Structural Characteristics ◽

Penicillin G ◽

Bacillus Species ◽

Diffusion Limitations ◽

Small Water ◽

Long Term Stability ◽

Atomic Force ◽

First Time

In biocatalytic processes, the use of free enzymes is often limited due to the lack of long-term stability and reusability. To counteract this, enzymes can be crystallized and then immobilized, generating cross-linked enzyme crystals (CLECs). As mechanical stability and activity of CLECs are crucial, different penicillin G acylases (PGAs) from Gram-positive organisms have proven to be promising candidates for industrial production of new semisynthetic antibiotics, which can be crystallized and cross-linked to characterize the resulting CLECs regarding their mechanical and catalytic properties. The greatest hardness and Young’s modulus determined by indentation with an atomic force microscope were observed for CLECs of Bacillus species FJAT-PGA CLECs (26 MPa/1450 MPa), followed by BmPGA (Priestia megaterium PGA, 23 MPa/1170 MPa) and BtPGA CLECs (Bacillus thermotolerans PGA, 11 MPa/614 MPa). In addition, FJAT- and BtPGA CLECs showed up to 20-fold higher volumetric activities compared to BmPGA CLECs. Correlation to structural characteristics indicated that a high solvent content and low number of cross-linking residues might lead to reduced stability. Furthermore, activity seems to be restricted by small water channels due to severe diffusion limitations. To the best of our knowledge, we show for the first time in this study that the entire process chain for the characterization of diverse industrially relevant enzymes can be performed at the microliter scale to discover the most important relationships and limitations.

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Limitations and Challenges in the Stability of Cysteamine Eye Drop Compounded Formulations

Pharmaceuticals ◽

10.3390/ph15010002 ◽

2021 ◽

Vol 15 (1) ◽

pp. 2

Author(s):

Cristina Martín-Sabroso ◽

Mario Alonso-González ◽

Ana Fernández-Carballido ◽

Juan Aparicio-Blanco ◽

Damián Córdoba-Díaz ◽

...

Keyword(s):

Shelf Life ◽

Stability Study ◽

Eye Drops ◽

Microbiological Analysis ◽

Nitrogen Gas ◽

Long Term Stability ◽

Main Degradation Product ◽

The Stability ◽

Unstable Molecule

Accumulation of cystine crystals in the cornea of patients suffering from cystinosis is considered pathognomonic and can lead to severe ocular complications. Cysteamine eye drop compounded formulations, commonly prepared by hospital pharmacy services, are meant to diminish the build-up of corneal cystine crystals. The objective of this work was to analyze whether the shelf life proposed for six formulations prepared following different protocols used in hospital pharmacies is adequate to guarantee the quality and efficacy of cysteamine eye drops. The long-term and in-use stabilities of these preparations were studied using different parameters: content of cysteamine and its main degradation product cystamine; appearance, color and odor; pH and viscosity; and microbiological analysis. The results obtained show that degradation of cysteamine was between 20% and 50% after one month of storage in the long-term stability study and between 35% and 60% in the in-use study. These data confirm that cysteamine is a very unstable molecule in aqueous solution, the presence of oxygen being the main degradation factor. Saturation with nitrogen gas of the solutions offers a means of reducing cysteamine degradation. Overall, all the formulae studied presented high instability at the end of their shelf life, suggesting that their clinical efficacy might be dramatically compromised.

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A SLR Pre-Processing Algorithm Based on Satellite Signature Effect

Applied Sciences ◽

10.3390/app11198880 ◽

2021 ◽

Vol 11 (19) ◽

pp. 8880

Author(s):

Bowen Guan ◽

Cunbo Fan ◽

Ning An ◽

Ricardo Cesar Podesta ◽

Dra Ana Pacheco ◽

...

Keyword(s):

Mean Value ◽

Observation Data ◽

Short Term ◽

Error Sources ◽

Effect Model ◽

The Mean ◽

The Stability ◽

First Time ◽

Satellite Signature Effect

As one of the major error sources, satellite signature effect should be reduced or even erased from the distribution of the post-fit residuals to improve the ranging precision. A simulation of satellite signature effect removal process for normal point algorithm is conducted based on a revised model of satellite response, which fully considers the structural and distribution characteristics of retroreflectors. In order to eliminate both long-term and short-term satellite signature effect, a clipping method for SLR data processing is proposed by defining the clipping location as 5.6 mm away from the mean value of the long-term fit residuals to select effective returns for normal points. The results indicate that, compared to normal points algorithm, the RMS per NP of LAGEOS-1 observation data processed by the clipping method is reduced from 62.90 ± 9.9 mm to 56.07 ± 4.69 mm, and the stability of RMS is improved 53%. This study improves the satellite signature effect model and simulates the fluctuation of normal points caused by satellite signature effect for the first time. The new method based on the simulation of satellite signature effect has stronger robustness and applicability, which can further minimize the influence of satellite signature effect on the SLR production and significantly improve the data property.

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Ectoparasites of the bats from karst caves of the nature reserve «Ichalkovsky Bor» (Nizhny Novgorod Region)

Samara Journal of Science ◽

10.17816/snv201874121 ◽

2018 ◽

Vol 7 (4) ◽

pp. 122-126

Author(s):

Galina Anatolievna Fadeeva ◽

Elena Evgenievna Boryakova

Keyword(s):

Natural Habitats ◽

Karst Caves ◽

Central Russia ◽

The Family ◽

Volga Upland ◽

The Stability ◽

The One ◽

Parasitic Mites ◽

First Time

The fauna of parasitic mites of bats from the karst caves in the region of the Volga Upland was studied in 2004-2005. Six species of bats such as Daubentons water bat, Brandts bat, whiskered bat, pond bat, northern bat and long-eared bat were examined. 18 species of arthropods were detected, among them there are gamasid mites (10 species) and harvest mites (2 species). Leptotrombidium russicum (Oud., 1902) and Myotrombicula sp. were found for the first time in Central Russia. Spinturnix acuminatus (Koch, 1836), Steatonyssus spinosus (Willmann, 1936), Steatonyssus periblepharus (Kolenati, 1858), Macronyssus flavus (Kolenati, 1856) turned out to be the main group of parasites in this study. As for the insects flies of the family Nycteribiidae and fleas of the family Ischnopsyllidae were found. The cluster analysis of ectoparasite fauna has showed that they are more or less evenly distributed among all members of mixed colonies of bats, while there is no violation of specificity in the choice of hosts. Low values of the Berger-Parker index marked a lack of competition between species, which indicates the stability of parasitic communities formed on bats in mixed colonies and in natural habitats. This fact indicates a complex relationship between the parasites in the community on the one hand, and long-term existence of the community on the other hand. This, in its turn, shows that in long-evolving communities competitive relationships between parasites are obliterated, which gives them stability. Herewith the bat colony is used as an integral whole, although some parasitic species prefer certain types of hosts.

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LONG-TERM STABILITY ANALYSIS OF ACOUSTIC ABSORBING BOUNDARY CONDITIONS

Mathematical Models and Methods in Applied Sciences ◽

10.1142/s0218202513500280 ◽

2013 ◽

Vol 23 (11) ◽

pp. 2129-2154 ◽

Cited By ~ 1

Author(s):

HÉLÈNE BARUCQ ◽

JULIEN DIAZ ◽

VÉRONIQUE DUPRAT

Keyword(s):

Stability Analysis ◽

Boundary Conditions ◽

Absorbing Boundary Conditions ◽

Computational Domain ◽

Acoustic Wave Equation ◽

Absorbing Boundary ◽

Term Stability ◽

Long Term Stability ◽

The Stability

This work deals with the stability analysis of a one-parameter family of Absorbing Boundary Conditions (ABC) that have been derived for the acoustic wave equation. We tackle the problem of long-term stability of the wave field both at the continuous and the numerical levels. We first define a function of energy and show that it is decreasing in time. Its discrete form is also decreasing under a Courant–Friedrichs–Lewy (CFL) condition that does not depend on the ABC. Moreover, the decay rate of the continuous energy can be determined: it is exponential if the computational domain is star-shaped and this property can be illustrated numerically.

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A Review of Preparation and Tribological Applications of Pickering Emulsion

Journal of Tribology ◽

10.1115/1.4052480 ◽

2021 ◽

pp. 1-27

Author(s):

Yichen Bao ◽

Kai Liu ◽

Quan Zheng ◽

Lulu Yao ◽

Yufu Xu

Keyword(s):

Pickering Emulsion ◽

Solid Particles ◽

Preparation Methods ◽

Factors Affecting ◽

Long Term Stability ◽

New Strategy ◽

New Type ◽

The Stability ◽

Near Future

Abstract Pickering emulsion is a new type of stable emulsion made by ultra-fine solid particles instead of traditional surfactants as stabilizers, which has received widespread attention in recent years. The preparation methods of stator-rotor homogenization, high-pressure homogenization, and ultrasonic emulsification were compared with others in this work. The main factors affecting the stability of Pickering emulsion are the surface humidity of the solid particles, the polarity of the oil phase, and the oil-water ratio. These factors could affect the nature of the solid particles, the preparation process of Pickering emulsion and the external environment. Consequently, the long-term stability of Pickering emulsion is still a challenge. The tribological investigations of Pickering emulsion were summarized, and the multifunctional Pickering emulsion shows superior prospects for tribological applications. Moreover, the latest development of Pickering emulsion offers a new strategy for smart lubrication in the near future.

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Stability of a Piezoresistive Ceramic Pressure Sensor Made With LTCC Technology

Additional Conferences (Device Packaging HiTEC HiTEN & CICMT) ◽

10.4071/cicmt-2012-wa45 ◽

2012 ◽

Vol 2012 (CICMT) ◽

pp. 000371-000376 ◽

Cited By ~ 1

Author(s):

Marina Santo Zarnik ◽

Darko Belavic

Keyword(s):

Pressure Sensor ◽

Fatigue Testing ◽

Low Pressure ◽

Fatigue Tests ◽

Point Of View ◽

Long Term Stability ◽

Pressure Cycling ◽

Key Characteristics ◽

The Stability

This paper discusses the stability of a piezoresistive, LTCC-based, pressure sensor that was designed for measurements in a low-pressure range below 100 mbar. The intrinsic stability of the sensor's offset was evaluated at a constant ambient temperature and different conditions regarding the atmospheric humidity. The sensors were also subjected to functional fatigue tests, which included a full-scale and an overload pressure cycling. The results of the fatigue testing revealed the vulnerability of the sensor's structure from the point of view of the long-term stability and the life-cycle. Nevertheless, the stability of the key characteristics of the prototype sensors was found to be satisfactory for accurate measurements in the low-pressure ranges.

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Fabrication of Boron Compensated Hydrogenated Amorphous Silicon Films with Significantly Improved Stability Using Plasma Enhanced Chemical Vapor Deposition Technique

MRS Proceedings ◽

10.1557/proc-377-45 ◽

1995 ◽

Vol 377 ◽

Author(s):

Mohan K. Bhan

Keyword(s):

Chemical Vapor ◽

Short Term ◽

Term Stability ◽

Long Term Stability ◽

Vapor Deposition Technique ◽

Improved Stability ◽

Donor Acceptor ◽

B Doping ◽

The Stability

ABSTRACTWe have systematically investigated the effects of addition of sub-ppm levels of boron on the stability of a-Si:H films and p-i-n devices, deposited by PE-CVD technique. The films thus produced with appropriate amounts of boron, show a significant improvement in stability, when soaked under both AM 1.5 (short-term) as well as 10×sun (long-term) illumination conditions. The opto-electronic properties of the films are quite respectable It is concluded that boron compensates the native impurities by forming donor-acceptor pairs, which reduces the “fast” defects and hence the initial degradation of the films. It is also speculated that boron may also be improving the short-term stability, by reducing the recombination of light generated electrons and holes, by converting D° into D+ states. The long-term stability appears to get affected by hydrogen dilution which seems to reduce the amount of “slow” defects. As a result of B doping of i-layer, the initial conversion efficiency of the devices decreases. It is presumed that our devices may contain an enhanced level of boron impurity, than expected, making them as worse material and to degrade less.

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Scribing Method for Carbon Perovskite Solar Modules

Energies ◽

10.3390/en13071589 ◽

2020 ◽

Vol 13 (7) ◽

pp. 1589 ◽

Cited By ~ 2

Author(s):

Simone M. P. Meroni ◽

Katherine E. A. Hooper ◽

Tom Dunlop ◽

Jenny A. Baker ◽

David Worsley ◽

...

Keyword(s):

Screen Printing ◽

Fill Factor ◽

Transparent Electrode ◽

Perovskite Solar Cell ◽

Metal Contacts ◽

Good Efficiency ◽

Long Term Stability ◽

First Time

The fully printable carbon triple-mesoscopic perovskite solar cell (C-PSC) has already demonstrated good efficiency and long-term stability, opening the possibility of lab-to-fab transition. Modules based on C-PSC architecture have been reported and, at present, are achieved through the accurate registration of each of the patterned layers using screen-printing. Modules based on this approach were reported with geometric fill factor (g-FF) as high as 70%. Another approach to create the interconnects, the so-called scribing method, was reported to achieve more than 90% g-FF for architectures based on evaporated metal contacts, i.e., without a carbon counter electrode. Here, for the first time, we adopt the scribing method to selectively remove materials within a C-PSC. This approach allowed a deep and selective scribe to open an aperture from the transparent electrode through all the layers, including the blocking layer, enabling a direct contact between the electrodes in the interconnects. In this work, a systematic study of the interconnection area between cells is discussed, showing the key role of the FTO/carbon contact. Furthermore, a module on 10 × 10 cm2 substrate with the optimised design showing efficiency over 10% is also demonstrated.

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