Failures of Lightning Air-Termination Rods Fixed by Spacers

2021 ◽  
Vol 12 (2(44)2021) ◽  
pp. 36-41
Author(s):  
Jaroslaw WIATER ◽  
Keyword(s):  
Laboratory Tests ◽  
Real Life ◽  
Separation Distance ◽  
Laboratory Conditions ◽  
Weak Points

Air-termination rods with height above 2,5 m must be fixed to objects by for example spacer bars to ensure proper separation distance. Commercially available spacer bars are suitable in laboratory conditions only. Real-life scenarios show weak points of this solution. Dirty or wet spacers do not fulfil proper isolation strength to ensure proper separation distance. This changes the km factor used to calculate the separation distance. The paper presents laboratory tests for clean spacers, wet spacers and a few real photos of damage caused by spacer bars.

scholarly journals On Realistically Attacking Tor with Website Fingerprinting

2016 ◽  
Vol 2016 (4) ◽  
pp. 21-36 ◽  
Author(s):  
Tao Wang ◽  
Ian Goldberg
Keyword(s):  
Background Noise ◽  
Laboratory Tests ◽  
Training Data ◽  
Web Traffic ◽  
Training Set ◽  
Data Set ◽  
Laboratory Conditions ◽  
Testing Data ◽  
In The Wild ◽  
New Algorithms

Abstract Website fingerprinting allows a local, passive observer monitoring a web-browsing client’s encrypted channel to determine her web activity. Previous attacks have shown that website fingerprinting could be a threat to anonymity networks such as Tor under laboratory conditions. However, there are significant differences between laboratory conditions and realistic conditions. First, in laboratory tests we collect the training data set together with the testing data set, so the training data set is fresh, but an attacker may not be able to maintain a fresh data set. Second, laboratory packet sequences correspond to a single page each, but for realistic packet sequences the split between pages is not obvious. Third, packet sequences may include background noise from other types of web traffic. These differences adversely affect website fingerprinting under realistic conditions. In this paper, we tackle these three problems to bridge the gap between laboratory and realistic conditions for website fingerprinting. We show that we can maintain a fresh training set with minimal resources. We demonstrate several classification-based techniques that allow us to split full packet sequences effectively into sequences corresponding to a single page each. We describe several new algorithms for tackling background noise. With our techniques, we are able to build the first website fingerprinting system that can operate directly on packet sequences collected in the wild.

Mechanism of Rubber Cracking

1946 ◽  
Vol 19 (2) ◽  
pp. 406-416 ◽  
Author(s):  
E. F. Powell ◽  
V. E. Gough
Keyword(s):  
Laboratory Tests ◽  
Surface Film ◽  
Factors Affecting ◽  
Laboratory Conditions ◽  
Service Conditions ◽  
Exposure Conditions

Abstract Rubber and rubberlike polymers, in common with other materials which deteriorate on exposure to oxidizing or similar agents, eventually crack under normal atmospheric service conditions. The present paper confines itself to the factors affecting the type and appearance of the cracking which eventually occurs when a surface film of a rubber object (particularly when stressed) hardens and deteriorates in strength from any cause whatsoever. The importance of an understanding of the effects of exposure conditions on the character of the cracking produced cannot be too highly emphasized. This is so even if interest is confined solely to simple tests on new protective paints on an acceptance basis rather than research into surface deterioration. It is probable that many protective agencies have been accepted or rejected for extensive production tests because the initial laboratory tests have either not been representative of service or have been inadequate in scope. This still remains a major problem. The theory presented here has gradually taken shape over a period of some ten years and appears to describe adequately the general findings on the whole gamut of cracking, viz., fine check cracking and isolated deep cracks produced under service and laboratory conditions, the latter covering flexing, roof exposure, ozone and similar tests.

scholarly journals Assessment of Skid Resistance of Asphalt Mixtures in Laboratory Conditions

2012 ◽  
Vol 58 (4) ◽  
pp. 521-534 ◽  
Author(s):  
W. Gardziejczyk ◽  
M. Wasilewska
Keyword(s):  
Asphalt Concrete ◽  
Laboratory Tests ◽  
Asphalt Mixtures ◽  
Road Surface ◽  
Skid Resistance ◽  
Mastic Asphalt ◽  
Laboratory Conditions ◽  
University Of Technology ◽  
Road Surfaces ◽  
Stone Mastic Asphalt

AbstractThe aggregate applied for the wearing course has a significant influence on skid resistance of road surfaces. However, it is difficult to evaluate the behaviour of road surface in use on the basis of the Polished Stone Value (PSV) determined for the aggregate according to the so called ‘British method’. The British method, which is currently used in many countries, does not allow to determine the influence of neither the grain size of the aggregate nor the type of the wearing course on skid resistance of road surface. The present paper suggests a method for evaluation of the British Pendulum Number (BPN) for road surfaces in laboratory conditions. The authors assumed the BPN for polished slabs, made from asphalt mixtures, as the criterion. The index was measured with the British Pendulum Tester. The simulation of the process was conducted on research stand (called slab polisher) built at Bialystok University of Technology (BUT). The results of laboratory tests indicate that surfaces from asphalt concrete (AC) have slightly higher values of BPN in comparison with the values determined for surfaces made from stone mastic asphalt (SMA).

scholarly journals Thermal And Optical Performance Of Granular Aerogel Glazing After Accelerated Ageing

2021 ◽  
Author(s):  
VAdim Novik
Keyword(s):  
Real Life ◽  
New Product ◽  
Climatic Conditions ◽  
Temperature Cycling ◽  
Accelerated Ageing ◽  
Optical Performance ◽  
Maximum Reduction ◽  
Visible Transmittance ◽  
Weak Points ◽  
U Value

The glazing portion of a window has dual but conflicting functions where it is required to provide views to the outside, but also have good thermal resistance. Glazing is usually one of the weak points in the thermal envelope and tends to age quicker and to a higher severity. The combination of granular aerogel inside a glazing cavity is still relatively new product, but could offer both great thermal and optical performance. Currently available durability data for granular aerogel glazing is scarce. Accelerated ageing was used to generate real life equivalent stresses of 13.5‐74 years by exposing a set of samples to several climatic conditions. The center of glass U‐value increased by a maximum of 4% after accelerated ageing in the oven and the temperature cycling machine. A maximum reduction of 211% was measured in the visible transmittance after accelerated ageing climatic and humidity chambers.

Artificial neural networks in diagnosis of thyroid function from in vitro laboratory tests

1993 ◽  
Vol 39 (11) ◽  
pp. 2248-2253 ◽  
Author(s):  
P K Sharpe ◽  
H E Solberg ◽  
K Rootwelt ◽  
M Yearworth
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Thyroid Function ◽  
Laboratory Tests ◽  
Extreme Values ◽  
Real Life ◽  
Training Data ◽  
Data Set ◽  
Artificial Neural

Abstract We studied the potential benefit of using artificial neural networks (ANNs) for the diagnosis of thyroid function. We examined two types of ANN architecture and assessed their robustness in the face of diagnostic noise. The thyroid function data we used had previously been studied by multivariate statistical methods and a variety of pattern-recognition techniques. The total data set comprised 392 cases that had been classified according to both thyroid function and 19 clinical categories. All cases had a complete set of results of six laboratory tests (total thyroxine, free thyroxine, triiodothyronine, triiodothyronine uptake test, thyrotropin, and thyroxine-binding globulin). This data set was divided into subsets used for training the networks and for testing their performance; the test subsets contained various proportions of cases with diagnostic noise to mimic real-life diagnostic situations. The networks studied were a multilayer perceptron trained by back-propagation, and a learning vector quantization network. The training data subsets were selected according to two strategies: either training data based on cases with extreme values for the laboratory tests with randomly selected nonextreme cases added, or training cases from very pure functional groups. Both network architectures were efficient irrespective of the type of training data. The correct allocation of cases in test data subsets was 96.4-99.7% when extreme values were used for training and 92.7-98.8% when only pure cases were used.

Figure 1. Anmonia-binding capacity of the three litters under laboratory conditions. 4. LIQUID-BINDING CAPACITY The absorption capacity of the litter determines the amount used, and also affects the functioning of hydraulic manure presses. Hie absorption capacity of litter depends on its initial moisture content. In the laboratory tests , peat had a much greater absorption capacity than other litters. Peat absorbed a maximum of 4.5 times its own weight of liquid, straw 3.5 times, cutter shavings 3.6 times and sawdust 1.5 times (4). The litters used in the tests had an initial moisture content of 20%, with the exception of peat, which contained 40% moisture. These moisture contents represent the working values for good-quality litters. Peat was far superior in terms of absoption capacity to the other litters. Litter should retain its absorption capacity even when under pressure, for example in a hydraulic manure press. The ability of litters to withstand pressure was tested by first allowing than to absorb either water or urine. The litters were then compressed in a hydraulic press for one hour as the pressure was increased stepwise from 20 N/an2 to 50 N/an2. The pressure exerted by hydraulic manure presses in practice is around 40-60 N/cm2. All the retained urine better than water. Sawdust was found to have the greatest resistance to pressure, retaining about 75% of the absorbed

1986 ◽  
pp. 197-197
Keyword(s):  
Moisture Content ◽  
Laboratory Tests ◽  
Binding Capacity ◽  
Initial Moisture Content ◽  
Hydraulic Press ◽  
Absorption Capacity ◽  
The Other ◽  
Moisture Contents ◽  
Laboratory Conditions ◽  
Better Than

scholarly journals Identification of Foliar Salt Tolerance of Woody Perennials Using Chlorophyll Fluorescence

HortScience ◽  
2005 ◽  
Vol 40 (6) ◽  
pp. 1892-1897 ◽  
Author(s):  
G.C. Percival
Keyword(s):  
Chlorophyll Fluorescence ◽  
Salt Tolerance ◽  
Laboratory Tests ◽  
Woody Perennials ◽  
Laboratory Conditions ◽  
Whole Plant ◽  
Leaf Necrosis ◽  
Plant Salt Tolerance ◽  
Whole Plants ◽  
Inexpensive Procedure

Aims of this investigation were to determine whether chlorophyll fluorescence values obtained from excised leaves of woody perennials subjected to salinity stress under laboratory conditions provided a measurable indicator of whole plant salinity tolerance. Laboratory tests consisted of measurements of the ratio of variable to maximal chlorophyll fluorescence (Fv/Fm) performed on excised leaves taken from thirty woody perennials following immersion in salt solutions ranging from concentrations of 2% to 7%. Based on reductions in Fv/Fm of excised leaves following salinity treatments plants were ranked in order of tolerance. Whole plants of six of the thirty species tested were then subjected to a foliar applied salt at a concentration of 7% and placed under glass for 14 weeks. Damage to, and recovery of whole plants from salt damage as measured by chlorophyll fluorescence, leaf necrosis and chlorophyll content mirrored tolerance ranking of excised leaves under laboratory conditions. In addition, based on reductions in plant growth at the cessation of the experiment, salt tolerance followed a similar order as that obtained from Fv/Fm values of excised leaves. Results indicate that testing of excised leaf material of woody perennials under laboratory conditions using chlorophyll fluorescence offers a potentially quick, reliable and inexpensive procedure that can provide a useful means of estimating whole plant salt tolerance.

scholarly journals Evaluating the Efficacy of the Supertowel™ as a Handwashing Product: A Simulation of Real-World Use Conditions

2021 ◽  
Author(s):  
Belen Torondel ◽  
Rummana Khan ◽  
Torben Holm Larsen ◽  
Sian White
Keyword(s):  
Escherichia Coli ◽  
Real World ◽  
Laboratory Tests ◽  
Crossover Design ◽  
The Other ◽  
Reference Condition ◽  
Contaminated Water ◽  
Emergency Situations ◽  
Laboratory Conditions ◽  
Handwashing With Soap

The Supertowel is a fabric treated with a permanent antimicrobial bonding and has been designed as a soap alternative in emergency situations. The Supertowel has been shown to be as efficacious as handwashing with soap and water when tested under controlled laboratory conditions. It has also been shown to be a practical, acceptable, and desirable product among crisis-affected populations. The aim of this study was to test whether the Supertowel remains as efficacious when used under conditions which mimic real-world hand cleaning in challenging settings. Two rounds of laboratory tests, with 16 volunteers in each, were conducted to test the efficacy of the Supertowel when used for a shorter duration, when less wet, when used with contaminated water, when visibly dirty, and when dry. Volunteers pre-contaminated their hands with nonpathogenic Escherichia coli. Comparisons were made between hand cleaning with the Supertowel and the reference condition (normally handwashing with soap), using a crossover design. The Supertowel was marginally less efficacious than handwashing with soap when used for 15 seconds (P = 0.04) but as efficacious at 30 and 60 seconds durations. All the other Supertowel conditions were as efficient as their reference comparisons meaning that the Supertowel can effectively remove pathogens from hands when it is wet, damp, or completely dry, when it is used with contaminated water, when visibly dirty with mud and/or oil.

INTERACTION OF TWO DIFFERENTLY SIZED BUBBLES IN A FREE FIELD

2012 ◽  
Vol 19 ◽  
pp. 180-184
Author(s):  
LUP WAI CHEW ◽  
BOO CHEONG KHOO ◽  
EVERT KLASEBOER ◽  
SIEW-WAN OHL
Keyword(s):  
High Speed ◽  
Free Field ◽  
Real Life ◽  
Separation Distance ◽  
Liquid Jets ◽  
Size Difference ◽  
High Speed Photography ◽  
Distinct Region ◽  
Bubble Interactions ◽  
Multiple Bubbles

The interaction between two different sized (spark created, non-equilibrium) bubbles is studied by using high speed photography. The bubble size ranges from 2 to 7 mm. The experimental results are compared to that of the similar sized bubbles reported in the literature. Interestingly, all the four major behaviors of bubble-bubble interactions (i.e. 'bubble-collapsed' induced liquid jets directed away from each other, liquid jets directed towards each other, bubble coalescence and the 'catapult' effect) are observed which bear much similarity to that found for similar sized bubbles' interaction. The main parameters studied/varied are the size of the bubbles, the dimensionless separation distance and the phase difference between the two bubbles. The results obtained are consistent with the cases of similar sized bubbles reported in the literature, with each type of behavior occupying a distinct region in the graphical plot. This indicates that the results for the (special) similar sized bubbles can be generalized to cases with different sized bubbles. Many of the real life applications such as cavitations corrosions often involve bubbles with significant size difference, thus the present findings are useful in predicting the behavior of multiple bubbles in many situations.

Common Sound Scenarios: A Context-Driven Categorization of Everyday Sound Environments for Application in Hearing-Device Research

2016 ◽  
Vol 27 (07) ◽  
pp. 527-540 ◽  
Author(s):  
Florian Wolters ◽  
Karolina Smeds ◽  
Erik Schmidt ◽  
Eva Kümmel Christensen ◽  
Christian Norup
Keyword(s):  
Signal Processing ◽  
Laboratory Tests ◽  
Western Europe ◽  
Literature Search ◽  
Real Life ◽  
Field Trials ◽  
Normal Hearing ◽  
Speech Communication ◽  
Hearing Device ◽  
Acoustic Environments

Background: Evaluation of hearing-device signal-processing features is performed for research and development purposes, but also in clinical settings. Most people agree that the benefit experienced in a hearing-device user’s daily life is most important, but laboratory tests are popular since they can be performed uniformly for all participants in a study using sensitive outcome measures. In order to design laboratory tests that have the potential of indicating real-life benefit, there is a need for more information about the acoustic environments and listening situations encountered by hearing-device users as well as by normal-hearing people. Purpose: To investigate the acoustic environments and listening situations people encounter, and to provide a structured framework of common sound scenarios (CoSS) that can be used for instance when designing realistic laboratory tests. Research Design: A literature search was conducted. Extracted acoustic environments and listening situations were categorized using a context-based approach. A set of common sound scenarios was established based on the findings from the literature. Data Collection: A number of publications providing data on encountered acoustic environments and listening situations were identified. Focus was on studies including informants who reported or recorded information in field trials. Nine relevant references were found. In combination with data collected at our laboratory, 187 examples of acoustic environments or listening situations were found. Results: Based on the extracted data, a categorization approach based on context (intentions and tasks) was used when creating CoSS. Three intention categories, “speech communication,” “focused listening,” and “nonspecific” were divided into seven task categories. In each task category, two sound scenarios were described, creating in total 14 common sound scenarios. The literature search showed a general lack of studies investigating acoustic environments and listening situations, in particular studies where normal-hearing informants are included and studies performed outside North America and Western Europe. Conclusions: A structured framework was developed. Intentions and tasks constitute the main categories in the framework, and 14 common sound scenarios were selected and described. The framework can for instance be used when developing hearing-device signal-processing features, in the evaluation of such features in realistic laboratory tests, and for demonstration of feature effects to hearing-device wearers.

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