scholarly journals NUMERICAL SIMULATION MODELLING OF TEMPERATURE DISTRIBUTION IN THE PROCESS OF COAL SELF-HEATING IN THE MINED-OUT SPACES

2021 ◽  
Vol 2 (446) ◽  
pp. 167-173
Author(s):  
N. M. Suleimenov ◽  
Sh. K. Shapalov ◽  
G. S. Sattarova ◽  
В. О. Sapargaliyeva ◽  
S. B. Imanbayeva ◽  
...  
Keyword(s):  
Fire Hazard ◽  
Arbitrary Point ◽  
Field Measurements ◽  
Simulation Modelling ◽  
Emergency Situations ◽  
Self Heating ◽  
Individual Indicator ◽  
Underground Method ◽  
Thermodynamic Processes

Researches of thermodynamic processes of oxidation, self-heating and self-ignition of coal are necessary for studying of dependence of terminal parameters on a set of the influencing factors. In practice of coal mining by the underground method cases of coal self-ignition in the mined-out spaces of production units (lavas) are frequent. In this case one of the tasks consists in determination of temperature in arbitrary point of the nubbly-porous medium of the mined-out space. Need of the solution of this difficult task is caused by the probability of emergency situations in places with the explosive concentration of methane. It is possible that for each seam and grade of coal it is necessary to develop, substantiate and accept an individual indicator for assessing the state of fire hazard. It is proposed to systematize and methodically process the results of field measurements and observations on the analyzed and investigated cases of endogenous fires in problem areas of mines in order to create basin databases for subse- quent operational decisions in emergency situations.

scholarly journals Gas Chromatographic Determination of Fatty Acids in Oils with Regard to the Assessment of Fire Hazard

2017 ◽  
Vol 25 (40) ◽  
pp. 73-81 ◽  
Author(s):  
Alica Bartošová ◽  
Tomáš Štefko
Keyword(s):  
Fatty Acids ◽  
Double Bond ◽  
Spontaneous Combustion ◽  
Unsaturated Fatty Acids ◽  
Fire Hazard ◽  
Accurate Determination ◽  
Coconut Oil ◽  
Double Bonds ◽  
Self Heating

Abstract The aim of the paper was to study and research the application of processing gas chromatographic method for the rapid and accurate determination of the composition of different types of oils, such as substances with the possibility of an adverse event spontaneous combustion or self-heating. Tendency to spontaneous combustion is chemically characterized mainly by the amount of unsaturated fatty acids, which have one or more double bonds in their molecule. Vegetable oils essentially consist of the following fatty acids: palmitic, stearic, oleic, linoleic, and linoleic. For the needs of assessment, the fire hazard must be known, in which the double bond is present, as well as their number in a molecule. As an analytical method, GCMS was used for determination of oils content. Three types of oil were used - rapeseed, sunflower, and coconut oil. Owing to the occurrence of linoleic acid C18:2 (49.8 wt.%) and oleic acid C18:1 (43.3 wt.%) with double bonds, sunflower oil is the most prone to self-heating. The coconut and rapeseed oils contain double bond FAME in lesser amount, and their propensity to self-heating is relatively low.

Forecasting the fl ood situation using space images in the city of Tavda Sverdlovsk region

2018 ◽  
Vol 934 (4) ◽  
pp. 46-52
Author(s):  
A.S. Bruskova ◽  
T.I. Levitskaya ◽  
D.M. Haydukova
Keyword(s):  
Water Levels ◽  
Economic Damage ◽  
Geoinformation System ◽  
Space Images ◽  
Geoinformation Systems ◽  
Emergency Situations ◽  
The Earth ◽  
Maximum Water ◽  
The City

Flooding is a dangerous phenomenon, causing emergency situations and causing material damage, capable of damaging health, and even death of people. To reduce the risk and economic damage from flooding, it is necessary to forecast flooding areas. An effective method of forecasting emergency situations due to flooding is the method of remote sensing of the Earth with integration into geoinformation systems. With the help of satellite imagery, a model of flooding was determined based on the example of Tavda, the Sverdlovsk Region. Space images are loaded into the geoinformation system and on their basis a series of thematic layers is created, which contains information about the zones of possible flooding at given water level marks. The determination of the area of flooding is based on the calculation of the availability of maximum water levels at hydrological stations. According to the calculated security data, for each hydrological post, flood zones are constructed by interpolation between pre-calculated flood zones of standard security. The results of the work can be used by the Main Directorate of the Ministry for Emergency Situations of Russia for the Sverdlovsk Region.

scholarly journals Viscoelastometry for detecting oral anticoagulants

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Philipp Groene ◽  
Daniela Wagner ◽  
Tobias Kammerer ◽  
Lars Kellert ◽  
Andreas Giebl ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Prospective Observational Study ◽  
Oral Anticoagulants ◽  
Plasma Concentrations ◽  
Factor Xa ◽  
Clotting Time ◽  
Emergency Situations ◽  
Tissue Plasminogen ◽  
The Impact

Abstract Background Determination of anticoagulant therapy is of pronounced interest in emergency situations. However, routine tests do not provide sufficient insight. This study was performed to investigate the impact of anticoagulants on the results of viscoelastometric assays using the ClotPro device. Methods This prospective, observational study was conducted in patients receiving dabigatran, factor Xa (FXa)-inhibitors, phenprocoumon, low molecular weight heparin (LMWH) or unfractionated heparin (UFH) (local ethics committee approval number: 17–525-4). Healthy volunteers served as controls. Viscoelastometric assays were performed, including the extrinsic test (EX-test), intrinsic test (IN-test) Russel’s viper venom test (RVV-test), ecarin test (ECA-test), and the tissue plasminogen activator test (TPA-test). Results 70 patients and 10 healthy volunteers were recruited. Clotting time in the EX-test (CTEX-test) was significantly prolonged versus controls by dabigatran, FXa inhibitors and phenprocoumon. CTIN-test was prolonged by dabigatran, FXa inhibitors and UFH. Dabigatran, FXa inhibitors and UFH significantly prolonged CTRVV-test in comparison with controls (median 200, 207 and 289 vs 63 s, respectively; all p < 0.0005). Only dabigatran elicited a significant increase in CTECA-test compared to controls (median 307 vs 73 s; p < 0.0001). CTECA-test correlated strongly with dabigatran plasma concentration (measured by anti-IIa activity; r = 0.9970; p < 0.0001) and provided 100% sensitivity and 100% specificity for detecting dabigatran. Plasma concentrations (anti-XA activity) of FXa inhibitors correlated with CTRVV-test (r = 0.7998; p < 0.0001), and CTRVV-test provided 83% sensitivity and 64% specificity for detecting FXa inhibitors. Conclusions In emergency situations, ClotPro viscoelastometric assessment of whole-blood samples may help towards determining the presence and type of anticoagulant class that a patient is taking. Trial registration German clinical trials database ID: DRKS00015302.

scholarly journals Laboratory and In Situ Determination of Hydraulic Conductivity and Their Validity in Transient Seepage Analysis

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1131
Author(s):  
Soonkie Nam ◽  
Marte Gutierrez ◽  
Panayiotis Diplas ◽  
John Petrie
Keyword(s):  
Hydraulic Conductivity ◽  
Field Measurements ◽  
Natural Soil ◽  
In Situ Tests ◽  
Seepage Analysis ◽  
Soil Deposits ◽  
Seepage Modeling ◽  
Sample Disturbance

This paper critically compares the use of laboratory tests against in situ tests combined with numerical seepage modeling to determine the hydraulic conductivity of natural soil deposits. Laboratory determination of hydraulic conductivity used the constant head permeability and oedometer tests on undisturbed Shelby tube and block soil samples. The auger hole method and Guelph permeameter tests were performed in the field. Groundwater table elevations in natural soil deposits with different hydraulic conductivity values were predicted using finite element seepage modeling and compared with field measurements to assess the various test results. Hydraulic conductivity values obtained by the auger hole method provide predictions that best match the groundwater table’s observed location at the field site. This observation indicates that hydraulic conductivity determined by the in situ test represents the actual conditions in the field better than that determined in a laboratory setting. The differences between the laboratory and in situ hydraulic conductivity values can be attributed to factors such as sample disturbance, soil anisotropy, fissures and cracks, and soil structure in addition to the conceptual and procedural differences in testing methods and effects of sample size.

Micro Roughness Determination Of Periodic Microelectronics Structures Using Optical Far Field Measurements

2011 ◽  
Author(s):  
Alexandre Vauselle ◽  
Philippe Maillot ◽  
Gaëlle Georges ◽  
Carole Deumié ◽  
David G. Seiler ◽  
...  
Keyword(s):  
Field Measurements ◽  
Far Field

Corrosion Metal Loss Interaction From In-Line Inspection and How it Can Affect the Calculated Failure Pressure

2012 ◽  
Author(s):  
Lucinda Smart ◽  
Richard McNealy ◽  
Harvey Haines
Keyword(s):  
Field Measurements ◽  
Metal Loss ◽  
Data Correlation ◽  
Failure Pressure ◽  
Industry Standards ◽  
Direct Measurements ◽  
Non Destructive ◽  
Flux Leakage

In-Line Inspection (ILI) is used to prioritize metal loss conditions based on predicted failure pressure in accordance with methods prescribed in industry standards such as ASME B31G-2009. Corrosion may occur in multiple areas of metal loss that interact and may result in a lower failure pressure than if flaws were analyzed separately. The B31G standard recommends a flaw interaction criterion for ILI metal loss predictions within a longitudinal and circumferential spacing of 3 times wall thickness, but cautions that methods employed for clustering of ILI anomalies should be validated with results from direct measurements in the ditch. Recent advances in non-destructive examination (NDE) and data correlation software have enabled reliable comparisons of ILI burst pressure predictions with the results from in-ditch examination. Data correlation using pattern matching algorithms allows the consideration of detection and reporting thresholds for both ILI and field measurements, and determination of error in the calculated failure pressure prediction attributable to the flaw interaction criterion. This paper presents a case study of magnetic flux leakage ILI failure pressure predictions compared with field results obtained during excavations. The effect of interaction criterion on calculated failure pressure and the probability of an ILI measurement underestimating failure pressure have been studied. We concluded a reason failure pressure specifications do not exist for ILI measurements is because of the variety of possible interaction criteria and data thresholds that can be employed, and demonstrate herein a method for their validation.

Real-time performance of filtering facepiece respirators at the workplace/Echtzeit-Performance partikelfiltrierender Halbmasken am Arbeitsplatz

Gefahrstoffe ◽  
2019 ◽  
Vol 79 (10) ◽  
pp. 378-384
Author(s):  
C. Sun ◽  
C. Thelen ◽  
I. Sancho Sanz ◽  
A. Wittmann
Keyword(s):  
Field Measurements ◽  
Paper Mill ◽  
Measuring System ◽  
Pilot Test ◽  
Protection Factor ◽  
Workplace Performance ◽  
Geometric Means ◽  
Training Facility ◽  
Workplace Conditions

The efficacy of a respirator under real workplace conditions is presented by its workplace protection factor (WPF). The aim of this study was to assess a portable measuring system for the determination of WPF for particulate filtering facepiece respirators. WPFs of CE-marked FFP2 and FFP3 filtering facepiece respirators were measured as a pilot test conducted at two workplaces: an inter-company training facility and a paper mill, with a total of seven test subjects. Each subject was quantitatively fit tested prior to the field measurements. Two TSI PortaCount instruments measured the particle concentrations simultaneously and continuously inside and outside the respirator for 15 min, with three repetitions. The results of the fit test (overall fit factor) ranged from 22 to 199. Individual WPF results ranged from 16 to 568 for FFP2 respirators, and from 13 to 232 for FFP3 respirators. The geometric means (GM) of the WPF were 135 with a 5th percentile value of 37 (FFP2), and 47 with a 5th percentile value of 12 (FFP3). This pilot test provides a new method of evaluating the workplace performance of filtering facepiece respirators.

Consideration of Non-stationarity in the Development of Emergency Situations for the Quantitative Risk Assessment of Accidents at Hazardous Production Facilities of Oil and Product Pipelines

2021 ◽  
pp. 89-96
Author(s):  
A.M. Sverchkov ◽  
Keyword(s):  
Risk Assessment ◽  
Fire Hazard ◽  
Ignition Time ◽  
Quantitative Risk Assessment ◽  
Risk Indicators ◽  
Oil Pipeline ◽  
Emergency Situations ◽  
External Conditions ◽  
Hazardous Production ◽  
Real Practice

It is proposed to use the new approach to assessing quantitative risk indicators. This approach allows to consider the temporal non-stationarity of the number of processes, including the development of an accident and the spatial movements of people. The greatest uncertainty in the risk analysis with an explosive and fire hazard component is not the frequency of initiating events used, but, for example, data on the probability of ignition. The range of variation of this probability is about two orders of magnitude (relatively speaking, from 1 % to 100 %), and the criteria and factors that determine the choice of this value are not always clearly defined. The paper proposes an approach that considers the probability of ignition as a dependence on the time that passed after the start of emergency depressurization. Knowing this dependence, it is possible to consider several scenarios with different ignition time after the start of the release and assign certain consequences and probabilities to each scenario. Moreover, it is possible for each single scenario on a specific piece of equipment (pipeline section) to obtain non-stationary, namely time-varying potential risk fields. The example of an accident on the oil pipeline is considered, the risk indicators of such an accident are calculated, it is shown that the risks can change over time, namely they are non-stationary characteristics. Further, this fact is transformed into the development of theoretical foundations for quantitative risk assessment, considering the non-stationarity of various processes occurring during emergency situations arising during the operation of equipment, individual behavior of people and changes in external conditions. The results obtained show the importance of considering the changes that occur during an emergency on the main oil and product pipelines. It is concluded that the proposed approach allows to reduce the conservatism of assessments provided by traditional methods. In real practice this approach can reasonably reduce the risk indicators by several times, sometimes by orders of magnitude.

Sign in / Sign up

Export Citation Format

Share Document