Studies on the influence of process parameters on the protection performance of the outer layer of fire-protective clothing

2021 ◽  
pp. 152808372110545
Author(s):  
Rochak Rathour ◽  
Apurba Das ◽  
Ramasamy Alagirusamy
Keyword(s):  
Outer Layer ◽  
Protective Clothing ◽  
Thermal Protection ◽  
Regression Equations ◽  
Anova Analysis ◽  
Response Curves ◽  
Influence Of Process Parameters ◽  
System Equation ◽  
Protection Time ◽  
Predicted Values

During an operation, the turnout gear for firefighters must meet two important requirements: thermal protection and comfort. As comfort and protection are inherently incompatible, it is impossible to satisfy both. As part of this study, the outer layer of multilayered turnout suits was analyzed under the influence of various factors such as intensity of heat flux, pick density, and air space between the fabric and the sensor. Choosing Nomex IIIA was based on its inherent properties that are conductive to thermal protection. To simulate the environment encountered during firefighting, benchtop experiments were designed. A system equation for the prediction of the protection time (t-protection) was developed based on a three-factor and three-level Box–Behnken model. The predicted values of t-protection obtained for all the experimental blocks in the design space were subjected to ANOVA analysis which showed that the system equation, as well as the coefficients of linear interactive and square terms, is significant, so the system equation can be efficiently used for predicting t-protection. The validity of the system equation was verified by using the same experimental blocks and estimating t-protection using the Stoll criteria. The accuracy of the system equation was checked by comparing t-protection and t*-protection which revealed a linear relationship with a high correlation coefficient (R2 = 0.975). To analyze the effects of the independent variables on protection time, 3D surface response curves were created. The nature of the surfaces was critically analyzed by developing regression equations for the contours and the diagonals.

Real-Ear-to-Coupler Difference Predictions as a Function of Age for Two Coupling Procedures

2002 ◽  
Vol 13 (08) ◽  
pp. 407-415 ◽  
Author(s):  
Marlene P. Bagatto ◽  
Susan D. Scollie ◽  
Richard C. Seewald ◽  
K. Shane Moodie ◽  
Brenda M. Hoover
Keyword(s):  
Young Children ◽  
Infants And Children ◽  
Regression Equations ◽  
Predictive Equations ◽  
Subject Variability ◽  
Predicted Values ◽  
Age Range ◽  
Infants And Young Children

The predicted real-ear-to-coupler difference (RECD) values currently used in pediatric hearing instrument prescription methods are based on 12-month age range categories and were derived from measures using standard acoustic immittance probe tips. Consequently, the purpose of this study was to develop normative RECD predicted values for foam/acoustic immittance tips and custom earmolds across the age continuum. To this end, RECD data were collected on 392 infants and children (141 with acoustic immittance tips, 251 with earmolds) to develop normative regression equations for use in deriving continuous age predictions of RECDs for foam/acoustic immittance tips and earmolds. Owing to the substantial between-subject variability observed in the data, the predictive equations of RECDs by age (in months) resulted in only gross estimates of RECD values (i.e., within ± 4.4 dB for 95% of acoustic immittance tip measures; within ± 5.4 dB in 95% of measures with custom ear molds) across frequency. Thus, it is concluded that the estimates derived from this study should not be used to replace the more precise individual RECD measurements. Relative to previously available normative RECD values for infants and young children, however, the estimates derived through this study provide somewhat more accurate predicted values for use under those circumstances for which individual RECD measurements cannot be made.

scholarly journals Cratering for Impact of Hypervelocity Projectiles into Granite Targets within a Velocity Range of 1.91–3.99 km/s: Experiments and Analysis

2020 ◽  
Vol 10 (4) ◽  
pp. 1393
Author(s):  
Xiaofeng Wang ◽  
Jingbo Liu ◽  
Biao Wu ◽  
Defeng Kong ◽  
Jiarong Huang ◽  
...  
Keyword(s):  
Impact Velocity ◽  
Scaling Law ◽  
Density Ratio ◽  
Hypervelocity Impact ◽  
Experimental Results ◽  
Tungsten Alloy ◽  
Regression Equations ◽  
Velocity Range ◽  
Predicted Values ◽  
The Impact

To understand and analyze crater damage of rocks under hypervelocity impact, the hypervelocity impact cratering of 15 shots of hemispherical-nosed cylindrical projectiles into granite targets was studied within the impact velocity range of 1.91–3.99 km/s. The mass of each projectile was 40 g, and the length–diameter ratio was 2. Three types of metal material were adopted for the projectiles, including titanium alloy with a density of 4.44 g/cm3, steel alloy with a density of 7.81 g/cm3, and tungsten alloy with a density of 17.78 g/cm3. The projectile–target density ratio (ρp/ρt) ranged from 1.71 to 6.86. The depth–diameter ratios (H/D) of the craters yielded from the experiments were between 0.14 and 0.24. The effects of ρp/ρt and the impact velocity on the morphologies of the crater were evaluated. According to the experimental results, H/D of craters is negatively correlated with the impact velocity, whereas the correlation between H/D and ρp/ρt is weak positive. The crater parameters were expressed as power law relations of impact parameters by using scaling law analysis. The multiple regression analysis was utilized to obtain the coefficients and the exponents of the relation equations. The predicted values of the regression equations were close to the experimental results.

DEVELOPING PREDICTION EQUATIONS AND OPTIMIZING PRODUCTION OF THREE AM FUNGAL INOCULA UNDER ON-FARM CONDITIONS

2011 ◽  
Vol 47 (3) ◽  
pp. 529-537 ◽  
Author(s):  
MAHAVEER P. SHARMA ◽  
ALOK ADHOLEYA
Keyword(s):  
Mycorrhizal Fungi ◽  
Glomus Intraradices ◽  
Maximum Yield ◽  
Arbuscular Mycorrhizal ◽  
Total Production ◽  
Regression Equations ◽  
Farm Production ◽  
Predicted Values ◽  
Time Required ◽  
On Farm

SUMMARYThe production potential of three arbuscular mycorrhizal fungi (AMF), AM-1004 (Glomus intraradices), AM-1209 (mixed indigenous AMF) and AM-1207 (Mycorise, commercial inocula), were examined separately in three fractions/forms (root-based, soil-based and mixture of roots + soil) at 40, 60, 80 and 105 days in raised beds. The beds were amended with organic matter to develop regression equations for predicting optimal AM production vis-à-vis time required for particular inocula using infectious propagules (IP) as the independent variable. The IP production observed in the system was found to vary among the different inocula used. AM-1004 and AM-1207 produced significantly higher propagule counts in root or soil-based samples and a mixture of both at 105 days as compared to AM-1209. Based on two-way ANOVA, irrespective of time, AM-1004 (root/soil-based) produced a significantly larger number of propagules, whereas propagules in the crude inoculum (roots + soil) of all three inocula were not significantly different. On the other hand, irrespective of AMF, significantly more propagules (in all forms) were observed at 105 days. Similarly, irrespective of time, AM-1004 produced significantly higher root colonization (MCP, mycorrhizal colonization percentage) in all three forms (roots: 65.95%; soil: 24.32; soil + roots: 58.03%). The MCP in roots was increased significantly with time of multiplication. However, there was not much improvement in the MCP of soil or in soil + roots fractions beyond 80 days. Further, prediction of the number of IP for the three AM inocula was mathematically derived separately from the Mitscherlish-Bray equation (Y=a–b*exp (–cD). Based on the maximum yield of propagules of the three inocula observed and fitted into equations, root-based AM-1004 and AM-1209 inocula were found to be more efficient in producing propagules in 65 days as compared to AM-1207, which produced propagules in 76 days. While comparing the overall combinations, AM-1004 and AM-1209 inocula used either as roots, soil or a mixture of both and have greater potential in producing more propagules in the shortest span of time. While taking into account the predicted values of AM-1209 crude inoculum, about 12 IP g−1substrate can be achieved in 72 days. Therefore, if a farmer uses crude inocula (having zero time IP of about 0.8/g substrate) of AM 1209, a total production of about 12.12 million IP/m3can be achieved in 72 days. These can be used for on-farm production.

Optimization on Uniform Design for Preparing Monodisperse P(St/BA/AA) Microsphere by Dispersion Polymerization

2011 ◽  
Vol 225-226 ◽  
pp. 1167-1170
Author(s):  
Jin Xian Lin
Keyword(s):  
Dispersion Polymerization ◽  
Design Method ◽  
Uniform Design ◽  
Regression Equation ◽  
Polymerization Reaction ◽  
Regression Equations ◽  
Stabilizer Concentration ◽  
Mechanism Research ◽  
Predicted Values ◽  
Uniform Design Method

The uniform design method is used to arrange experiment of dispersion polymerization of styrene, butyl acrylate and acryl acid. The stepwise regression technique is adopted to analyze the results. The mathematical models are built by regression equations between the microsphere conversion rate, the size and its distribution. There are many influencing factors, such as, 3 monomer concentrations, stabilizer concentration, initiator concentration, ratio of alcohol and water, temperature established, and their reliabilities evaluated. Although the predicted values from regression equation different from the observed values (relative divergences less than 10%)，the regression equation can be used for designing particles and mechanism research. All above researches can be used for optimizing dispersion polymerization reaction conditions.

scholarly journals Comparison of Direct-reading and Gravimetric Methods of Particle Measurement in a Science Building, Silpakorn University

2021 ◽  
pp. 132-143
Author(s):  
Aungsiri Tipayarom ◽  
Prayad Sangngam ◽  
Siraphop Pinitkarn
Keyword(s):  
Gravimetric Method ◽  
Ordinary Least Squares ◽  
Gravimetric Analysis ◽  
Regression Equations ◽  
Direct Reading ◽  
Ols Regression ◽  
Pm10 And Pm2.5 ◽  
Science Building ◽  
Predicted Values ◽  
Comparison Of The Results

This study aimed to develop relationships between particulate matter (PM) concentrations obtained from a direct-reading instrument to those from a gravimetric method. TSI DustTrak II Aerosol Monitors (Model 8530), a direct-reading instrument for PM10 and PM2.5 measurement, together with personal air pumps connected to a Sensidyne cyclone and a SKC Personal Environmental Monitor (PEM) for gravimetric PM10 and PM2.5 measurements respectively were deployed in the Faculty of Science building, Silpakorn University, Nakhon Pathom, Thailand. Comparison of the results from each instrument indicated that PM10 and PM2.5 concentrations obtained from the TSI DustTrak were higher. The linear relationship from ordinary least squares (OLS) regression between PM10 data determined by TSI DustTrak (x) and Sensidyne cyclone (y ̂) was significant (R2=0.92) and could be represented as y ̂ = 0.272x. For PM2.5, the relationship between concentrations determined by TSI DustTrak (x) and SKC PEM (y ̂) was also significant (R2=0.92) and represented by y ̂ = 4.848√x. Validation of both equations was undertaken by comparing predicted values from these relationships against the actual concentrations found by gravimetric analysis, with R2=1.0 and 0.92 for PM10 and PM2.5, respectively. It is suggested that these site-specific OLS regression equations can provide fast and convenient estimation of concentrations derived by gravimetric analysis from direct-reading TSI DustTrak monitor data.

scholarly journals Immediate Effects of Sforzesco® Bracing on Respiratory Function in Adolescents with Idiopathic Scoliosis

Healthcare ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1372
Author(s):  
Fabrizio Di Maria ◽  
Andrea Vescio ◽  
Alessia Caldaci ◽  
Ada Vancheri ◽  
Chiara Di Maria ◽  
...  
Keyword(s):  
Lung Function ◽  
Idiopathic Scoliosis ◽  
Lung Volume ◽  
Repeated Measures ◽  
Respiratory Function ◽  
Regression Equations ◽  
Lung Volumes ◽  
Perceived Effort ◽  
Predicted Values ◽  
The One

The thoraco-lumbar bracing is an effective management of adolescent idiopathic scoliosis (AIS). Studies have shown that brace wearing reduces lung volume. Whether or not the Sforzesco brace, frequently used in Italy, affects lung volume has not been investigated. We studied the immediate effect of Sforzesco bracing on lung volumes in 11 AIS patients (10 F, 1 M; aged 13.6 ± 1.6 yrs) mean Cobb angle 26 ± 4.49 degrees. Lung function variables and the perceived respiratory effort were recorded twice, before and 5 min after bracing. The one-way analysis of variance repeated measures, and multiple comparison tests, showed that means of unbraced variables were not significantly different from the corresponding means of predicted values, whereas means under brace were significantly lower (p < 0.05) compared to both predicted and baseline values of respiratory variables. In addition, a significant correlation (p < 0.0001) was found between unbraced and braced values, and linear regression equations were calculated. A significant but clinically unimportant increase in perceived effort was observed under the brace. In conclusion, data indicate that lung function is not impaired in moderate AIS and that wearing the Sforzesco brace causes an immediate, predictable reduction of lung volumes. Data also suggest that the respiratory discomfort during brace wearing could not be due to respiratory function defects.

scholarly journals Thermal Properties of Special New Generation Personal Protective Clothing for Firefighters-Rescuers

2021 ◽  
Vol 1 (80) ◽  
pp. 45-67
Author(s):  
Marzena Rachwał ◽  
Małgorzata Majder-Łopatka ◽  
Tomasz Węsierski ◽  
Artur Ankowski ◽  
Magdalena Młynarczyk ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Thermal Insulation ◽  
Protective Clothing ◽  
Body Shape ◽  
Thermal Protection ◽  
Thermal Manikin ◽  
Protective Equipment ◽  
Everyday Work ◽  
New Generation ◽  
Full Body

Every day, firefighters put their health and life at risk by saving people and their property not only during fires, but by being always ready during all kinds of unfortunate events. Therefore, they need special personal protective equipment, including protective clothing. The purpose of the study was to compare thermal properties of new (PROTON and SYRIUSZ) and old (US-03) personal protective clothing for firefighters. Measurements of thermal insulation (total, effective and local) were carried out using a full body shape thermal manikin Newton consisting of 34 segments, in which temperature and heat flux were controlled independently. Results of the total thermal insulation of the entire clothing reveal differences between all three models. The lowest values were noticed for the model PROTON with light and shorter jacket and the highest values of thermal insulation for the new model SYRIUSZ, indicating that this model protect the user against heat most effectively. New models of personal protective clothing for firefighters should be recommended for use in everyday work, because they are characterized by better parameters than the previous type of protective clothing, both in terms of thermal protection and mobility.

On the Effectiveness of Temperature-Responsive Protective Fabric Incorporated With Shape Memory Alloy (SMA) Under Radiant Heat Exposure

2019 ◽  
Vol 38 (3) ◽  
pp. 212-224 ◽  
Author(s):  
Lijun Wang ◽  
Yehu Lu ◽  
Jiazhen He
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Protective Clothing ◽  
Thermal Protection ◽  
Heat Exposure ◽  
Radiant Heat ◽  
Air Gap ◽  
Environment Change ◽  
Temperature Responsive ◽  
Thermal Insulating

To improve thermal protection of protective clothing, temperature-responsive protective fabrics incorporated with shape memory alloy (SMA) springs varying on four different deformation heights and five types arrangement modes were designed. The thermal protection was investigated under radiant heat exposure of 0.39 cal/cm2 s. The results indicated that the air gap between fabric layers produced by SMA springs effectively improved protective performance. The thermal protection of fabrics with different SAM arrangement modes and sizes showed different trends, and the interaction effects of arrangement mode and size were analyzed. Moreover, the optimized arrangement and size of SMA springs were suggested. The regression models were established to assess the relationship between the air gap and thermal protection. This study demonstrated that the combination of flame-resistant fabric with SMA was feasible to develop temperature-responsive protective clothing because it could improve thermal insulating property by producing intelligent air gaps that responded to environment change.

Evaluation method for thermal protection of firefighters’ clothing in high-temperature and high-humidity condition

2016 ◽  
Vol 28 (4) ◽  
pp. 429-448 ◽  
Author(s):  
Yun Su ◽  
Yunyi Wang ◽  
Jun Li
Keyword(s):  
High Temperature ◽  
Protective Clothing ◽  
Thermal Protection ◽  
Evaluation Methods ◽  
Moisture Distribution ◽  
High Humidity ◽  
Thermal Hazards ◽  
Content Type ◽  
Humidity Condition ◽  
High Humidity Condition

Purpose – The purpose of this paper is to provide the details of developments to researchers in test apparatus and evaluation methods to rate the thermal protective performance (TPP) of firefighters’ clothing under high-temperature and high-humidity condition. Design/methodology/approach – This review paper describes the influence laws of moisture on thermal protection and the moisture distribution in actual fire environment. Different evaluation methods used for assessing the effect of moisture on the TPP were investigated, with an emphasis on test devices, evaluation indexes as well as their relationship and limitations. Findings – The moisture from the ambient, clothing and human perspiration plays an important role in determining the TPP of firefighter protective clothing. It is obvious that research on moisture-driven heat transfer in firefighter’s clothing system are comparatively little, primarily focussing on pre-wetted methods of multi-layer fabric. Further studies should be conducted to develop more standardized moistening systems and improve the current calculation methods for evaluating the performance of protective clothing. New explorations for heat and moisture transfer mechanism in protective clothing should be investigated. Practical implications – Protective clothing is the efficient way to provide fire-fighting occupational safety. To accurately evaluate the TPP of protective clothing under high-temperature and high-humidity condition will help to optimize the clothing performance and choose the proper clothing for providing firefighters with the best protection under multiple thermal hazards. Originality/value – This paper is offered as a concise reference for scientific community further research in the area of the TPP evaluation methods under high-temperature and high-humidity condition.

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