scholarly journals Experimental Study on the Thermoplastic Dripping and Flame Spread Behaviors of Energized Electrical Wire under Reduced Atmospheric Pressure

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 346
Author(s):  
Hao He ◽  
Qixing Zhang ◽  
Long Shi ◽  
Haihang Li ◽  
Dongmei Huang ◽  
...  
Keyword(s):  
Flame Spread ◽  
Fire Risk ◽  
Electrical Current ◽  
Wire Surface ◽  
Short Term ◽  
Reduced Pressure ◽  
Electrical Currents ◽  
Electrical Wire ◽  
Short Period ◽  
Increasing Trends

Flame spread over wire surface is different from other solid fires as it is usually accompanied by melting and dripping processes. Although the related behaviors at reduced pressure (20–100 kPa) are significant to those fire risk evaluations, very few studies have been undertaken on this matter. Therefore, the thermoplastic dripping and flame spread behaviors of energized polyethylene insulated copper wires were investigated experimentally at reduced pressure. It was known from experimental results that the dripping frequency increases, showing a relatively smooth (linear) and rapid (power) increasing trends under high and low electrical currents, respectively. A short-period flame disappearance was observed during the dripping process, which is unique for the energized wire at reduced pressure. The bright flame can disappear for several seconds and then show again after the dripping. While at 20 kPa or lower, the wire flame would turn to a completed extinguishment after the dripping. A critical dripping point was proposed to show the minimal required electrical current to sustain the flame spearing. The critical current changes smoothly during 100–80 kPa and decreases rapidly at 80–60 kPa. Additionally, the dripping phenomenon can stop or delay the flame spread, partly because of the short-term flame disappearance.

scholarly journals Thermodynamic and Kinetic Characteristics of Combustion of Discrete Polymethyl Methacrylate Plates with Different Spacings in Concave Building Facades

Polymers ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 167
Author(s):  
Weiguang An ◽  
Lujun Peng ◽  
Minglun Cai ◽  
Kaiyang Hu ◽  
Song Li ◽  
...  
Keyword(s):  
Polymethyl Methacrylate ◽  
Flame Spread ◽  
Structure Factor ◽  
Turning Point ◽  
Fire Risk ◽  
Flame Height ◽  
Hazard Evaluation ◽  
Spread Rate ◽  
Building Facades ◽  
Flame Spread Rate

Polymethyl methacrylate plates are widely applied to buildings, producing significant fire hazards. It lacks a theoretical basis for the fire risk assessment of polymethyl methacrylate in concave building facades. Therefore, experimental methods are used to investigate combustion characteristics of discrete polymethyl methacrylate plates in a concave building facade. Influences of fuel coverage and structure factor are investigated, which is scant in previous works. When structure factor is invariable, average flame height increases first and then decreases as fuel coverage increases, and the turning point is between 0.64 and 0.76. In total, three different patterns of pyrolysis front propagation are first observed for different fuel coverages. Flame spread rate first increases and then decreases as fuel coverage rises, and the turning point is also between 0.64 and 0.76. When fuel coverage is invariable, the flame spread rate first increases and then decreases with increasing structure factor, and the turning point is 1.2. A model for predicting the flame spread rate of discrete polymethyl methacrylate is also developed. The predicted values are consistent with experimental results. Fuel spread rate of discrete polymethyl methacrylate rises as the fuel coverage increases. The above results are beneficial for thermal hazard evaluation and fire safety design of polymethyl methacrylate used in buildings.

scholarly journals Effects of different returning method combined with decomposer on decomposition of organic components of straw and soil fertility

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiao Wang ◽  
Xuexin Wang ◽  
Peng Geng ◽  
Qian Yang ◽  
Kun Chen ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Fertility ◽  
Decomposition Rate ◽  
Microbial Biomass Carbon ◽  
No Tillage ◽  
Short Term ◽  
Straw Decomposition ◽  
Short Period ◽  
Straw Return ◽  
Forms Of Carbon

AbstractIn view of the problems of low straw decomposition rates and reduced soil fertility in southern Liaoning, China, we investigated the effects of no-tillage mode (NT), deep loosening + deep rotary tillage mode (PT), rotary tillage mode (RT) and the addition of decomposing agent (the next is called a decomposer) (NT + S, PT + S, RT + S) on the decomposition proportion of straw, respectively, by using the nylon net bag method in combination with 365-day field plot experiments. The decomposition rules of cellulose, hemicellulose and lignin as well as the dynamics of soil organic carbon (SOC), soil microbial biomass carbon (MBC) and soil dissolved organic carbon (DOC) in straw returned to the field for 15, 35, 55, 75, 95, 145 and 365 days were analyzed. The results showed that in the short term, the decomposition of straw was better in both the rotray tillage and deep loosening + deep rotary modes than in the no-tillage mode, and the addition of decomposer significantly promoted the decomposition of straw and the release of carbon from straw, among them, the RT + S treatment had the highest straw decomposition proportion and carbon release proportion in all sampling periods. After a one year experimental cycle, the RT + S treatment showed the highest proportion of cellulose, hemicellulose and lignin decomposition with 35.49%, 84.23% and 85.50%, respectively, and soil SOC, MBC and DOC contents were also higher than the other treatments with an increase of 2.30 g kg−1, 14.22 mg kg−1 and 25.10 mg kg−1, respectively, compared to the pre-experimental soil. Our results show that in the short term, to accelerate the decomposition rate of returned straw and increase the content of various forms of carbon in soil, rotary tillage can be used to return the straw to the field, while also spraying straw decomposer on its surface. This experiment used a new straw decomposer rich in a variety of microorganisms, combined with the comparison of a variety of straw return modes, and in-depth study of straw decomposition effects of cellulose, hemicellulose and lignin. Thus, a scheme that can effectively improve the decomposition rate of straw and the content of various forms of organic carbon in soil within a short period of time was explored to provide theoretical support for the southern Liaoning.

EXPRESS: Short-term upper limb immobilization impairs grasp representation

2020 ◽  
pp. 174702182098552
Author(s):  
Lucette Toussaint ◽  
Aurore Meugnot ◽  
Christel Bidet-Ildei
Keyword(s):  
Response Times ◽  
Motor Program ◽  
Control Group ◽  
Short Term ◽  
Small Sphere ◽  
Large Sphere ◽  
Short Period ◽  
Limb Immobilization ◽  
Laterality Task ◽  
Sensorimotor Processes

The present experiment aimed to gain more information on the effect of limb nonuse on the cognitive level of actions and, more specifically, on the content of the motor program used for grasping an object. For that purpose, we used a hand-grasping laterality task that is known to contain concrete information on manipulation activity. Two groups participated in the experiment: an immobilized group, including participants whose right hand and arm were fixed with a rigid splint and an immobilization vest for 24 hours, and a control group, including participants who did not undergo the immobilization procedure. The main results confirmed a slowdown of sensorimotor processes, which is highlighted in the literature, with slower response times when the participants identified the laterality of hand images that corresponded to the immobilized hand. Importantly, the grip-precision effect, highlighted by slower response times for hands grasping a small sphere versus a large sphere, is impaired by 24 hours of limb nonuse. Overall, this study provided additional evidence of the disengagement of sensorimotor processes due to a short period of limb immobilization.

scholarly journals Irreversible Electroporation for Prostate Cancer

Life ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 490
Author(s):  
Sean Ong ◽  
Matthew Leonardo ◽  
Thilakavathi Chengodu ◽  
Dominic Bagguley ◽  
Nathan Lawrentschuk
Keyword(s):  
Prostate Cancer ◽  
Functional Outcomes ◽  
Irreversible Electroporation ◽  
Focal Therapy ◽  
Safe Procedure ◽  
Short Term ◽  
Electrical Currents ◽  
Treatment Side Effects ◽  
Oncological Outcomes ◽  
Treat All

Although it can be lethal in its advanced stage, prostate cancer can be effectively treated when it is localised. Traditionally, radical prostatectomy (RP) or radiotherapy (RT) were used to treat all men with localised prostate cancer; however, this has significant risks of post-treatment side effects. Focal therapy has emerged as a potential form of treatment that can achieve similar oncological outcomes to radical treatment while preserving functional outcomes and decreasing rates of adverse effects. Irreversible electroporation (IRE) is one such form of focal therapy which utilises pulsatile electrical currents to ablate tissue. This modality of treatment is still in an early research phase, with studies showing that IRE is a safe procedure that can offer good short-term oncological outcomes whilst carrying a lower risk of poor functional outcomes. We believe that based on these results, future well-designed clinical trials are warranted to truly assess its efficacy in treating men with localised prostate cancer.

Uniformity of Electrical Current for Underwater Electrical Wire Array Explosion

2021 ◽  
Author(s):  
Zhigang Liu ◽  
Dun Qian ◽  
Xiaobing Zou ◽  
Xinxin Wang
Keyword(s):  
Wire Array ◽  
Electrical Current ◽  
Electrical Wire

scholarly journals Clinical and microbiological evaluation of one-stage full-mouth disinfection: a short-term study

2013 ◽  
Vol 42 (4) ◽  
pp. 298-303
Author(s):  
José Roberto Cortelli ◽  
Marcos Vinicius Moreira de Castro ◽  
Rodrigo Dalla Pria Balejo ◽  
Camila Oliveira de Alencar ◽  
Antonio Carlos Gargioni Filho ◽  
...  
Keyword(s):  
Chronic Periodontitis ◽  
Bacterial Load ◽  
Periodontal Treatment ◽  
Periodontal Pocket ◽  
Short Term ◽  
Term Study ◽  
One Stage ◽  
Short Term Study ◽  
Short Period ◽  
Full Mouth Disinfection

INTRODUCTION: Patients seem to adhere better to short-term periodontal treatment schemes. Besides, time-reduced treatments are more cost-effective. However, the degree of benefits related to this type of treatment still requires additional investigations. AIM: The present short-term study evaluated clinical and microbiological outcomes, from baseline to 3-months, of chronic periodontitis subjects treated by the one-stage full-mouth disinfection protocol. MATERIAL AND METHOD: Sixteen chronic periodontitis subjects (mean-age 49.87 ± 8.22) who met inclusion/exclusion criteria were included. A calibrated examiner measured whole-mouth plaque and gingival indices, periodontal pocket depth and clinical attachment level at baseline and at 3-months. Subgingival samples were also collected from the 5 most diseased periodontal sites to determine total bacterial load and levels of P. gingivalis and S. oralis by real time qPCR. Periodontal treatment consisted of full-mouth manual debridement plus wide intraoral use of chlorhexidine in gel and solution. Additionally, after debridement, individuals rinsed 0.12% chlorhexidine at home twice a day for the following 2 months. Data monitored were compared by paired Student-t test (p<0.05). RESULT: Statistical analysis revealed that, in general, one-stage full-mouth disinfection treatment provided significant clinical and microbiological improvements at 3-months. Total bacterial load showed one of the most pronounced reductions from baseline to 3-months (p=0.0001). Also, subgingival levels P. gingivalis and S. oralis reduced overtime. CONCLUSION: After a short period of monitoring, chronic periodontitis subjects showed clinical and microbial improvements following one-stage full-mouth disinfection treatment.

scholarly journals Biodegradable Flame Retardants for Biodegradable Polymer

Biomolecules ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1038
Author(s):  
Muhammad Maqsood ◽  
Gunnar Seide
Keyword(s):  
Renewable Resources ◽  
Flame Retardants ◽  
Fire Risk ◽  
Polymeric Materials ◽  
Good Choice ◽  
Airborne Particle ◽  
Short Term ◽  
Renewable Materials ◽  
Long Time ◽  
Significant Attention

To improve sustainability of polymers and to reduce carbon footprint, polymers from renewable resources are given significant attention due to the developing concern over environmental protection. The renewable materials are progressively used in many technical applications instead of short-term-use products. However, among other applications, the flame retardancy of such polymers needs to be improved for technical applications due to potential fire risk and their involvement in our daily life. To overcome this potential risk, various flame retardants (FRs) compounds based on conventional and non-conventional approaches such as inorganic FRs, nitrogen-based FRs, halogenated FRs and nanofillers were synthesized. However, most of the conventional FRs are non-biodegradable and if disposed in the landfill, microorganisms in the soil or water cannot degrade them. Hence, they remain in the environment for long time and may find their way not only in the food chain but can also easily attach to any airborne particle and can travel distances and may end up in freshwater, food products, ecosystems, or even can be inhaled if they are present in the air. Furthermore, it is not a good choice to use non-biodegradable FRs in biodegradable polymers such as polylactic acid (PLA). Therefore, the goal of this review paper is to promote the use of biodegradable and bio-based compounds for flame retardants used in polymeric materials.

scholarly journals Post-Wildfire Logging Hinders Regeneration and Increases Fire Risk

Science ◽  
2006 ◽  
Vol 311 (5759) ◽  
pp. 352-352 ◽  
Author(s):  
D. C. Donato ◽  
J. B. Fontaine ◽  
J. L. Campbell ◽  
W. D. Robinson ◽  
J. B. Kauffman ◽  
...  
Keyword(s):  
Fire Risk ◽  
Fuel Reduction ◽  
Short Term ◽  
High Severity ◽  
Fuel Loads ◽  
Conifer Regeneration ◽  
Biscuit Fire ◽  
Additional Reduction

We present data from a study of early conifer regeneration and fuel loads after the 2002 Biscuit Fire, Oregon, USA, with and without postfire logging. Natural conifer regeneration was abundant after the high-severity fire. Postfire logging reduced median regeneration density by 71%, significantly increased downed woody fuels, and thus increased short-term fire risk. Additional reduction of fuels is necessary for effective mitigation of fire risk. Postfire logging can be counterproductive to the goals of forest regenration and fuel reduction.

scholarly journals Observations of rapid-fire event tremor at Lascar volcano, Chile

1996 ◽  
Vol 39 (2) ◽  
Author(s):  
G. Asch ◽  
K. Wylegalla ◽  
M. Hellweg ◽  
D. Seidl ◽  
H. Rademacher
Keyword(s):  
Fractal Structure ◽  
Seismic Station ◽  
Active Volcano ◽  
Short Term ◽  
Fire Event ◽  
Local Seismicity ◽  
Short Period ◽  
Wide Range ◽  
Lascar Volcano

During the Proyecto de Investigaciòn Sismològica de la Cordillera Occidental (PISCO '94) in the Atacama desert of Northern Chile, a continuously recording broadband seismic station was installed to the NW of the currently active volcano, Lascar. For the month of April, 1994, an additional network of three, short period, three-component stations was deployed around the volcano to help discriminate its seismic signals from other local seismicity. During the deployment, the volcanic activity at Lascar appeared to be limited mainly to the emission of steam and SO2. Tremor from Lascar is a random, «rapid-fire» series of events with a wide range of amplitudes and a quasi-fractal structure. The tremor is generated by an ensemble of independent elementary sources clustered in the volcanic edifice. In the short-term, the excitation of the sources fluctuates strongly, while the long-term power spectrum is very stationary.

scholarly journals Study of Downward Flame Spread and Fire Risk Evaluation of the Thermoplastic Materials

2018 ◽  
Vol 211 ◽  
pp. 590-598 ◽  
Author(s):  
Ruo-wen Zong ◽  
Jie Ren ◽  
Xi-ping Liu ◽  
You-ran Zhi
Keyword(s):  
Flame Spread ◽  
Risk Evaluation ◽  
Fire Risk ◽  
Downward Flame Spread
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