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

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.

Scale Control for Long Term Well and Facility Preservation

Oilfield scale and corrosion at oil and gas wells and topside facilities are well known problems. There are many studies towards the control and mitigation of scaling risk during production. However, there has been limited research conducted to investigate the effectiveness of scale control approaches for the preservation of wells and facility during a potential long term shut-in period, which could last more than 6 months. Due to low oil price and harsh economic environment, the need to shut-in wells and facilities can become necessary for operations. Understanding of scale control for a long term period is important to ensure both subsurface and surface production integrity during the shut-in period. The right strategy and treatment approaches in scale management will reduce reservoir and facility damage as well as the resulting cost for mitigation. In this paper, we will review and assess the scale risk for different scenarios for operation shut-in periods and utilize laboratory study to improve the understanding of long-term impact and identify appropriate mitigation strategy. Simulated brine compositions from both conventional and unconventional fields are tested. Commercially available scale inhibitors are used for testing. Various conditions including temperature (131-171 °F), saturation index (1.28-1.73), pH (7.04-8.03) and ratio of scaling ions are evaluated. The tested inhibitor dosage range was 0-300 mg/L. Inhibitor-brine incompatibility was also investigated. Sulfate and carbonate scales such as barium sulfate, strontium sulfate and calcium carbonate are studied as example. This paper will provide an important guidance for the management of well shut- in scenarios for the industry, for both conventional and unconventional fields. Performance of two scale inhibitors for same water composition are demonstrated. The efficiency of scale inhibitor #2 is lower than that of inhibitor #1. A linear correlation is observed for long term scale inhibitor performance in this case. Protection time is thus predicted from data collected from the first 8-week experiments. The predicted protection time at 250 mg/L of inhibitor A and B is 100 weeks and 16 weeks respectively. The actual protection time will be compared to the predicted value. The inhibitor-rock interaction has also been preliminarily studied. The effects of inhibitor adsorption onto formation rock should be considered for chemical treatment design and performance/dosage optimization. This study provides novel information of scale control in a much longer time frame (up to 6 months). Various parameters may have effects on their long term control. Results will benefit the chemical selection and evaluation for long term well shut-in scenario. In addition, brine-inhibitor compatibility is evaluated simultaneously.

An assessment of canine ectoparasiticide administration compliance in the United States based on timing of ectoparasiticide purchases recorded in veterinary hospital transactions.

Background: This study evaluated the timing of dog owner ectoparasiticide purchases to estimate administration compliance and assess the consequent impact of dose purchase gaps on the proportion of time that dogs are protected over a 12-month period. Methods: Ectoparasiticide purchase transactions over a 12-month period were evaluated for dogs from 626 U.S. veterinary hospitals to determine dose purchase timing and identify consequent gaps between dose administration. Orally administered prescription ectoparasitic medications with active ingredients from the isoxazoline family (afoxolaner, fluralaner, lotilaner, or sarolaner) are included in the analysis. A period was calculated for each of the four isoxazoline-containing medications that represented the duration of protection provided by two doses of ectoparasiticide plus the average gap between these two doses. The maximum percentage of time possible for ectoparasiticide protection for this aggregate period was then calculated for each active. Results: Ectoparasiticide transaction records were analyzed for 506,637 dogs. Of these, 43% of dog owners purchased just one dose over the 12 months. If a dog owner purchased more than one dose, then the timing of these transactions could create a time gap between the completion of ectoparasite protection from the first dose and onset of protection from the subsequent purchase and administration of the second dose. Such gaps were observed in purchases made by 31-65% of dog owners depending on the selected active ingredient and number of doses. The average gap duration between dose purchases was calculated for all possible dose combinations over 12 months of ectoparasite protection. Time gaps between the first and second doses are as follows: for sarolaner (20.3 weeks), afoxolaner (12.9 weeks), fluralaner (12.8 weeks), and lotilaner (8.9 weeks). The proportion of time when protection was provided during the aggregate period between administration of the first and second doses was fluralaner 65%, lotilaner 49%, afoxolaner 40,% and sarolaner 30%. Conclusions: Dog owner ectoparasiticide purchase transactions show that there are time gaps between doses leading to reduced ectoparasite protection. The longer re-administration interval of fluralaner, which results from its extended duration, results in dog owners gaining the greatest proportion of ectoparasite protection time compared with shorter-acting monthly re-treatment medications.

Repellency of Veratraldehyde (3,4-Dimethoxy Benzaldehyde) against Mosquito Females and Tick Nymphs

Arthropod-borne infectious diseases cause many deaths and a major economic burden worldwide. Repellents play an important role in protecting people from infectious biting arthropods. The repellency of veratraldehyde, a known food additive, and the WJ-1041 formulation containing 10% veratraldehyde was tested against Aedes albopictus and Culex pipiens pallens females and Haemaphysalis longicornis nymphs using arm-in-cage, indoor or filter paper tests. Veratraldehyde exhibited repellency similar to or lower than that of n,n-diethyl-meta-toluamide (DEET) against A. albopictus, but in H. longicornis, the activity of veratraldehyde was better than that of DEET. The repellency of the 10% veratraldehyde solution was comparable to that of 20% DEET against the two mosquitoes. When comparing repellency between the WJ-1041 formulation (10% veratraldehyde) and 10% DEET against C. pipiens pallens, A. Albopictus and H. longicornis, the two showed similar repellency and complete protection time (CPT) values. However, there was a small difference depending on the tested insects. The absorption of veratraldehyde via skin was minimal, if at all. The pharmacokinetic parameters (Cmax and Tmax) of veratraldehyde in blood samples of rats were not different from those of the control group. Based on these results, veratraldehyde has high potential to be commercialized as a repellent agent against infectious disease-borne pests in the near future.

COVID-19 Vaccines: A Review of the Safety and Efficacy of Current Clinical Trials

Various strategies have been designed to contain the COVID-19 pandemic. Among them, vaccine development is high on the agenda in spite of the unknown duration of the protection time. Various vaccines have been under clinical trials with promising results in different countries. The protective efficacy and the short-term and long-term side effects of the vaccines are of major concern. Therefore, comparing the protective efficacy and risks of vaccination is essential for the global control of COVID-19 through herd immunity. This study reviews the most recent data of 12 vaccines to evaluate their efficacy, safety profile and usage in various populations.

Evaluation of a Novel User-Friendly Arthropod Repellent Gel, Verdegen

Hand sanitizers are developed as alcohol-based liquid gel formulations, generally used to decrease the amount of infectious agents on human hands. Verdegen, LLC proposed to prepare an arthropod repellent gel for public use when the recent outbreaks of Zika infection vectored through Aedes mosquitoes in the American continents prompted multi-faceted emergency measures. Four different gel formulations were developed, comprising two of the most efficacious commercial arthropod repellent active ingredients, N,N-diethyl-3-methyl benzamide (deet) and 2-(2-hydroxyethyl)-1-piperidinecarboxylic acid 1-methylpropyl ester (picaridin), each at different concentrations (20 and 33% deet, or 20 and 33% picaridin). Compliance with the use of topical arthropod repellents remains an issue among military personnel. One of the most common complaints by Soldiers is that they do not like how the repellents applied on their skin leave behind an oily or greasy residue. These new gel formulations offer a user-friendly alternative for commonly used arthropod repellents formulations for the military and civilian personnel. We tested the efficacy and protection time of these new gel formulations in comparison with the commercially available cream formulations of deet and picaridin at similar concentrations. Our data show that gel formulations have better topical attributes, and offer equal or better biting protection for up to 48 h against host-seeking Aedes aegypti (L.) (Diptera: Culicidae) female mosquitoes.

Natural Anophelin mosquito repellents and phytochemical analysis of ethanol and hexane leaf extracts from four plant species

Currently mosquitoes control is the cornerstone to minimize the rising number of mosquito borne diseases. There is an urgent need looking for alternatives to the current reliance on synthetic insecticides for the vectors control. Application of active toxic agents from plant extracts as an alternative control strategy was available from ancient times. These are non-toxic, easily available at affordable prices, biodegradable and show broad-spectrum target-specific activities against different species of vectors. Natural products with repellency properties are urgently needed. An insect repellent works by masking human scent, and a number of natural and synthetic mosquito repellents were studied. The main aim of this study was to identify the phytochemicals and compare their potentials as mosquito repellents from the ethanol (Et. OH) and hexane (hex) leaf extracts (LEs) of Ocimum basilicum, Coleus forskohlii, Eucalyptus camaldulensis and Cymbopogon flexuosus under laboratory conditions at 50 and 100% concentrations. Phytochemical analysis showed that alkaloids, saponins, flavonoids, terpenes, tannins and terpenoids were present/or absent in the 4 plant-LEs. At 50% concentration of Et. OH extracts, C. forskohlii exhibited higher repellency potential on Anopheles gambiae with protection time of 137.3 min, while O. basilicum, E. camaldulensis and Cy. flexuosus registered protection time of 30.6, 15.3 and 19 min, respectively. At 100% concentration of ethanol- extracts, C. forskohlii caused the highest protection time against the vector with protection time of 182 min. O. basilicum, E. camaldulensis and Cy. flexuosus were equally less potent against the insect, with protection time 42.6, 32.6 and 28 min, respectively. Regarding hex-extract, at 50% concentration of C. forskohlii, the highest repellency potential , with protection time of 174 was registered, while O. basilicum, E. camaldulensis and Cy. flexuosus registered protection times of 44, 18 and 28.6 min, respectively. However, the 100% concentration of Et. OH-extracts of, C. forskohlii and O. basilicum exhibited the highest protection time, with protection times of 228 and 116min, respectively. E. camaldulensis and Cy. flexuosus were less potent, with protection times 28.6 and 54.6 min, respectively. The EOs of C. forskohlii and O. basilicum L EOs proved to have potentials as repellency agents against Anopheles. GC-MS analysis of the extracts identified the compounds of both solvents extracts and the terpens were the major compounds. According to the results, further studies are required, especially on the extracts of basil and coleus since they proved to be effective.

Research on the effects of fly ash and silica fume on some properties of high-strength concrete for the construction building of coastal areas

The sustainability of constructions depends on the resistance of concrete and steel reinforcement to physical and chemical aggressors from the environment. High – strength concrete with a high consistency, low permeability and resistance to environmental erosion, is preferred to be used in infrastructure construction, especially in coastal and islands areas. This paper aims to study on the mechanical properties of high-strength concrete using a mixture of fly ash and silica fume additive. Experimental obtained results show that high-strength concrete containing fly ash and silica fume with different mixing ratios have good performance (spread: 390 ÷ 625 mm and slump: 14 ÷ 20,5cm) and high compressive strength at 28 days (47 to 75MPa). In addition, the protection time of steel reinforcement according to NT Build 356-2009 can reach 85 days for samples containing 10% silica fume. This result shows that the high-strength concrete made from a mixture of fly ash and silica fume can be used in coastal and island infrastructure.

In vivo Evaluation of the Repellency Effects of Nanoemulsion of Mentha piperita and Eucalyptus globulus Essential Oils against mosquitoes

Introduction: The present study aimed to prepare Nanoemulsions of Mentha piperita and Eucalyptus globulus essential oils and comparison of the repellant activity of them with normal essential oils and DEET in the field conditions. Methods: To determine the protection and failure time of the essential oils and DEET in the field condition against natural population of night biting culicid mosquitoes, 4 human volunteers participated in night biting test. GC-MS was used to determine the essential oil components and the Dynamic Light Scattering device was used to measure droplet size and zeta potential. Results: The relative abundance of more common species captured in this study was 40.09% and 31.65% for Anopheles superpictus, and Culex pipiens, respectively. Based on the results, the protection time of nanoemulsions of M. piperita 50% against night biting mosquitoes was 4.96±0.21 h. Also, the protection for nanoemulsions essential oil 50% of E. globulus was 6.06±0.20 h. Comparison of the results showed that the protection time of nanoemulsions of M. piperita and E. globulus was significantly higher than of their normal essential oils (P˂0.01). Also, the protection time of DEET (as a gold standard) was significantly higher than of normal essential oil and nanoemulsions of M. piperita (P˂0.01), but there is no significant difference between DEET and nanoemulsions of E. globulus (P˃0.01). Conclusion: Due to the safety and biocompatibility of the nanoessential oils, and also relatively adequate and acceptable protection time, nanoemulsions of E. globulus and probably M. piperita can be considered as good repellents. It is recommended to do more research on these nanoemulsion repellents, as they may be good alternatives to DEET.

Chemical Composition and Repellency Effect of Ferulago Angulate Plant Against Malaria Vector, Anopheles Stephensi

BackgroundMalaria is a health problem globally. There are several vector control measures. Using repellent to protect human from biting of vectors is one of the best ways. The aim of this study is to evaluate the efficacy of plant against biting of malaria vector, An.stephensi under laboratory conditions.MethodsChemical constituents of Ferulago angulate plant were determined by using gas chromatography-mass spectrometry. Efficacy and the protection time of plant were evaluated on Anopheles stephensi . ResultsA total of 40 compounds were identified in plant. Flourensiadiol (17.4%) dehydro-sabina keton (13.3%), β-maaliene (8.8%) was the highest in the plant. The mean assessed protection time and efficacy for plant was 60 and 100 minutes respectively. ED50 and ED90 values for this plant were 18.12 and 93.19 µl /cm2 respectively.ConclusionResults showed that plant has an acceptable protection time, therefore, this plant could be considered as a good herbal repellent against anopheles mosquitoes.