Oil-based Agent Research Articles

Reaction dynamics and early-time behaviour of chemical decontamination

Abstract When a hazardous chemical soaks into a porous material such as a concrete floor, it can be difficult to remove. One approach is chemical decontamination, where a cleanser is added to react with and neutralise the contaminating agent. The goal of this paper is to investigate the reaction dynamics and the factors that affect the efficacy of the decontamination procedure. We consider a one-dimensional porous medium initially saturated with an oil-based agent. An aqueous cleanser is applied at the surface, so the two chemicals are immiscible and a boundary forms between them. A neutralising reaction takes place at this boundary in which cleanser and agent are consumed and reaction products are created. This is a Stefan problem, and the boundary between the cleanser and agent moves as the reaction proceeds. Reaction products formed at the interface may dissolve in one or both liquids. This may temporarily prevent cleanser and/or agent from reaching the reaction site, so diffusion of the chemical species, in particular the diffusion of product from the interface, plays a key role. The scenario described above was considered previously by Dalwadi et al. (2017, Mathematical modelling of chemical agent removal by reaction with an immiscible cleanser. SIAM J. Appl. Math., 77, 1937–1961) in the limit where the depth of the porous medium is large compared to the length scale over which concentrations vary inside the medium. Here, we present results that are valid for any ratio between these length scales and an analysis of agent removal times for various dimensionless parameter regimes. We also highlight the emergence of a boundary layer associated with diffusion in the oil phase for early times, where the thickness of the boundary layer is directly proportional to the square root of the time variable.

Crude palm oil as a bioadditive in polypropylene blown film

Growing public concern about environment and potential risks to health in the polymer and plasticizer industry promises to increase the market for a safer alternative plasticizer such as a vegetable oil-based agent. The purpose of this study was to investigate the potential of crude palm oil as a bio-additive in polypropylene blown films. The polypropylene was blended with 1%, 3%, and 5% dosages of CPO using a twin screw extruder. The extruded samples were blown using the blown thin film technique. Mechanical, physical, and morphological properties were characterized. Modifying polypropylene with CPO showed good enhancement in the mechanical properties of the polypropylene. Tensile strength, elongation at break, impact strength, and tear strength all increased. The scanning electron microscopy photographs of the CPO-modified PP clearly supported the results from the mechanical strength tests. The presence of CPO in the PP matrices decreased the density and increased the melt flow rate. These findings contribute new knowledge to the additives area and give important implications for designing and manufacturing polymer packaging materials.

CRUDE PALM OIL AS A BIOADDITIVE IN POLYPROPYLENE BLOWN FILMS

Growing public concern about environment and potential risks to health in the polymer and plasticizer industry promises to increase the market for a safer alternative plasticizer such as a vegetable oil-based agent. The purpose of this study was to investigate the potential of crude palm oil as a bio-additive in polypropylene blown films. The polypropylene was blended with 1%, 3%, and 5% dosages of CPO using a twin screw extruder. The extruded samples were blown using the blown thin film technique. Mechanical, physical, and morphological properties were characterized. Modifying polypropylene with CPO showed good enhancement in the mechanical properties of the polypropylene. Tensile strength, elongation at break, impact strength, and tear strength all increased. The scanning electron microscopy photographs of the CPO-modified PP clearly supported the results from the mechanical strength tests. The presence of CPO in the PP matrices decreased the density and increased the melt flow rate. These findings contribute new knowledge to the additives area and give important implications for designing and manufacturing polymer packaging materials.

Evaluation of Time Required for Water-Only Decontamination of an Oil-Based Agent

The objective was to evaluate the time to decontaminate an area of skin exposed to an oil-based agent using a water-only decontamination protocol. A fluorescent mock chemical/biological agent was created. Each of 20 subjects had his/her forearm sprayed with the agent. Each subject placed his/her arm under a decontamination shower, which provided water at a pressure of 60-70 psi and 35 degrees C. After 30 sec a black light was used by three evaluators to determine whether the agent was removed. The process of 30 sec decontamination and re-evaluation was repeated for a total of 5 min. The primary endpoint was proportion decontaminated over time. After 90 sec, 100% of subjects were decontaminated. Whereas the data suggest the possibility of rapid water-only decontamination, the applicability of this data in current form is doubtful, but provides a model as a basis for future study.

387: Evaluation of Time Required for Water-Only Topical Decontamination of an Oil-Based Agent

The objective was to evaluate the time required to decontaminate an area of human skin exposed to an oil-based agent using a water-only decontamination protocol based on consensus expert opinion, as this has not been systematically studied.

Pregnancy Outcomes after Fallopian Tube Recanalization: Oil-based versus Water-soluble Contrast Agents

To determine the pregnancy outcomes in patients undergoing fallopian tube recanalization (FTR) with use of oil-based versus water-soluble contrast agents. Ninety-three patients with unilateral or bilateral proximal tubal occlusion confirmed by hysterosalpingography or laparoscopy underwent FTR with use of water-soluble contrast material alone (n = 50) or also had an oil-based agent injected into each tube after recanalization (n = 43). Pregnancy rates and outcomes of the two groups were studied retrospectively. With respect to differences between groups, only the body mass index proved to be a significant predictor (oil, 28.4; water, 24.7; P =.008). Mean age, duration of infertility, type of infertility, and initial diagnosis were comparable. There was a weak trend toward a higher pregnancy rate in the oil-based contrast material group, but it was not significant (P =.64). The average time to pregnancy was 4.4 months with use of oil-based contrast material, compared to 7.7 months with use of only water-soluble contrast material (P =.03). The use of an oil-based agent had little effect on the rate of conception, but time to conception was reduced by more than 3 months.

Cervical myelography of nerve root avulsion injuries using water-soluble contrast media.

Eight cases of cervical nerve root avulsion injury are presented which were investigated by cervical myelography using a water-soluble contrast medium. The previous literature describes the appearances of this lesion using an oil-based agent and has resulted in emphasis being placed on looking for a traumatic meningocele rather than an abnormality of the roots themselves. The excellent definition of the nerve rootlets and axillary pouch that are obtained with a water-soluble contrast medium resulted in more root lesions per patient being detected than with an oil-based medium. There was complete correlation with the surgical findings at all but one root level explored. The appearances of root avulsion injuries and the advantages of using a water-soluble contrast medium are discussed.