Effects of Petroleum-Based Oils as Dispersing Aids on Physicochemical Characteristics of Magnetorheological Elastomers

This paper investigated the effects of petroleum-based oils (PBOs) as a dispersing aid on the physicochemical characteristics of natural rubber (NR)-based magnetorheological elastomers (MREs). The addition of PBOs was expected to overcome the low performance of magnetorheological (MR) elastomers due to their inhomogeneous dispersion and the mobility of magnetic particles within the elastomer matrix. The NR-based MREs were firstly fabricated by mixing the NR compounds homogeneously with different ratios of naphthenic oil (NO), light mineral oil (LMO), and paraffin oil (PO) to aromatic oil (AO), with weight percentage ratios of 100:0, 70:30, 50:50, and 30:70, respectively. From the obtained results, the ratios of NO mixed with low amounts of AO improved the material physicochemical characteristics, such as thermal properties. Meanwhile, LMO mixed the AO led to the best results for curing characteristics, microstructure observation, and magnetic properties of the MREs. We found that the LMO mixed with a high content of AO could provide good compatibility between the rubber molecular and magnetic particles due to similar chemical structures, which apparently enhance the physicochemical characteristics of MREs. In conclusion, the 30:70 ratio of LMO:AO is considered the preferable dispersing aid for MREs due to structural compounds present in the oil that enhance the physicochemical characteristics of the NR-based MREs.

A study of triangular membership function and multiple regressions to calculate the MSW compost index

The municipal solid waste compost consists of elements with a varied composition, including light and heavy metal elements. For MSW compost to act as a soil conditioner, and to ensure agricultural stakeholders to believe in its use for crops production, validation of elements is obligatory. The triangular membership function evaluates each element of a fuzzy set for both discrete and continuous values, and regression analysis estimates the relationship between values. In this paper, a triangular membership function (μf) is studied and used to characterize the effect of individual elements available in the compost sample. The characterization determines the variation in the composition of elements in the compost sample and accordingly calculates its scorei. Furthermore, a reinvestigation is done by applying multiple regression analysis, especially on heavy metals, to compare their composition with light mineral nutrients and other supplementary elements. A relationship between R=4.12 and R2=0.067498635 is derived to determine the predicted value and defines the composition of heavy metals as attributed to another mineral nutrients. Furthermore, a correlation (Co) is derived to find the performance of the compost sample todecide whether both light and supplementary mineral nutrients are capable of minimizing the effect of heavy metals. A gratuity score (Gsi) is added to each heavy metal depending on the correlation value to form a composti. The scorei=88.11 and composti = 9.12 obtained, was summated to derive Ci=97.23, stating that the increase in score value declares that the compost sample is mature enough to be used for agriculture and enhance crops productivity.

Licorice (Glycyrrhiza glabra (Linnaeus, 1753)) roots aqueous extract and some additives against Bactrocera zonata (Saunders, 1841) (Diptera: Tephritidae)

Peach fruit fly, Bactrocera zonata (Saunders, 1841) is a destructive polyphagous pest threatening the horticultural production in Egypt. Licorice, Glycyrrhiza glabra (Linnaeus, 1753) is a plant growing in Egypt and many other countries and famous for saponins groups that have insecticidal effect against broad spectrum of insect pests. In the present study, the insecticidal effect of licorice roots aqueous extract (LRAE), petroleum oil, KZ light mineral oil 96% (EC), water and an emulsion (1/4 L LRAE + ¼ L petroleum oil + ½ L KZ light oil 96% (EC)) treatments in a ratio 1 L: 29 L water were used in Matabi® sprayer of 30 L capacity against B. zonata pupae in sandy and clay soils. In sandy and clay soils LRAE reduced B. zonata population by 74.44% and 87.55% while petroleum oil, KZ light mineral oil 96% (EC) prevented flies emergence (100% reduction). Water treatment suppressed B. zonata population by 78.61% in sandy soil but caused 100% population reduction in clay soil. The emulsion reduced B. zonata population by 96.94% in sandy soil and 100% in clay soil. The best method for application of the emulsion was to spray as one target spray technique for eight seconds that was sufficient to obtain suitable coverage on soil with spray speed 1.2 km / hour. The persistence of the emulsion that highly reduced B. zonata larval populations was 3.5 and 4.5 days in sandy and clay soils, respectively. The flies emerged from B. zonata pupae treated with the emulsion neither feed nor move naturally. The histological studies showed that these flies suffered changes in the eyes, labellum, muscles and midgut tissues that were different from the emerged control treatment flies.

The Occurrences and Formation of Ladderback Ripples on Barchans Dunes of Najaf Dunes Field, Iraq, in Aeolian Environments

This paper concerns the study of ripples that occur on the windward of Barchan dunes from the dunes field of Najaf governorate, Iraq. These dunes consist mainly of sand sediments with variable sizes, including medium, fine, and very fine sands. Quartz represents the major light mineral in the Najaf Dunes sand. The prevailing wind direction in the study area is NW-SE. The major ripple crest series of every pattern are oriented perpendicular to the NW-SE wind direction, whereas imbricated ripple groups within the troughs of the preexisting ripples are created by the WSW-ENE wind trend. These ripples tend to be formed by shortened ripples that occupy the troughs of the prolonged series. All crests of the ladderback ripples are oriented at right angles to asymmetry ripples. The ladderback ripples were noticed from fine to very fine- grained sediments, which consist mainly of quartz. The wavelength of the ladderback ripples ranges from 2 – 4 cm, while they are 0.1 – 0.2 cm in height. The occurrence of ladderback ripples within an aeolian environment indicates a variety of wind directions, which influenced the arrangements of the crest ripples.

Rheological properties and flow behaviour of wax-stabilized water-in-oil emulsions

The objective of this study was to characterize the flow and rheological behaviour of model wax-stabilized water-in-oil (W/O) emulsions consisting of light mineral oil, paraffin wax and glycerol monooleate as the oil phase and water as the dispersed aqueous phase. An[sic] laboratory-scale benchtop flowloop system was used to explore the flow behaviour of the emulsions' oil phase (oil, paraffin wax and surfactant). The key contribution from this work was that the higher initial temperature gradient (40°C compared to 19°C) experienced by the rapidly-cooled oil led to more initial deposition on the flowloop inner wall. The rheological properties of W/O emulsions with different water cuts (10-50wt%) were also studied. Rotational, oscillatory rheology and creep compliance and recovery were characterized on emulsions aged up to 28 days. Overall, the results demonstrated that emulsion composition, and age could significantly influence an emulsion's flow behaviour and rheological properties.

Rheological properties and flow behaviour of wax-stabilized water-in-oil emulsions

The objective of this study was to characterize the flow and rheological behaviour of model wax-stabilized water-in-oil (W/O) emulsions consisting of light mineral oil, paraffin wax and glycerol monooleate as the oil phase and water as the dispersed aqueous phase. An[sic] laboratory-scale benchtop flowloop system was used to explore the flow behaviour of the emulsions' oil phase (oil, paraffin wax and surfactant). The key contribution from this work was that the higher initial temperature gradient (40°C compared to 19°C) experienced by the rapidly-cooled oil led to more initial deposition on the flowloop inner wall. The rheological properties of W/O emulsions with different water cuts (10-50wt%) were also studied. Rotational, oscillatory rheology and creep compliance and recovery were characterized on emulsions aged up to 28 days. Overall, the results demonstrated that emulsion composition, and age could significantly influence an emulsion's flow behaviour and rheological properties.

Relationships Between Fat Crystal Characteristics and Emulsion Stability in Water in Oil Systems

Investigations were made into the stabilization of water in oil emulsions using crystalline particles of paraffin wax and fully hydrogenated canola and cottonseed oils. A model system was studied to develop a methodology of study and provide a benchmark for a subsequent study of a real-world system. The model system involved the use of light mineral oil, purified water, paraffin wax and glycerol monooleate emulsifier. The wax was crystallized prior to and following emulsification. Prepared emulsion samples were monitored for sedimentation and flocculation behaviour. Measurements of coalescence were obtained by pulsed field gradient NMR. Formation of the solid crystalline wax phase following emulsification resulted in emulsions more stable to flocculation and coalescence than samples containing the same amount of wax crystallized prior to emulsification. Analysis of emulsion samples with polarized light microscopy showed the wax crystals were associated with the water droplet interfaces rather than dispersed freely within the continuous oil phase. Another investigation employed similar experimental protocols but incorporated food-grade materials. Two different solid fats were used, chosen for their differing polymorphic (crystal habit) behaviour. Solid crystals of canola stearine (ß-tending) and cottonseed stearine (ß-tending) were compared in their abilities to stabilize emulsions at levels of addition between 0 and 2%. Each type of fat was incorporated into the emulsion in a pre-crystallized state, or while melted and crystallized following emulsification. Cottonseed stearine was found to be in the ß polymorph when quickly crystallized following emulsification from 45⁰ to 5⁰C over 6 minutes. Further calorimetric and X-ray diffraction investigations revealed this crystallization behaviour was a result of a solid-state transformation via an imperfectly formed ß̕ intermediate. With respect to the post-crystallized emulsions, where the polymorphism of the two fats were both in the ß-form, the canola stearine provided better stabilization against coalescence than the cottonseed stearine. This observation coincided with a stronger energy of interfacial attachment for crystallized canola than for cottonseed as calculated from measurements of contact angle and interfacial tension. With the pre-crystallized system, incorporation of cottonseed stearine resulted in reduced sedimentation and coalescence compared to samples containing pre-crystallized canola stearine. This difference was attributed to the presence of fine shards of ß̕-form crystals. The system that imparted the highest degree of overall stability incorporated the use of canola stearine srystallized following emulsification.

Relationships Between Fat Crystal Characteristics and Emulsion Stability in Water in Oil Systems

Investigations were made into the stabilization of water in oil emulsions using crystalline particles of paraffin wax and fully hydrogenated canola and cottonseed oils. A model system was studied to develop a methodology of study and provide a benchmark for a subsequent study of a real-world system. The model system involved the use of light mineral oil, purified water, paraffin wax and glycerol monooleate emulsifier. The wax was crystallized prior to and following emulsification. Prepared emulsion samples were monitored for sedimentation and flocculation behaviour. Measurements of coalescence were obtained by pulsed field gradient NMR. Formation of the solid crystalline wax phase following emulsification resulted in emulsions more stable to flocculation and coalescence than samples containing the same amount of wax crystallized prior to emulsification. Analysis of emulsion samples with polarized light microscopy showed the wax crystals were associated with the water droplet interfaces rather than dispersed freely within the continuous oil phase. Another investigation employed similar experimental protocols but incorporated food-grade materials. Two different solid fats were used, chosen for their differing polymorphic (crystal habit) behaviour. Solid crystals of canola stearine (ß-tending) and cottonseed stearine (ß-tending) were compared in their abilities to stabilize emulsions at levels of addition between 0 and 2%. Each type of fat was incorporated into the emulsion in a pre-crystallized state, or while melted and crystallized following emulsification. Cottonseed stearine was found to be in the ß polymorph when quickly crystallized following emulsification from 45⁰ to 5⁰C over 6 minutes. Further calorimetric and X-ray diffraction investigations revealed this crystallization behaviour was a result of a solid-state transformation via an imperfectly formed ß̕ intermediate. With respect to the post-crystallized emulsions, where the polymorphism of the two fats were both in the ß-form, the canola stearine provided better stabilization against coalescence than the cottonseed stearine. This observation coincided with a stronger energy of interfacial attachment for crystallized canola than for cottonseed as calculated from measurements of contact angle and interfacial tension. With the pre-crystallized system, incorporation of cottonseed stearine resulted in reduced sedimentation and coalescence compared to samples containing pre-crystallized canola stearine. This difference was attributed to the presence of fine shards of ß̕-form crystals. The system that imparted the highest degree of overall stability incorporated the use of canola stearine srystallized following emulsification.