INFLUENCE OF VARIOUS FACTORS ON THE CONTENT OF THE MASS FRACTION OF THE INSOLUBLE PART IN HOOKAH TOBACCO

Исследовано влияние влажности табачного сырья, его сортотипа, количества в рецептуре на содержание массовой доли нерастворимой части в табаке для кальяна. Объектом исследования были образцы кальянных смесей разных торговых марок, приобретенных в торговой сети Краснодара и составленных в лабораторных условиях Всероссийского научно-исследовательского института табака, махорки и табачных изделий. Образцы кальянной смеси изготавливали по единой для всех образцов рецептуре и технологической схеме: увлажнение, резка, выдерживание в соусе с нагревом, охлаждение. Влажность и количество табачного сырья в рецептуре варьировали. Методом количественного определения содержания табака в готовом продукте, основанном на способности части ингредиентов кальянных смесей растворяться в воде, определяли массовую долю нерастворимой части. Установлено, что содержание массовой доли нерастворимой части в табаке для кальяна различных торговых марок, приобретенном в торговой сети Краснодара, составляет 5,2–8,8%. Сортотип табачного сырья, его химический состав и добавленный в смесь ароматизатор не влияют на содержание массовой доли нерастворимой части в табаке для кальяна. Содержание массовой доли нерастворимой части табака для кальяна в значительной степени зависит от влажности и количества табачного сырья, используемого в рецептуре. Увеличение влажности исходного сырья приводит к уменьшению массовой доли нерастворимой части в смеси для кальяна: при влажности сырья 10% массовая доля нерастворимой части 6,8%; при влажности того же сырья 16% массовая доля нерастворимой части 5,2%. The influence of humidity of tobacco raw materials, its variety type, and the amount in the recipe on the content of the mass fraction of the insoluble part in hookah tobacco has been studied. Samples of hookah mixes of various brands purchased in the retail network of Krasnodarand compiled in the laboratory of the All-Russian Scientific Research Institute of Tobacco, shag and Tobacco Products were the object of research. Samples of hookah mix were made according to the same formulation and technological scheme for all samples: humidification, cutting, keeping in a sauce with heating, cooling. The humidity and amount of tobacco raw materials in the formulation varied. By quantifying the content of tobacco in the finished product, based on the ability of some of the ingredients of hookah mixtures to dissolve in water, the content of the mass fraction of the insoluble part was determined. It is established that the content of the mass fraction of the insoluble part in hookah tobacco of various brands purchased in the retail network of Krasnodar is 5,2–8,8%. The variety type of tobacco raw materials, its chemical composition and added flavor to the mixture do not affect the content of the mass fraction of the insoluble part in hookah tobacco. The content of the mass fraction of the insoluble part of tobacco for hookah largely depends on the humidity and the amount of tobacco raw materials used in the formulation. The increase of humidity of raw materials leads to a decrease of the mass fraction of the insoluble part of hookah tobacco: if moisture content of raw materials 10% mass fraction of the insoluble portion of 6,8%; the humidity of the same raw materials 16%, the mass fraction of the insoluble portion of 5,2%.

Linear Viscoelasticity and Flow of Self-Assembled Vitrimers: The Case of a Polyethylene/dioxaborolane System

For vitrimer systems obtained by dynamic cross-linking of polymer chains, incompatibility effects between the cross-links and polymer backbone can lead to microphase separation, resulting in a network made of cross-linked aggregates. Additionally, when there is a wide distribution of the number of cross-links per chain, macrophase separation can occur. Here, we investigate the linear viscoelasticity and flow of a polyethylene (PE) vitrimer that has cross-linkable dioxaborolane maleimide grafts, which aggregate into a hierarchical nanostructure. To elucidate the role of self-assembly, noncross-linked graft functionalized PE was first studied. It had a terminal relaxation time that was orders of magnitude larger than both neat PE and partially peroxide cross-linked PE. When dioxaborolane cross-linker was added to form the vitrimer, the resulting material could not achieve terminal relaxation within 8 hr. The graft-poor soluble and graft-rich insoluble portions of the PE vitrimer were then isolated and characterized. The soluble portion expressed similar flow behavior as neat PE, while the insoluble portion – which is a network of cross-linked aggregates – relaxed very little over 8 hr. When the insoluble and soluble portions were blended, the rheological behavior of the original vitrimer was basically recovered, showing that the soluble portion acts as a lubricant. When the insoluble portion was blended with neat PE, the material relaxed much more stress, but still did not reach steady-state flow within 8 hr. When high stresses were applied, however, PE vitrimer flowed. Nonlinear rheology experiments revealed melt fracture at high strains and suggested that flow is enabled by rapid healing, which follows fracture events. The presence of macroscopic phase separation facilitated flow.

Linear Viscoelasticity and Flow of Self-Assembled Vitrimers: The Case of a Polyethylene/dioxaborolane System

For vitrimer systems obtained by dynamic cross-linking of polymer chains, incompatibility effects between the cross-links and polymer backbone can lead to microphase separation, resulting in a network made of cross-linked aggregates. Additionally, when there is a wide distribution of the number of cross-links per chain, macrophase separation can occur. Here, we investigate the linear viscoelasticity and flow of a polyethylene (PE) vitrimer that has cross-linkable dioxaborolane maleimide grafts, which aggregate into a hierarchical nanostructure. To elucidate the role of self-assembly, noncross-linked graft functionalized PE was first studied. It had a terminal relaxation time that was orders of magnitude larger than both neat PE and partially peroxide cross-linked PE. When dioxaborolane cross-linker was added to form the vitrimer, the resulting material could not achieve terminal relaxation within 8 hr. The graft-poor soluble and graft-rich insoluble portions of the PE vitrimer were then isolated and characterized. The soluble portion expressed similar flow behavior as neat PE, while the insoluble portion – which is a network of cross-linked aggregates – relaxed very little over 8 hr. When the insoluble and soluble portions were blended, the rheological behavior of the original vitrimer was basically recovered, showing that the soluble portion acts as a lubricant. When the insoluble portion was blended with neat PE, the material relaxed much more stress, but still did not reach steady-state flow within 8 hr. When high stresses were applied, however, PE vitrimer flowed. Nonlinear rheology experiments revealed melt fracture at high strains and suggested that flow is enabled by rapid healing, which follows fracture events. The presence of macroscopic phase separation facilitated flow.

Linear Viscoelasticity and Flow of Self-Assembled Vitrimers: The Case of a Polyethylene/dioxaborolane System

For vitrimer systems obtained by dynamic cross-linking of polymer chains, incompatibility effects between the cross-links and polymer backbone can lead to microphase separation, resulting in a network made of cross-linked aggregates. Additionally, when there is a wide distribution of the number of cross-links per chain, macrophase separation can occur. Here, we investigate the linear viscoelasticity and flow of a polyethylene (PE) vitrimer that has cross-linkable dioxaborolane maleimide grafts, which aggregate into a hierarchical nanostructure. To elucidate the role of self-assembly, noncross-linked graft functionalized PE was first studied. It had a terminal relaxation time that was orders of magnitude larger than both neat PE and partially peroxide cross-linked PE. When dioxaborolane cross-linker was added to form the vitrimer, the resulting material could not achieve terminal relaxation within 8 hr. The graft-poor soluble and graft-rich insoluble portions of the PE vitrimer were then isolated and characterized. The soluble portion expressed similar flow behavior as neat PE, while the insoluble portion – which is a network of cross-linked aggregates – relaxed very little over 8 hr. When the insoluble and soluble portions were blended, the rheological behavior of the original vitrimer was basically recovered, showing that the soluble portion acts as a lubricant. When the insoluble portion was blended with neat PE, the material relaxed much more stress, but still did not reach steady-state flow within 8 hr. When high stresses were applied, however, PE vitrimer flowed. Nonlinear rheology experiments revealed melt fracture at high strains and suggested that flow is enabled by rapid healing, which follows fracture events. The presence of macroscopic phase separation facilitated flow.

Linear Viscoelasticity and Flow of Self-Assembled Vitrimers: The Case of a Polyethylene/dioxaborolane System

For vitrimer systems obtained by dynamic cross-linking of polymer chains, incompatibility effects between the cross-links and polymer backbone can lead to microphase separation, resulting in a network made of cross-linked aggregates. Additionally, when there is a wide distribution of the number of cross-links per chain, macrophase separation can occur. Here, we investigate the linear viscoelasticity and flow of a polyethylene (PE) vitrimer that has cross-linkable dioxaborolane maleimide grafts, which aggregate into a hierarchical nanostructure. To elucidate the role of self-assembly, noncross-linked graft functionalized PE was first studied. It had a terminal relaxation time that was orders of magnitude larger than both neat PE and partially peroxide cross-linked PE. When dioxaborolane cross-linker was added to form the vitrimer, the resulting material could not achieve terminal relaxation within 8 hr. The graft-poor soluble and graft-rich insoluble portions of the PE vitrimer were then isolated and characterized. The soluble portion expressed similar flow behavior as neat PE, while the insoluble portion – which is a network of cross-linked aggregates – relaxed very little over 8 hr. When the insoluble and soluble portions were blended, the rheological behavior of the original vitrimer was basically recovered, showing that the soluble portion acts as a lubricant. When the insoluble portion was blended with neat PE, the material relaxed much more stress, but still did not reach steady-state flow within 8 hr. When high stresses were applied, however, PE vitrimer flowed. Nonlinear rheology experiments revealed melt fracture at high strains and suggested that flow is enabled by rapid healing, which follows fracture events. The presence of macroscopic phase separation facilitated flow.

Exhaust Emissions Characterization of a Turbocharged 2-Stroke Tier 0+ Locomotive Engine: NOx, Particulate Matter and Soluble Organic Fraction Composition

This study presents a detailed exhaust emission characterization of a 2-Stroke turbocharged line haul locomotive diesel engine fitted with an early-development Tier 0 + emissions kit. The objective of this work is to use emissions characterization to gain insight into engine operation and mechanisms of pollutant formation for this family of engine, and identify areas of potential future engine emissions improvement. Results show that at the notches tested (notches 3–8) the largest contributor to particulate matter (PM)mass is insolubles (mostly elemental carbon), but that the soluble component of PM, comprising 14–32% of PM, is also significant. Gas chromatography (GC) analysis of the soluble portion shows that it is composed of 55–77% oil-like C22–C30+ hydrocarbons, with the remainder being fuel-like C9–C21 hydrocarbons. The emissions characterization suggests that advancing combustion timing should be effective in reducing PM mass by reducing the insoluble portion (elemental carbon) of PM at all notches. NOx will likely increase, but the current level of NOx is sufficiently below Tier 0+ limits to allow a moderate increase. Reducing engine oil consumption should also reduce PM mass at all notches, although to a smaller degree than measures that reduce the insoluble portion of PM.

Exhaust Emissions Characterization of a Turbocharged 2-Stroke Tier 0+ Locomotive Engine: NOx, PM, SOF and SOF Composition

This study presents a detailed exhaust emission characterization of an EMD 2-Stroke turbocharged line haul locomotive diesel engine fitted with an early-development Tier 0+ emissions kit. The objective of this work is to use emissions characterization to gain insight into engine operation and mechanisms of pollutant formation for this family of engine, and identify areas of potential future engine emissions improvement. Results show that at the notches tested (notches 3–8) the largest contributor to PM mass is insolubles (mostly elemental carbon), but that the soluble component of PM, comprising 14–32% of PM, is also significant. GC-FID analysis of the soluble portion shows that it is composed of 55–77% oil-like C22-C30+ hydrocarbons, with the remainder being fuel-like C9-C21 hydrocarbons. The emissions characterization suggests that advancing combustion timing should be effective in reducing PM mass by reducing the insoluble portion (elemental carbon) of PM at all notches. NOx will likely increase, but the current level of NOx is sufficiently below Tier 0+ limits to allow a moderate increase. Reducing engine oil consumption should also reduce PM mass at all notches, although to a smaller degree than measures that reduce the insoluble portion of PM.

Studies of Mechanical Properties and Melting Behaviour of Foamed and Crosslinked LDPE/PP Blends

Foamed crosslinked specimens of LDPE/PP blends produced by RIM process were examined. A crosslinking system containing 2,5-dimethyl-2,5-di(tert.-butylperoxy)hexane as an initiator and hydroquinone as a coagent was used. Azodicarbonamide was applied as a foaming agent. The crosslinking degree was evaluated by insoluble portion of the blends. An improvement of the mechanical properties due to crosslinking mainly in the LDPE phase as well as crosslinking between polyethylene and polypropylene on their interface was observed. Melting behaviour of the blends studied by DSC shows that both the initiator and the coagent cause opposite effects on temperatures and enthalpies of melting.

Intramuscular collagen and serum hydroxyproline as related to implanted testosterone, dihydrotestosterone and estradiol-17 β in growing wethers

Relationships of implanted testosterone, dihydrotestosterone and estradiol-17 β to collagen degradation and intramuscular collagen concentration and stability were determined. Intramuscular collagen content, solubility and shrinkage temperature and serum hydroxyproline were analyzed in groups of six rams, wethers, and wethers implanted with various levels of testosterone or dihydrotestosterone (Exp. 1) and groups of 10 rams, wethers and wethers implanted with estradiol-17 β, dihydrotestosterone or a combination of (Exp.2). Intramuscular collagen content in both experiments was higher (P < .05) in muscles of rams than in muscles of wethers. Administration of the highest level of testosterone to wethers raised (P < .05) total and insoluble intramuscular collagen to concentrations noted in rams. Administration of the testosterone metabolite, dihydrotestosterone, to wethers had no effect on intramuscular collagen. Administration of estradiol-17 β to wethers tended to raise concentrations of intramuscular collagen so that they were no longer lower (P < .05) than those in rams. Collagen stability as measured by solubility and thermal shrinkage temperature did not differ among rams, wethers or implanted wethers (P < .05). Increases in collagen accretion due to hormone administration were observed to be the result of increases in the insoluble portion of the intramuscular collagen (P < .05).