Cellulose solutions in aqueous hydroxide bases

Cellulose is a renewable and widely available carbohydrate polymer whose utility for mankind only increases as we move towards a circular bioeconomy. Unlike most plastics or metals, it cannot be melted, and therefore, solution processing is important. The dissolution of cellulose is, however, not trivial, and traditional industrial methods must derivatize it in order to dissolve it adequately. Today, a number of direct solvents have been developed with considerable variation in both the structure of the solvent and the mechanism through which dissolution occurs. Despite this, one solvent that was reported as early as the 1920s still holds interest: cold aqueous NaOH solutions. Since the main processes in the pulp and paper industry are water-based, and NaOH is one of the main chemicals used, it is easy to see the attraction behind this solvent. The dissolution capacity and solution properties are however poor and must be improved. In order to design a solvent, the interactions between cellulose and the solvent as well as the interactions between cellulose molecules needs to be understood. Therefore, the purpose of this thesis has been to improve understanding for interactions governing cellulose dissolution and behaviour in NaOH(aq) and other aqueous solutions of hydroxide bases. In order to achieve this, cellulose dissolution at low temperatures in an aqueous solution of NaOH, combined with selected quatenary ammonium hydroxide bases, tetramethylammonium hydroxide (TMAH) and benzyltrimethylammonium hydroxide (Triton B), as well as urea, have been inves- tigated. The impact of different solvent combinations on the maximum dissolution capacity of cellulose and the rheology of the solutions were also investigated. The structure of the solvents was studied using spectroscopic and calorimetric methods. It was found that by combining hydroxide bases in an aqueous solution, the dissolution capacity and stability of the solution was improved and the effect was comparable to the addition of urea. The resulting solution properties depended on the base pair employed, probably due to a difference in contribution of hydrogen bonding versus van der Waals interactions, which in turn determines such properties as the temperature stability of the solution

Abraham: First Patriarch, First Prophet: Genesis 12-23 as Motive and Model for the Hebrew Prophetic Voice

Swensson claims not only that Abraham is the first prophet to appear in the Hebrew Bible, but also that his intimate, friendly relationship with God is the perfect model for the relationship between humanity and divinity. Swensson identifies four markers that differentiate Abraham\u27s relationship with God from all other human-divine relationships previously available in the text: 1) a reciprocal call between the human and the divine, 2) the gradual revelation of God\u27s will, 3) Abraham\u27s direct and honest communication with God, 4) an anomic, deviant existence that shows Abraham\u27s complete devotion to the will of God. The reciprocal call between Abraham and Yahweh can be seen in Genesis 12 when Yahweh calls to Abraham with a command and a promise. Abraham, however, is also frequently described as invoking God. These two call upon and respond to each other. Additionally, God\u27s call to Abraham is not immediately clear, but is revealed over time. This is significant because it means that God does not call Abraham and abandon him, rather they walk together, and so the call of God is constantly changing, calling humanity forward to a better future. This begins to show a more intimate relationship between Abraham and God than had previously existed in the text. Finally, Abraham\u27s prophetic role, and the relationship with God that it implies, is solidified in that he is required to live outside of the normal bounds of society. This is made most obviously clear when he is asked to sacrifice his son. God must know that Abraham is willing to abandon the order proclaimed by society and do away with his own ego to trust wholly in God. Finally, Abraham\u27s role is solidified, Swensson argues, because he is the father of all the nations, and all the future prophets and believers are his descendants

The Problem of Death and Dying in Contemporary America: A Thanatological Diagnosis and the Case for Religion

Swensson lays out the many obstacles that have resulted in twenty-first century Americans being unable to accept death. By examining the history of major social changes in the West, such as the Protestant reformation, as well as the current ways of dealing with death and dying, Swensson posits that improving how society deals with death and the dying must be aided by theology. Currently, social, political, and religious changes in the West have led to a general sense of loneliness, meaninglessness, and helplessness that are only intensified when a person faces death. Unfortunately, the current environment in which most people greet death makes it difficult for them to care for the emotional and spiritual needs of the dying or their families. This can generally be attributed to the fact that hospitals attempt to forestall death at any costs, and in so doing frequently strip people of their dignity. While hospices attempt to counteract this objectification, the frequent close quarters and intimate witnessing of physical deterioration in them make it difficult for that goal to be fulfilled. Swensson argues that thanatology (the sociological study of death and dying,) is valuable and that efforts should be made to make a more respectful dying process. She concludes that this will only be able to come to fruition when theology is welcomed in to play a real part in the way society approaches death and dying

Dissolution of cellulose in aqueous hydroxide base solvents

As we move towards a circular bioeconomy, new and advanced materials based on cellulose are constantly developed. Unlike most plastics or metals, cellulose cannot be melted, and therefore dissolution is an important tool for processing of cellulose but also for analytical purposes. There is, however, both a knowledge gap in understanding the mechanisms behind dissolution as well as a continued search for new and improved solvents.Aqueous solutions of hydroxide bases are a group of solvents with considerable variation in both dissolution capacity and stability of cellulose solutions, and their properties need to be improved to be useful solvents. Despite this, they are interesting because they have the potential to be cheap and non-toxic, depending on the base of choice. Therefore, the purpose of this thesis has been to further understand the interactions governing cellulose dissolution and properties in aqueous solutions of hydroxide bases, so that in the future, new and improved solvents can be designed. In order to achieve this, cellulose dissolution at low temperatures in aqueous solutions of NaOH and selected quaternary ammonium hydroxide bases has been investigated. The effect of combining NaOH with a quaternary ammonium hydroxide was also investigated, along with the influence of the commonly used additive urea.Results based on light scattering measurements revealed that dissolution in NaOH(aq) is poor, with relatively large aggregates present already at very dilute concentrations and a fraction of undissolved cellulose always present. Upon comparing NaOH to more hydrophobic quaternary ammonium hydroxides, it was observed that the dissolution capacity of the bases increased with increasing hydrophobicity of the cation, alongside their ability to act as hydrogen bond acceptors. Rheology measurements showed that compared to pure NaOH(aq) or pure tetramethylammonium hydroxide (TMAH)(aq), combining NaOH with TMAH improved the stability of the solutions over time and against increasing temperature. It was therefore proved that combining bases can have a similar effect as an additive, but the results were highly dependent on the base pair employed and indicated that both bases need to be able to dissolve cellulose on their own, within the same temperature interval and be miscible with each other in order to improve solution properties

Defense Drafts Aluminium

S. J. Swensson, secretary, Aluminium Wares Association, tells of the industry and defens

Underlying mechanisms behind nitrous oxide emissions in oilseed radish, Raphanus sativus var. oleiformis, and Phacelia tanacetifolia

Greenhouse gases are a driving force of climate change and the annual greenhouse gas emissions were higher between 2010-2019 than any other time in human history (Skea et. al. 2022). Cover crops are used to mitigate the effect of climate change, but recent studies indicate that the use of the cover crop oilseed radish results in significantly larger emissions of nitrous oxide (N2O) compared to other cover crops (Dörsch et. al. 2022; Müller Júnior et. al. 2019; Olofsson and Ernfors 2022; Thomas et. al. 2017). Results from Olofsson and Ernfors (2022) study showed that Raphanus sativus var oleiformis (OR) causes significantly higher emission of N2O compared to Phacelia tanacetifolia (PH) even though the quality and quantity were similar. The hypothesis in this study was that the glucosinolates in OR provides a carbon source for denitrifying bacteria, thus causing a significantly higher N2O emission compared to PH. The hypothesis was tested in a laboratory setting during 32 days of gas measurement with plant material of OR and PH incubated with and without added glucose. Surprisingly, aboveground plant material of PH showed highest emissions throughout the study. The result of this study could not confirm the hypothesis since added glucose did not affect the N2O emission. In further studies, it is recommended to increase the number of replicates and optimize the methodology to be able to draw any conclusions