Manufacturing of renewable and biodegradable fiberboards from cake generated during biorefinery of sunflower whole plant in twin-screw extruder: Influence of thermo-pressing conditions

The starting material used in this study was a cake generated during thermo-mechanical fractionation of sunflower (Helianthus annuus L.) whole plant in a twin-screw extruder. It was slightly deoiled (16.7% of oil in dry matter). Composed mainly of fibers and proteins, it could be considered as a natural composite and was processed successfully into fiberboards by thermo-pressing. This study aimed to evaluate the influence of thermo-pressing conditions on mechanical and heat insulation properties of fiberboards manufactured from this cake. All fiberboards were cohesive, proteins and fibers acting respectively as binder and reinforcing fillers. Highest cake quantity (1000 mg/cm²) led to the highest breaking load (60.7 N) with a flexural strength at break quite low (2.9 MPa), lowest elastic modulus (216.6 MPa), and highest Charpy impact strength (6.5 kJ/m² for resilience). The increase of pressure applied during molding (from 320 to 360 kgf/cm²) led to an important increase of elastic modulus (from 352.6 to 728.6 MPa). Besides, fiberboard molded at 360 kgf/cm² was the most rigid of this study, and logically revealed the most important Shore D surface hardness (52.6°). Moreover, lowest molding time (60 s) led to the highest flexural strength at break (3.9 MPa). The low density of the fiberboards (less than 0.97) involved promising heat insulation properties. Indeed, thermal conductivity of fiberboards at 25 °C was low (from 103.5 to 135.7 mW/m K), and decreased with the increase of thickness. According to their mechanical and heat insulation properties, fiberboards would be potentially usable as inter-layer sheets for pallets, for the manufacture of biodegradable containers (composters, crates for vegetable gardening) by assembly of fiberboards, or for their heat insulation properties in building industry. Moreover, thermo-pressing was not only a molding operation. It also improved the oil extraction efficiency as a part of residual oil was expressed from cake during molding, and total oil yield reached 79.3% with a pressure applied of 360 kgf/cm²

Professionalizing the Everyday

When I think of tutors’ professionalization, I inevitably consider the texts I encourage tutors to read — not just tutor training manuals but also the theory and research that shape my understanding of our field. One such text that I’ve recently adopted for a new tutor training course is The Everyday Writing Center: A Community of Practice by Anne Geller, Michele Eodice, Frankie Condon, Meg Carroll and Elizabeth Boquet. Although I find this to be one of the most progressive writing center texts in our scholarly canon, it’s likely not on many tutors’ reading lists because it was written ostensibly for writing center administrators. Despite its title, this book’s insights into writing center leadership are not confined to the everyday nuts and bolts of running a center but are also valuable for tutors.University Writing Cente

New thermal insulation fiberboards from cake generated during biorefinery of sunflower whole plant in a twin-screw extruder

The objective of this study was to manufacture new thermal insulation fiberboards by thermo-pressing. The starting material was a slightly deoiled cake (17.6% oil content), generated during the biorefinery of sunflower (Helianthus annuus L.) whole plant in a co-rotating (Clextral BC 45, France) twin-screw extruder. All fiberboards produced were cohesive mixtures of proteins and lignocellulosic fibers, acting respectively as binder and reinforcing fillers in what could be considered as a natural composite. The molding experiments were conducted using a 400 ton capacity heated hydraulic press (Pinette Emidecau Industries, France). The influence of molding conditions on board density, mechanical properties and heat insulation properties was examined. Molding conditions included mold temperature (140-200°C), pressure applied (150-250 kgf/cm²) and molding time (40-76 s), and these greatly affected board density and thus the mechanical and heat insulation properties. Board density increased with increasingly extreme molding conditions, rising from 500 to 858 kg/m³. The mechanical properties increased at the same time (from 52 to 660 kPa for flexural strength at break, from 5.9 to 49.4 MPa for elastic modulus, from 0.5 to 7.7 kJ/m² for Charpy impact strength, and from 19.2 to 47.1° for Shore D surface hardness). Conversely, heat insulation properties improved with decreasing board density, and the lowest thermal conductivity (88.5 mW/m K at 25°C) was obtained with the least dense fiberboard. The latter was produced with a 140°C mold temperature, a 150 kgf/cm² pressure applied and a 40 s molding time. A medium mold temperature (160°C) was needed to obtain a good compromise between mechanical properties (272 kPa for flexural strength at break, 26.3 MPa for elastic modulus, 3.2 kJ/m² for Charpy impact strength, and 37.3° for Shore D surface hardness), and heat insulation properties (99.5 mW/m K for thermal conductivity).The corresponding board density was medium (687 kg/m³). Because of their promising heat insulation properties, these new fiberboards could be positioned on walls and ceilings for thermal insulation of buildings. The bulk cake also revealed very low thermal conductivity properties (only 65.6 mW/m K at 25°C) due to its very low bulk density (204 kg/m³). It could be used as loose fill in the attics of houses

(Un)Complicating Planning and Revising: Metacognition and Problem-Based Tutoring

Why do clients struggle with creating rhetorical plans and globally revising their texts, and how can peer tutors help clients cultivate effective planning and revision practices? Problems with planning and revising differ depending upon the student and the task. Nevertheless, many clients may struggle because they don’t view writing as a problem-solving process that involves addressing a particular audience, selecting and narrowing not only a “topic” but a thesis and support, establishing a purpose for the text, and creating a persona. Instead, clients come to writing with “ideas” for what they want to write about and begin producing text as soon as they feel they have “something to say.” Because clients have paid scant attention to audience, purpose, or persona, as their resulting products show, they have no starting point from which to review how or if their texts have successfully addressed an audience, achieved a purpose, or created an ethos.University Writing Cente

Twin-screw extrusion impact on natural fibre morphology and material properties in poly(lactic acid) based biocomposites

Natural fibres from miscanthus and bamboo were added to poly(lactic acid) by twin-screw extrusion. The influence of extruder screw speed and of total feeding rate was studied first on fibre morphology and then on mechanical and thermal properties of injected biocomposites. Increasing the screw speed from 100 to 300 rpm such as increasing the feeding rate in the same time up to 40 kg/h helped to preserve fibre length. Indeed, if shear rate was increased with higher screw speeds, residence time in the extruder and blend viscosity were reduced. However, such conditions doubled electrical energy spent by produced matter weight without significant effect on material properties. The comparison of four bamboo grades with various fibre sizes enlightened that fibre breakages were more consequent when longer fibres were added in the extruder. Longer fibres were beneficial for material mechanical properties by increasing flexural strength, while short fibres restrained material deformation under heat by promoting crystallinity and hindering more chain mobility

UA68/6/2 Eulogy on Dr. Kinnaman

Part of a chapel presentation by members of the Congress Debating Club regarding the history of WKU and it\u27s founding faculty. This portion was given by Evon Howell regarding A.J. Kinnaman who taught at WKU from 1906 to 1926. Kinnaman died in 1928

Neural Processing of Respiratory Sensations when Breathing Becomes More Difficult and Unpleasant

The accurate perception of respiratory sensations is important for the successful management and treatment of respiratory diseases. Previous studies demonstrated that external stimuli such as affective pictures and distracting films can impact the perception and neural processing of respiratory sensations. This study examined the neural processing of respiratory sensations when breathing as an internal stimulus is manipulated and becomes more difficult and unpleasant. Sustained breathing through an inspiratory resistive load was used to increase perceived breathing difficulty in 12 female individuals without respiratory disease. Using high-density EEG, respiratory-related evoked potentials (RREP) to short inspiratory occlusions were recorded at early versus late time points of sustained loaded breathing. Ratings of perceived intensity and unpleasantness of breathing difficulty showed an increase from early to late time points of loaded breathing (p < 0.01 and p < 0.05, respectively). This was paralleled by significant increases in the magnitudes of RREP components N1, P2, and P3 (p < 0.01, p < 0.05, and p < 0.05, respectively). The present results demonstrate increases in the neural processing of respiratory sensations when breathing becomes more difficult and unpleasant. This might reflect a protective neural mechanism allowing effective response behavior when air supply is at risk

The Northwest Arctic institute: an indigenous approach to prevention

Master's Project (M.A.) University of Alaska Fairbanks, 2016This paper will cover concepts of leadership in Indigenous contexts, Indigenous community development strategies, and Indigenous community healing and wellness, as they apply to the history and framework of the Northwest Arctic Institute (NWAI) program. The NWAI is a weeklong culturally based prevention program designed for Alaska Native peoples. The program incorporates Indigenous knowledge and pedagogy into the sharing of core teachings about resilience, adaptation, and cultural identity. It covers the impacts of rapid social, cultural, and political changes on the lives of Alaska Native peoples. The NWAI is for adults interested in furthering their own personal healing and in working on wellness within their families and communities. This paper explains an Indigenous approach to healing and the theoretical framework for supporting community level capacity building models among Alaska Native peoples. The paper also describes the NWAI planning process and methodology. In addition to the paper, which will meet completion requirements for the Masters in Rural Development at the University of Alaska Fairbanks, I will co-produce a documentary film on the NWAI to share our experience with the intention of raising awareness, fostering conversation, and inspiring others to action. The analysis and descriptions are based on the my life experience as an Alaska Native leader. I have served Indigenous communities for twenty years in roles spanning ten unique capacities, including education administrator, tribal administrator, tribal chief, national tribal non-profit executive director, for-profit Alaska Native owned corporate chief executive officer, tribal renewable energy manager, tribal wellness manager, and as a board member to regional, national, and international Indigenous organizations. The theoretical framework for leadership selection is derived from my work in developing, planning, and leading facilitation of the Northwest Arctic Institute, which was based on Indigenous youth leadership development and prevention experience at the local, national, and international levels. This history is covered within the Introduction and Program History sections

A new approach in the enhancement of student-law enforcement relations on college campuses : a case study of the University of Massachusetts.

This study examines factors in achieving a more nurturing and secure environment for minority students at the University of Massachusetts at Amherst. The study probes: (1) The existing issues and problems minority students face with on-campus police officers at the University of Massachusetts. (2) The role of higher administrators (chancellor, provost, deans) in dealing with these problems, and student and officer perceptions of the administrators\u27 commitment toward resolving them (3) The issues higher administration will encounter while creating a better relationship between minority students and law enforcement officers. (4) The feelings, perceptions and views held by students and officers and how these may affect their communication and interactions. The researcher found mutual dissatisfaction in the relationships between minority students and on-campus police officers. Evidence of this poor relationship is seen in past incidents involving minority students and police. Through protests and other unpleasant encounters with minority students, the police have gained insight into the feelings that exist between them and students. Generally, most minority students believe that the ill feelings between the two groups have affected the quality and character of the service they receive from police. An example of this can be seen in accusations of high rates of car stoppage of minority students, in particular African-American male students. This issue is not new to college campuses, rather it is an escalating phenomenon that embraces relations between the minority community and police in society at large. Data provide administrators with a deeper insight into the issues involved. These issues include stereotyping and a lack of understanding about each other\u27s roles. This information is critically needed, especially in light of the fact that there is no published research on this issue. This study provides first-of-a-kind information. This research involved the two groups (minority students and police officers) in sharing their perceptions and ideas. Understanding their feelings is an important aspect of this study. The researcher distinguished between feelings and theory through methodologies of data collection: (1) direct observation, (2) informal open-ended interviews, and (3) examination of University documents

Thermo-mechanical behaviour of the raffinate resulting from the aqueous extraction of sunflower whole plant in twin-screw extruder: manufacturing of biodegradable agromaterials by thermo-pressing

Biorefinery of sunflower whole plant can be realized using a twin-screw extruder. Thermo-mechanical fractionation and aqueous extraction are conducted simultaneously. A filter section is outfitted along the barrel to collect continuously an extract and a raffinate (cake meal). Oil yield obtained is 53%. Proteins are partly extracted at the same time, just as pectins and hemicelluloses. Protein yield is 46%. Cake meal is relatively moist (66% for the moisture content). It is first dried to make easier its conservation. It is largely composed of lignocellulosic fibres (59% of the dry matter) from depithed stalk. Lipid content is 13% of the dry matter or 35% of the oil in whole plant. Protein content is 7% of the dry matter or 45% of the proteins in whole plant. DSC measurements indicate that denaturation of proteins is almost complete in the cake meal. DMTA spectrum of its milled powder reveals a significant peak at high temperature (between 175 and 200°C). As already observed with industrial sunflower cake meal, it can be associated with the glass transition of proteins. As a mixture of fibres and proteins, the cake meal can be considered as a natural composite. It is successfully processed into biodegradable and value-added agromaterials by thermo-pressing. As for DMTA analysis, the glass transition of proteins in the cake meal is also observed with PVT analysis at around 180°C. It makes easier the choice of the best thermo-pressing conditions to produce panels with higher mechanical properties in bending. These properties increase simultaneously with temperature, pressure and time chosen for molding operation. The highest flexural strength at break (11.5 MPa) and the highest elastic modulus (2.22 GPa) are obtained for the next molding conditions: 200°C and 320 kgf/cm2 during 60 s. Drop angle measurements show that the corresponding panel is also the most resistant to water. No significant transition is observed inside this panel above 0°C and until 200°C with DMTA analysis. Proteins ensure the agromaterial cohesion without any phase change in this temperature range, and fibres entanglement also acts like reinforcement. This panel could be used as inter-layer sheets for pallets or for the manufacturing of biodegradable containers (composters, crates for vegetable gardening) by assembly of panels