Fiber Products Research Articles

Optimisation of CFRP composite recycling process based on energy consumption, kinetic behaviour and thermal degradation mechanism of recycled carbon fibre

Abstract Pyrolysis is a thermo-chemical method to recover clean fibres from carbon fibre reinforced polymer (CFRP) composite waste under oxygen-free conditions. To ensure the recovery quality and economic efficiency of reclaimed fibres, thermal decomposition of CFRP needs to be guided by the kinetic analysis. This paper investigates the kinetic behaviour of CFRP thermal decomposition at temperatures of up to 800 °C. A thermo-gravimetric method is used to monitor the thermal decomposition of CFRP samples during the pyrolysis process. The activation energies (E) required for different conversion fractions (α) are evaluated based on five different kinetic models: four Arrhenius-type model-free methods (Friedman, OFW, KAS and Starink) and one curve fitting method (Coats-Redfern). Pyrolysis of CFRP composite wastes show that the process consists of two stages, where majority of the polymer matrix (55%) is removed in the first stage of reaction. During stage one and up to 425 °C, lower heating rates successfully lead to higher conversion fractions with lower activation energies. Moreover, by investigating physical characteristics of the recycled fibres using scanning electron microscopy (SEM) and conversion kinetics of the recycling process, it is shown that pyrolysis of the composite remains efficient until 425 °C and an oxidation process up to 550 °C is required to achieve high quality recycled carbon fibre (rCF) products. The outcomes of this research contribute to optimisation of process variables and development of highly efficient and cost effective CFRP recycling method using pyrolysis technique.

Windows for cdgas

We study a Fourier-Mukai kernel associated to a GIT wall-crossing for arbitrarily singular (not necessarily reduced or irreducible) affine varieties over any field. This kernel is closely related to a derived fiber product diagram for the wall-crossing and simple to understand from the viewpoint of commutative differential graded algebras. However, from the perspective of algebraic varieties, the kernel can be quite complicated, corresponding to a complex with multiple homology sheaves. Under mild assumptions in the Calabi-Yau case, we prove that this kernel provides an equivalence between the category of perfect complexes on the two GIT quotients. More generally, we obtain semi-orthogonal decompositions which show that these categories differ by a certain number of copies of the derived category of the derived fixed locus. The derived equivalence for the Mukai flop is recovered as a very special case.

Some remarks on Prüfer rings with zero-divisors

Let A be the fiber product R × T B , where B → T is a surjective ring homomorphism with regular kernel and R ⊆ T is a ring extension where T is an overring of R . In this paper we provide a characterization of when A has distinguished Prüfer-like properties and new constructions of Prüfer rings with zero-divisors. Furthermore we give examples of homomorphic images of Prüfer rings that are Prüfer without assuming that the kernel of the surjection is regular. Finally we provide some remarks on the ideal theory of pre-Prüfer rings.

Bundles with Non-multiplicative Â-Genus and Spaces of Metrics with Lower Curvature Bounds

Abstract We construct smooth bundles with base and fiber products of two spheres whose total spaces have nonvanishing $\hat{A}$-genus. We then use these bundles to locate nontrivial rational homotopy groups of spaces of Riemannian metrics with lower curvature bounds for all ${{\operatorname{Spin}}}$ manifolds of dimension 6 or at least 10, which admit such a metric and are a connected sum of some manifold and $S^n \times S^n$ or $S^n \times S^{n+1}$, respectively. We also construct manifolds $M$ whose spaces of Riemannian metrics of positive scalar curvature have homotopy groups that contain elements of infinite order that lie in the image of the orbit map induced by the push-forward action of the diffeomorphism group of $M$.

Isomorphisms between cylinders over Danielewski surfaces

A special Danielewski surface is an affine surface which is the total space of a principal $$({{\mathbb {C}}},+)$$ -bundle over an affine line with a multiple origin. Using a fiber product trick introduced by Danielewski, it is known that cylinders over two such surfaces are always isomorphic provided that both bases have the same number of origins. The goal of this note is to give an explicit method to find isomorphisms between cylinders over special Danielewski surfaces. The method is based on the construction of appropriate locally nilpotent derivations.

Polyfold regularization of constrained moduli spaces

We introduce tame sc-Fredholm sections and slices of sc-Fredholm sections. A slice is a notion of subpolyfold that is compatible with the sc-Fredholm section and has finite locally constant codimension. We prove that the subspace of a tame polyfold that satisfies a transverse sc-smooth constraint in a finite dimensional smooth manifold is a slice of any tame sc-Fredholm section compatible with the constraint. Moreover, we prove that a sc-Fredholm section restricted to a slice is a tame sc-Fredholm section with a drop in Fredholm index given by the codimension of the slice. As a corollary, we obtain fiber products of tame sc-Fredholm sections. We describe applications to Gromov-Witten invariants, constructing the Piunikhin-Salamon-Schwarz maps for general closed symplectic manifolds, and avoiding sphere bubbles in moduli spaces of expected dimension $0$ and $1$.

МОДЕЛЬ ПРОГНОЗИРОВАНИЯ ОСЕВОЙ СИЛЫ РЕЗАНИЯ ПРИ СВЕРЛЕНИИ ОДНОНАПРАВЛЕННЫХ УГЛЕПЛАСТИКОВ С УЧЕТОМ ИЗНОСА РЕЖУЩЕГО ИНСТРУМЕНТА

One of the most important tasks in the production of carbon fiber products is to ensure the specified accuracy and quality of the drilled holes. A model for predicting the thrust force, taking into account the degree of tool wear, is proposed. First, the geometric characteristics of the wear of the spiral drill tool are analyzed. Further, the contact conditions between the drill and the carbon fiber are determined in accordance with the geometric characteristics of the tool wear. Based on the mechanics of the contact interaction of surfaces, the thrust forces of the main cutting edges and the chisel edge are modeled, taking into account the degree of tool wear. The results obtained are integrated into the thrust force prediction model. An example of an experimental study of the drilling carbon fiber is given. The results obtained show a fairly accurate prediction of the cutting force, taking into account the wear of the cutting tool.

Comparative Study of Mechanical Properties and Thermal Stability on Banyan/Ramie Fiber‐Reinforced Hybrid Polymer Composite

The usage of natural fibers has increased recently. They are used to replace synthetic fiber products in aircraft and automobile industries. In this study, natural fibers of bidirectional banyan mat and ramie fabrics are used for reinforcement, and the matrix is an epoxy resin to fabricate composite laminates by traditional hand layup technique at atmospheric temperature mode. Five different sequences of reinforcements are as follows to quantify the effect of thermal stability and mechanical behavior of silane‐treated and untreated hybrid composites. The results revealed that silane‐treated fabric composite laminates were given enhanced mechanical properties of 7% tensile, 11% flexural, and 9% impact strength compared with untreated fabric composite, and at the same time when the increasing of ramie fabric was given the positive influence of 41% improved tensile strength of 40.7 MPa, 49% improved in flexural strength of 38.9 MPa and negative influence in 57% lower impact strength in sample E and positive value in sample A 21.12 J impact energy absorbed in the hybrid composite. Thermogravimetric analysis (TGA) revealed the thermal stability of the hybrid composite. In sample A, the thermal stability is more than in other samples, and 410°C is required to reduce the mass loss of 25%. The working mass condition of the hybrid composite is up to 3.25 g after it moves to degrade.

Foam forming of fiber products: a review

Aqueous foam can be used as a transfer medium to form lightweight materials from natural and man-made fibers together with other types of raw materials. This review discusses mechanisms that underlie the forming process and thus influence physical properties of formed fiber networks such as microporous structure, strength behavior, and transport properties. Homogeneous fiber materials can be formed from versatile raw materials, which makes the technology suitable for a vast range of product applications. An intriguing feature of the method is that the wet foam characteristics provide an additional tool to tailor the performance of the dried material. Understanding foam rheology and how that is affected by added fibers is important in developing the forming process. We introduce both fundamental foam properties and practical forming methods, and show how the material properties are affected by the foam–fiber interaction. The basic features of an industrial production process are also described. The potential material properties are compared against key requirements in typical product applications.

A comprehensive review on dietary fiber and their functional properties in human body

The term 'dietary fiber' (DF) was first presented in the 1950s, alluding to plant cell divided materials; later it was utilized to portray a class of plant-started polysaccharides, which can't be processed and retained in the gastrointestinal plot. Dietary fiber is seen as a physiologically torpid material, and although the best glycemic list building and properties of various fiber sources have for a long while been recognized. Dietary fiber isn't just attractive for its wholesome properties, yet additionally for its useful and mechanical properties. Dietary fiber can be classified in many different ways such as structure and solubility. Based on solubility, they can be divided into soluble or insoluble Dietary Fibres. Soluble Dietary Fibres incorporate oligosaccharides, including fructooligosaccharide (FOS), gelatins, β- glucans (oat and grain grains), galactomannan gums, alginate, and psyllium. Dietary fiber incorporates all non-starch polysaccharides impervious to processing in the small digestive tract and fermentable in the internal organ. Soluble dietary fibres are generally present in plants including agave, garlic, onions, and wheat. Insoluble strands, similar to those found in wheat, grain, vegetables, and organic products. Dietary Fiber analysis is regarded as one of the most tedious assays used in the food industry for nutritional labeling, quality control, and R&D purposes. Recently the food industry has investigated ways of improving the overall nutritional balance of carbohydrate-rich foods and focused on increasing their dietary fiber. This review article reports is evidence regarding fiber enrichment of cereal foods and looks out for future trends in enriched dietary fiber products.

Algorithms to enumerate superspecial Howe curves of genus 4

A Howe curve is a curve of genus $4$ obtained as the fiber product of two genus-$1$ double covers of $\mathbf{P}^1$. In this paper, we present a simple algorithm for testing isomorphism of Howe curves, and we propose two main algorithms for finding and enumerating these curves: One involves solving multivariate systems coming from Cartier--Manin matrices, while the other uses Richelot isogenies of curves of genus $2$. Comparing the two algorithms by implementation and by complexity analyses, we conclude that the latter enumerates curves more efficiently. Using these algorithms, we show that there exist superspecial curves of genus $4$ in characteristic $p$ for every prime $p$ with $7 < p < 20000$.

The association between myofascial trigger points and the incidence of chronic functional constipation

IntroductionChronic functional constipation (CFC) is the most prevalent type of constipation. Considering the proven effect of pelvic floor muscles dysfunction in these patients’ symptom and the fascial connection between pelvic floor and abdominal and lumbopelvic muscles, this study aimed to examine the possible relationship between this muscles and CFC. MethodWe conveniently selected 100 patients with CFC and 100 healthy participants based on the Rome IV criteria. Two groups were asked to complete the international physical activity questionnaire and food frequency questionnaire. Then both groups were assessed for the presence of trigger points in more prevalent pain sites for each muscle by pressure algometer with 50% of their caught pressure pain threshold. ResultsThere were no statistical differences between two groups in the intake of calories, carbohydrates, proteins, sugar, fiber, vegetables, and wheat products. Patients had a higher consumption of fat and dairy products. for the physical activity level, a statistical difference showed that patients were less physically active. The comparison of the presence and the number of trigger points for each muscle in patients and control groups indicated more than 50% impairment, and there was a significant difference between two groups. ConclusionsThis study revealed that the relationship between myofascial trigger points of abdominal and lumbopelvic muscles and constipation. In addition to that, it seems that a sedentary life may influence CFC patients’ condition. Moreover, it seems that the results of the dietary condition in patients could be because of conscious consumption of some certain foods.

Evaluating New York raw fiber-to-retail

Inspired by the slow fashion movement, this is an exploratory case study focused on New York’s raw fiber-to-retail value chain for local clothing and textiles. New York has over 470 diverse sheep, alpaca, goat farms, fiber processing mills for product development, and fiber festivals for retail. A survey with farmers presents their motives for establishing a fiber farm business, diverse fibers available, fiber products, income, and their multiple retail venues. Interviews were conducted with farmers, fiber mill owners, and artisan designers. Primary research objectives included: (1) determining how fiber farms, mills, artisans, fiber festivals, and fiber agro-tourism intersect to sustain the current fiber community; (2) evaluating the major challenges the fiber community faces; (3) determining if stakeholders of the fiber community have benefited from any policies; and (4) understanding future goals New York raw fiber-to-fashion stakeholders have to sustain the local fiber community. Interviews reveal several leadership initiatives developed by fiber farmers to address challenges of finding a market, limited income, and fiber mill closures. This study uses the five key dimensions of slow fashion as a framework to evaluate New York raw fiber-to-retail.

135 Production of a fifty percent functional protein concentrate from the dry grind ethanol process and use of the product in diets for Atlantic salmon

Abstract The corn distilling industry is a major processor of grain, but the high fiber co-product (DDGS), has limited application in feed. Simple mechanical stillage separation downstream of fermentation produces a high protein (52.4 % DM), highly digestible, low crude fiber (4.4% DM) product containing approximately 25% DM spent brewer’s yeast (high density distillers’ protein: HDDP). Currently, approximately 300 ktons of HDDP are produced annually in the USA, and the volume will double in 2020. The effect of graded inclusion levels of HDDP on growth, feed efficiency, nutrient utilization, blood chemistry and gut histology of 525 post-smolt Atlantic salmon (initial body weight 304 ± 10.7g), randomly allocated to three tanks per treatment, was tested in a salt-water recirculating aquaculture system. One control diet with no HDDP was formulated to meet the nutrient requirements of Atlantic salmon. Four test diets were formulated to contain graded levels of HDDP at 5, 10, 15 and 20% respectively. HDDP partially replaced soy protein concentrate and corn protein concentrate in the diets. Salmon were hand-fed to satiety, 3 times daily during the 84-day trial. Throughout the trial the performance of fish on all treatments exceeded commercial growth rates with thermal growth coefficients (TGC) in excess of 0.160 and feed conversion efficiency of ≤ 1.0. Overall HDDP was a nutritious feed ingredient and had no significant impact on performance. Overall TGC was highest (0.200 over the 84-day trial period) in fish fed the diet containing 10% HDDP. Both villi length and villi width in the distal intestine of salmon fed diets containing HDDP tended to be higher than in the controls. Overall, HDDP derived from the dry grind ethanol process was a safe and nutritious novel feed ingredient for Atlantic salmon, and the potential beneficial effect on gut morphology merits investigation.

Enhancing physical properties of mesophase pitch-based graphite fibers by modulating initial stabilization temperature

The development of carbon structures in mesophase pitch fibers was studied with controlling the initial temperature (Ti) of the stabilization process to optimize the mechanical properties of final carbon/graphite fibers. To understand the relationship between Ti and chemical structural change by thermostabilization, the pitch fiber was thermally treated from various Tis up to 350°C with an elevation rate of 2°C/min. Various analyses of the oxygen species in the fiber revealed that changing Ti governed the amount and distribution of oxygen in the stabilized fibers, while determining the effective duration of thermostabilization and preserving hydroxyl groups originally present in the precursor fiber. Among various samples, stabilized fibers with Ti of 150°C contained the largest amount of oxygen in the fiber, resulting in the highest degree of polyaromatic inner structure after the subsequent carbonization and graphitization to show the best tensile strength and modulus. We also demonstrated that the optimal mechanical, electrical, and thermal properties of the resulting graphite fiber were comparable to those of commercially available fiber products (XN-80-60s), indicating that Ti should be carefully considered to enhance the properties of carbon and graphite fibers.

Resurgence numbers of fiber products of projective schemes

We investigate the resurgence and asymptotic resurgence numbers of fiber products of projective schemes. Particularly, we show that while the asymptotic resurgence number of the k-fold fiber product of a projective scheme remains unchanged, its resurgence number could strictly increase.

Current situation and perspectives of ready-to-eat food/meal suppliers.

Working Group 2 of the Healthy Diet Research Committee of International Life Sciences Institute Japan (WG2) assessed the concept and practice of healthy eating in the ready-to-eat food/meal industry in Japan. WG2 interviewed 14 arbitrarily selected member companies that included "health" or "nutrition" in their management policy, and sent a questionnaire to 338 member companies of the Japan Ready-Made Meal Association. Ready-to-eat food/meal suppliers mainly referred to Dietary Reference Intakes for Japanese, the Japanese Food Guide, and/or Healthy Japan 21 for their menu construction. They increased dietary fiber, variety, vegetables, whole-grain cereals, millet rice, and soy bean products; and reduced energy, carbohydrates, and salt in "healthy" food. They tended to avoid making direct appeals to health. Many companies reduced the salt content without drawing attention to the practice. They continually strive to improve flavor as the single most important factor for selling healthy food. The cycling of menus is used to increase diversity in food consumption. These industries require both academia and the government to define priorities for increasing and decreasing particular nutrients as the main targets and to establish the maximum time for balancing each nutrient.

Effect of plasticizers and polymer blends for processing softwood kraft lignin as carbon fiber precursors

Plasticizers depress the glass transition temperature (Tg) of polymers and produce a flowable material at lower temperatures. The use of plasticizers to depress Tg of lignin is important, since at high processing temperatures lignin crosslinks, making it intractable. The goal of this study was to assess plasticizers and polymer blends for the ability to retard a commercial softwood kraft lignin from crosslinking and also serve as thermal and rheological property modifiers during thermal processing in the attempt to produced moldable and spinnable lignin for lignin and carbon fiber products. The Tg of the lignin and the lignin mixed with various amounts of plasticizers and with different thermo-mechanical mixing were determined using differential scanning calorimetry. The Tg and the change in heat capacity at the glass transition (ΔCp) decreased and increased, respectively, about linearly within this plasticizers range with increased plasticizer weight percentage. Gel permeation chromatography results for extruded lignin as well as extruded lignin-plasticizer blends with glycerol, N-allyurea, citric acid with and without sodium hypophosphite, and oleic acid indicate that the presence of these materials reduced the rate of molecular weight increase at temperatures between 100 and 200 °C. Continuous, homogenous films and fibers could be produced by thermal processing with plasticized lignin samples and plasticized lignin-polymer blends, but not with lignin alone. These fibers could be carbonized, yielding up to about 50% of carbon. The present findings have shown the advantages of plasticizers in thermally processing a commercial softwood kraft lignin.

Techno-economic study of a small scale gasifier applied to an indoor hemp farm: From energy savings to biochar effects on productivity

The hemp market is fast growing due to demand for cannabidiol, nutraceutical and hemp fiber products. This work demonstrates the economical advantage of biomass gasification application to indoor hemp production. Gasifiers provide electrical energy, heat and biochar: these are highly valuable products for indoor growers where lights and thermal management are key costs of the business. Energy produced in an autonomous and renewable way increases the sustainability and in the facility. In this paper a small scale gasifier is fueled with certified “A1 plus” wood pellets to test its behavior and its biochar production rate. Biochar is used for hemp growing tests in an indoor hemp production facility. Results show how a 22 kW power plant is sufficient to guarantee almost complete sustainability in a 80 m2 facility. In the best case scenario where energy saving, biochar and thermal energy selling are considered, the gasifier investment has a payback time of about 3.5 years. At the end of the gasifier lifespan, the Net Present Value reaches 249 k€ considering a discount rate of 6%. Consequential results were also obtained from biochar application to pot growing substrates: there was a 7.7% increase in dry flower production and a 33.9% increase in total plant fresh biomass. Cannabinoids profiles resulted not affected by biochar application.

Toric geometry of the Cavender-Farris-Neyman model with a molecular clock

We give a combinatorial description of the toric ideal of invariants of the Cavender-Farris-Neyman model with a molecular clock (CFN-MC) on a rooted binary phylogenetic tree and prove results about the polytope associated to this toric ideal. Key results about the polyhedral structure include that the number of vertices of this polytope is a Fibonacci number, the facets of the polytope can be described using the combinatorial “cluster” structure of the underlying rooted tree, and the volume is equal to an Euler zig-zag number. The toric ideal of invariants of the CFN-MC model has a quadratic Gröbner basis with squarefree initial terms. Finally, we show that the Ehrhart polynomial of these polytopes, and therefore the Hilbert series of the ideals, depends only on the number of leaves of the underlying binary tree, and not on the topology of the tree itself. These results are analogous to classic results for the Cavender-Farris-Neyman model without a molecular clock. However, new techniques are required because the molecular clock assumption destroys the toric fiber product structure that governs group-based models without the molecular clock.