Scholarly Works, Sustainable Biomaterials
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- Cellulose derivatives with a low degree of substitution(United States Patent and Trademark Office, 1996-06-04)The invention is directed to the formation of cellulose derivatives using homogenous phase reaction conditions. Cellulose is dissolved using DMAc/LiCl and a reagent system is added to promote the acylation of an appropriate acid anhydride or free carboxylic acid. One reagent system includes N,N-dicyclohexylcarbodiimide (DCC) and 4-pyrrolidinopyridine (PP). Another reagent system includes p-toluene sulfonyl chloride (TsCl) and pyridine (Py).
- Intra-Ring Compression Strength of Low Density HardwoodsZink-Sharp, Audrey G.; Price, Carlile (Universidad del Bío-Bío, 2006)Engineered wood composites are being crafted with increasingly smaller and smaller components, yet a search of the literature indicates a lack of intra-ring mechanical property data for almost all commercial wood types, particularly the underutilized low density hardwoods. In addition, there is no universally accepted testing regime for determining micromechanical properties of wood samples. As a result, we developed a testing system for determining compression, tension, and bending properties of growth ring regions of wood samples. Our microtesting system consists of a 45.4 kg load stage, motor drive, data acquisition system, motor control, load cell, strain transducer, and software. In this study, intra-ring compression strength parallel to the grain was determined for small samples (a few ml3 in volume) of sweetgum (Liquidambar styraciflua), yellow-poplar (Liriodendron tulipifera), and red maple (Acer rubrum). It was determined that compression strength is weakly correlated with specific gravity but unrelated to growth rate. Specific gravity was also unrelated to growth rate. Sweetgum values were intermediate between yellow-poplar and red maple.
- ¿Cómo integrar la estrategia de una empresa con su sistema de gestión de calidad?Quesada, Henry Jose; Aguilar Rodriguez, Silvia; Espinoza, Carlos (Instituto Tecnologico De Costa Rica, 2006-06-01)Se realizó una investigación con el fin de contar con una guía que permita desarrollar sistemas de gestión de calidad integrados con la estrategia, que no solo evalúen la capacidad de la empresa de ofrecer productos / servicios con el nivel de calidad requerido, sino que también midan la eficacia del sistema de gestión de calidad en apoyar a la empresa a alcanzar su visión. Esto por cuanto lo que se pudo determinar de la situación actual es que se deja a la mera percepción de las gerencias el evaluar la eficacia del sistema de gestión de salidad. La principal conclusión de esta investigación es que los sistemas de gestión de calidad deben dejar de ser operativos y deben pasar a un plano más gerencial, para proveer información que permita tomar decisiones sobre la orientación estratégica de la empresa. Finalmente, se validó la metodología en una empresa y se logró comprobar que la metodología es aplicable, pues permite definir métricas que integren la estrategia de la empresa con su sistema de gestión de calidad y de este modo se facilita la evaluación de la eficacia de dicho sistema.
- Tecnologías avanzadas de manufactura en países en vías de desarrollo una comparación entre Costa Rica y MéxicoQuesada, Henry Jose; Mora Monge, Carlo (Instituto Tecnologico De Costa Rica, 2006-10-01)Hoy, para los países en vías de desarrollo es crítico asegurar sus capacidades de manufactura para poder competir globalmente, en especial cuando hay tratados de libre comercio que se están negociando. Esto es particularmente importante para países como Costa Rica, el cual tiene un tratado de libre comercio con México y está en proceso de aprobación del tratado de libre comercio con los Estados Unidos (CAFTA, por sus siglas en inglés). Mucho se ha dicho sobre si Costa Rica está listo para firmar el tratado. Este artículo provee puntos de vista desde una perspectiva de manufactura y examina las diferencias en inversiones de tecnologías avanzadas de manufactura (AMT, por sus siglas in inglés) y las barreras de implementación entre empresas mexicanas y costarricenses. Después de haber hecho una extensiva investigación sobre AMT en la literatura, dos preguntas de investigación se formularon con respecto a las diferencias entre ambos países. Usando una metodología en forma de cuestionario, la información se recolectó entre 125 empresas, 85 mexicanas y 40 costarricenses. Para probar la hipótesis planteada, se usó el análisis ANOVA (análisis de varianza). Los resultados indican que hay diferencias entre algunas tecnologías y barreras de implementación de AMT entre ambos países.
- Encadenamientos Productivos y su relación con la inversión directa extranjeraQuesada, Henry Jose; Meneses-Guzman, Marcela; Gamboa, Oscar (2008-11-05)Un estudio de competitividad publicado en 2003 por la Promotora de Comercio Exterior de Costa Rica (PROCOMER) revela que Costa Rica muestra bajos niveles en cuanto a sofisticación tecnológica, transferencia de tecnología a partir de la IED, incentivos para la investigación en tecnología y cooperación tecnológica entre empresas. Asimismo, PROCOMER (2003) señala que el desarrollo de clusters de suplidores se encuentra todavía en su etapa inicial. Estos clusters permiten a las empresas involucradas funcionar en forma conjunta y obtener ventajas a partir del encadenamiento de actividades productivas. Estos indicadores de desarrollo incluyen,principalmente, la calidad y cantidad de los proveedores locales. De acuerdo a estos indicadores, en Costa Rica no existe una cantidad adecuada de suplidores locales para las diferentes industrias, y la calidad de los mismos no es la adecuada. En el gráfico 1 se presenta una medida comparativa de índices de desarrollo de clusters de empresas en países que compiten con Costa Rica.
- Evaluation of the Costa Rican Excellence Award for High Quality and PerformanceQuesada, Henry Jose; Meneses-Guzman, Marcela; Monge-Fernández, Guido (Instituto Tecnologico De Costa Rica, 2010-01-06)The use of international and national quality and competitive performance awards has long been recognized as an effective tool to measure outstanding industry performance of private and public organizations worldwide (Hendricks & Singhal, 2000). The importance of developing realistic evaluation models that fit the characteristics of an industry, region, or country, has also been a subject of research for practitioners and academicians for a long time.
- A Case Study to Determine Drivers and Barriers of Appalachian Forest Products in Central AmericaQuesada, Henry Jose; Lyon, Scott; Smith, Robert (Instituto Tecnologico De Costa Rica, 2012-06-04)The purpose of this research was to determine drivers and barriers of Appalachian wood product competitors in Central America. Potential market opportunities for Appalachian forest product companies in Central America were evaluated and strategies were developed to increase exports of Appalachian wood products to Central America. The findings support the claim that United States forest product companies have not put enough effort into marketing forest products to Central America. Forests in El Salvador, Panama, and Costa Rica are limiting harvests and the industry lacks support from the government, reducing the amount of raw material and production. Inconsistencies between Appalachian and Central American wood products industries (e.g., dimensions) act as a barrier to the efficient exchange of wood products. The best market strategies for Appalachian forest products companies to increase sales into Central America are: partner with local wholesalers, offer higher value-added products, and maintain similar pricing with competition. An outside source of wood is needed to meet the needs of growing regional infrastructure.
- Cytotoxicity and Cellular Uptake of Cellulose NanocrystalsDong, Shuping; Hirani, Anjali A.; Colacino, Katelyn R.; Lee, Yong Woo; Roman, Maren (2012-09-21)There is growing evidence that filamentous nanoparticles offer advantages over spherical ones in drug delivery applications. The purpose of this study was to assess the potential of rod-like, plant-derived cellulose nanocrystals (CNCs) for nanomedical uses. Besides a nonspherical morphology, their facile bioconjugation, surface hydrophilicity and small size render CNCs promising drug carriers. The cytotoxicity of CNCs against nine different cell lines (HBMEC, bEnd.3, RAW 264.7, MCF-10A, MDA-MB-231, MDA-MB-468, KB, PC-3 and C6) was determined by MTT and LDH assay. CNCs showed no cytotoxic effects against any of these cell lines in the concentration range and exposure time studied (0–50 µg/mL and 48 h, respectively). Cellular uptake of fluorescein-50 - isothiocyanate-labeled CNCs by these cell lines, quantified with a fluorescence microplate reader, was minimal. The lack of cytotoxicity and the low nonspecific cellular uptake support our hypothesis that CNCs are good candidates for nanomedical applications.
- Quantitative Genetic Background of the Host Influences Gut Microbiomes in ChickensZhao, Lele; Wang, Gang; Siegel, Paul B.; He, Chuan; Wang, Hezhong; Zhao, Wenjing; Zhai, Zhengxiao; Tian, Fengwei; Zhao, Jianxin; Zhang, Hao; Sun, Zikui; Chen, Wei; Zhang, Yan; Meng, He (Nature Publishing Group, 2013-01)Host genotype and gender are among the factors that influence the composition of gut microbiota. We studied the population structure of gut microbiota in two lines of chickens maintained under the same husbandry and dietary regimes. The lines, which originated from a common founder population, had undergone 54 generations of selection for high (HW) or low (LW) 56-day body weight, and now differ by more than 10-fold in body weight at selection age. Of 190 microbiome species, 68 were affected by genotype (line), gender, and genotype by gender interactions. Fifteen of the 68 species belong to Lactobacillus. Species affected by genotype, gender, and the genotype by gender interaction, were 29, 48, and 12, respectively. Species affected by gender were 30 and 17 in the HW and LW lines, respectively. Thus, under a common diet and husbandry host quantitative genotype and gender influenced gut microbiota composite.
- Toxicity of Cellulose Nanocrystals: A ReviewRoman, Maren (2015-02)Cellulose nanocrystals (CNCs) are a biobased nanomaterial attracting increasing interest for a range of potential applications. This article reviews the current literature on the pulmonary, oral, dermal, and cytotoxicity of CNCs. Current studies of the oral and dermal toxicity of CNCs have shown a lack of adverse health effects, whereas studies of the pulmonary and cytotoxicity have yielded discordant results. Additional studies are needed to support the general conclusion that CNCs are nontoxic on ingestion or contact with the skin and to determine whether CNCs have adverse health effects on inhalation or elicit inflammatory or oxidative stress responses at the cellular level. This review underscores the importance of careful sample characterization and exclusion of interfering factors, such as the presence of endotoxins or toxic chemical impurities, for a detailed understanding of the potential adverse health effects of CNCs by various exposure routes.
- Imparting functional variety to cellulose ethers via olefin cross-metathesisDong, Yifan; Edgar, Kevin J. (The Royal Society of Chemistry, 2015-04-09)Olefin cross-metathesis is a valuable new approach for imparting functional variety to cellulose ethers. Starting from commercially available ethyl cellulose, terminally unsaturated alkyl groups were appended as metathesis handles by reaction with allyl chloride, 5-bromo-1-pentene, 7-bromo-1-heptene and 11-bromo-1-undecene, employing sodium hydride catalyst. These olefin-terminal ethyl cellulose derivatives were then subjected to olefin cross-metathesis with a variety of electron-poor olefin substrates, including acrylic acid and acrylate esters under optimized conditions (5–10 mol% Hoveyda-Grubbs’ 2nd generation catalyst, 37 °C, 2 h). The effects of varying the length of the ω-unsaturated alkyl handle, and of the solvent systems used were evaluated. Ethyl cellulose containing a pent-4-enyl substituent performed best in cross metathesis reactions and a hept-6-enyl substituent gave similarly good results. Ethyl cellulose with allyl substituents gave low to moderate metathesis conversion (<50%), possibly due to steric effects and the proximity of the ether oxygen to the terminal olefin. Interestingly, longer tethers (undec-10-enyl) gave high conversions (up to 90%) but relatively slow reactions (ca. 12 h needed for high conversion). While limited in this study by the relatively low DS (OH) of the starting commercial ethyl cellulose materials, this methodology has strong promise for introduction of diverse functionality to cellulose ethers in chemospecific and mild fashion, enabling amorphous solid dispersion and other applications.
- Preparation and evaluation of nanocellulose-gold nanoparticle nanocomposites for SERS applicationsWei, Haoran; Rodriguez, Katia; Renneckar, Scott; Leng, Weinan; Vikesland, Peter J. (The Royal Society of Chemistry, 2015-06-09)Nanocellulose is of research interest due to its extraordinary optical, thermal, and mechanical properties. The incorporation of guest nanoparticles into nanocellulose substrates enables production of novel nanocomposites with a broad range of applications. In this study, gold nanoparticle/bacterial cellulose (AuNP/BC) nanocomposites were prepared and evaluated for their applicability as surface-enhanced Raman scattering (SERS) substrates. The nanocomposites were prepared by citrate mediated in situ reduction of Au3+ in the presence of a BC hydrogel at 303 K. Both the size and morphology of the AuNPs were functions of the HAuCl4 and citrate concentrations. At high HAuCl4 concentrations, Au nanoplates form within the nanocomposites and are responsible for high SERS enhancements. At lower HAuCl4 concentrations, uniform nanospheres form and the SERS enhancement is dependent on the nanosphere size. The time-resolved increase in the SERS signal was probed as a function of drying time with SERS ‘hot-spots’ primarily forming in the final minutes of nanocomposite drying. The application of the AuNP/BC nanocomposites for detection of the SERS active dyes MGITC and R6G as well as the environmental contaminant atrazine is illustrated as is its use under low and high pH conditions. The results indicate the broad applicability of this nanocomposite for analyte detection.
- Variegatic acid from Serpula lacyrmans reduces FeIII and interacts with other fungal metabolites for location-specific generation and scavenging of reactive oxygen speciesZhu, Yuan; Mahaney, James; Jellison, Jody; Cao, Jinzhen; Gressler, Julia; Hoffmeister, Dirk; Goodell, Barry (2016)This study aims to clarify the role of variegatic acid (VA) secreted from Serpula lacyrmans in a chelator-mediated Fenton (CMF) system, including FeIII reduction and the generation of reactive oxygen species (ROS) in the presence of H2O2 and oxalate. As the principle component of the fungal extracellular matrix (ECM), β-glucan isolated from Basidiomycota species was also assessed in scavenging ROS with regard to its potential as a protective barrier for fungal hyphae. Our results demonstrate that VA was effective in reducing FeIII and promoting ROS generation. It is known that oxalate is necessary for solubilization of iron, but both iron reduction and ROS generation were impeded in the presence of oxalate. However, we observed that a higher pH (4.4) favored FeIII transfer from oxalate to VA to drive Fenton-based ROS generation as opposed to a lower pH (2.2), which would be found within the ECM. We propose that a pH-dependent FeIII transfer to VA is employed by S. lacyrmans to permit ROS generation within the higher pH wood cell wall, while limiting ROS production near the fungal hyphae. Further, β-glucan was found to scavenge ROS in acid environments and we postulate that this allows ROS scavenging within the ECM to further limit damage to the fungal hyphae when CMF reactions are active. Data support a role for the ECM in protecting fungal hyphae from ROS generated during decay processes and also support a potential role for a VA-mediated Fenton system in deconstruction of lignocellulose materials by S. lacyrmans.
- Potential for Yield Improvement in Combined Rip-First and Crosscut-First Rough Mill ProcessingThomas, R. Edward; Buehlmann, Urs (2016-02)Traditionally, lumber cutting systems in rough mills have either first ripped lumber into wide strips and then crosscut the resulting strips into component lengths (rip-first), or first crosscut the lumber into component lengths, then ripped the segments to the required widths (crosscut-first). Each method has its advantages and disadvantages. Crosscut-first typically works best for the production of wider components, while rip-first favors the production of narrower and longer components. Thus, whichever type of processing method is selected for a given rough mill usually depends on the characteristics of the cutting bills the mill expects to process. There is a third option, a dual-line mill that contains both ripfirst and crosscut-first processing streams. To date, such mills have been rare for a variety of reasons, complexity and cost being among them. However, dual-line systems allow the mill to respond to varying cutting bill size demands as well as to board characteristics that favor one method (rip-first or crosscut-first) over the other. Using the Rough Mill Simulator (ROMI 4), this paper examines the yield improvement potential of dual-line processing over single-system processing (i.e., rip-first or crosscut-first processing alone) for a variety of cutting bills and lumber grade mixes.
- Changes in the Chemical Composition and Decay Resistance of Thermally-Modified Hevea brasiliensis WoodDurgante Severo, Elias Taylor; Calonego, Fred Willians; Sansigolo, Claudio Angeli; Bond, Brian H. (PLOS, 2016-03-17)In this study the effect of thermal treatment on the equilibrium moisture content, chemical composition and biological resistance to decay fungi of juvenile and mature Hevea brasiliensis wood (rubber wood) was evaluated. Samples were taken from a 53-year-old rubber wood plantation located in Tabapuã, Sao Paulo, Brazil. The samples were thermally-modified at 180°C, 200°C and 220°C. Results indicate that the thermal modification caused: (1) a significant increase in the extractive content and proportional increase in the lignin content at 220°C; (2) a significant decrease in the equilibrium moisture content, holocelluloses, arabinose, galactose and xylose content, but no change in glucose content; and (3) a significant increase in wood decay resistance against both Pycnoporus sanguineus (L.) Murrill and Gloeophyllum trabeum (Pers.) Murrill decay fungi. The greatest decay resistance was achieved from treatment at 220°C which resulted in a change in wood decay resistance class from moderately resistant to resistant. Finally, this study also demonstrated that the influence of thermal treatment in mature wood was lower than in juvenile wood.
- Multifunctional cellulose esters by olefin cross-metathesis and thiol-Michael additionMeng, Xiangtao; Roy Choudhury, Shreya; Edgar, Kevin J. (Royal Society of Chemistry, 2016-04-25)Olefin cross-metathesis (CM) has been shown to be a versatile, mild, modular, and efficient approach to polysaccharide modification. One issue with regard to this approach is the susceptibility of the initial α,β-unsaturated CM derivatives to H-atom abstraction in the γ-position, followed by radical recombination that leads to insoluble, crosslinked products. In our original approach, we resolved this problem through removing the offending unsaturation by hydrogenation. In the current study, we describe a method to exploit these reactive conjugated olefins, by post-CM thiol-Michael addition, thereby appending additional functionality. CM substrates and thiols bearing various functional groups were combined and reacted, employing amine catalysis. Up to 100% conversion was achieved under proper conditions (e.g. catalyst and reaction time), with minimal side reactions observed. The combination of the two modular reactions creates versatile access to cellulose derivatives equipped with a wide diversity of functional groups.
- Amphiphilic hydroxyalkyl cellulose derivatives for amorphous solid dispersion prepared by olefin cross-metathesisDong, Yifan; Mosquera-Giraldo, Laura I.; Troutman, Jacob; Skogstad, Brittny; Taylor, Lynne S.; Edgar, Kevin J. (Royal Society of Chemistry, 2016-07-07)Olefin cross-metathesis (CM) has enabled design and synthesis of diverse, amphiphilic cellulose ether derivatives (e.g. of ethyl and methyl cellulose). In this paper, hydroxyalkyl cellulose was selected as a hydrophilic starting material, with the additional advantage that it has DS (OH) 3.0 that allows targeting of a full range of DS of selected functional groups. Hydroxypropyl cellulose (HPC) was first etherified with 5-bromopent-1-ene to attach olefin “handles” for metathesis, whereby control of molar ratios of sodium hydride and 5-bromopent-1-ene permits full DS control of appended olefin. These olefin-terminated HPC ethers then were subjected to CM with acrylic acid and different acrylates, followed by diimide hydrogenation to reduce the resulting α,β-unsaturation. NMR and FT-IR spectroscopies were useful tools for following reaction progress. One of the product carboxyl-functionalized HPC derivatives, designated HPC-Pen106-AA-H, showed high promise as a crystallization inhibitor of the antiviral drug telaprevir. Its nucleation-induction inhibitory ability was compared to those of commercial controls, HPC and HPMCAS. All three polymers were very effective for inhibiting telaprevir crystallization, increasing induction time up to 8-fold. HPC did not effectively prevent amorphous particle growth, whereas the carboxyl-containing HPC-Pen106-AA-H and HPMCAS were able to prevent formation of agglomerates of amorphous drugs.
- Analysis of electricity consumption: a study in the wood products industryQuesada, Henry Jose; Wiedenbeck, Janice K.; Bond, Brian H. (2016-10)This paper evaluates the effect of industry segment, year, and US region on electricity consumption per employee, per dollar sales, and per square foot of plant area for wood products industries. Data was extracted from the Industrial Assessment Center (IAC) database and imported into MS Excel. The extracted dataset was examined for outliers and abnormalities with outliers outside the quantile range 0.5-99.5 dropped from the analysis. A logarithmic transformation was applied to eliminate the skewness of the original data distributions. Correlation measurements indicated a moderate association between the response variables; therefore, a multivariate analysis of variance test was performed to measure the impact of the three factors: industry type, year, and region, simultaneously on all response variables. The results indicated some effect associated with all three factors on the three measures of electricity consumption. Subsequently, univariate ANOVA tests were conducted to determine the levels of the factors that were different. Most levels of industry type were associated with significantly different energy consumption, an expected result since some of the industries are more energy intensive than others. The industries in Standard Industry Code (SIC) 2493 (reconstituted wood products) are the groups with the highest electricity consumption with means of 38,096.28 kWh/employee, 0.86 kWh/sales, and 154.14 kWh/plant area while industries grouped in SIC 2451 (mobile homes) have the smallest consumption with means of 6811.01 kWh/employee, 0.05 kWh/sales, and 9.45 kWh/plant area. Interestingly, differences in regional consumption were found to be linked to the proportion of industry types by region. Data analysis also indicated differences in electricity consumption per employee for the factor year, but for the other response variables, no differences were found. These main results indicate that industries in the wood products sector have different electricity consumption rates depending on the type of manufacturing processes they use. Therefore, industries in this sector can use these comparisons and metrics to benchmark their electricity consumption as well to understand better how electricity costs might vary depending on the region they are located.
- Competitive Adsorption of Cadmium(II) and Mercury(II) Ions from Aqueous Solutions by Activated Carbon from Xanthoceras sorbifolia Bunge HullZhang, Xiaotao; Hao, Yinan; Wang, Ximing; Chen, Zhangjing; Li, Chun (Hindawi, 2016-12-19)This paper presents low-cost and recyclable activated carbon (XLAC) derived from Xanthoceras sorbifolia Bunge hull for high-efficiency adsorption of Cd(II) and Hg(II) ions in industrial wastewater. XLAC was prepared through H3PO4 activation and was characterized using N2 adsorption-desorption, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDX), and Fourier transform infrared (FTIR) spectroscopy. In single-metal-system adsorption experiments, the maximum adsorption capacities for Cd(II) and Hg(II) obtained under different experimental conditions were 388.7 and 235.6 mg·g−1, respectively. All adsorption equilibrium data fit perfectly with the Langmuir isotherm model. In a binary metal system, competitive studies demonstrated that the presence of Cd(II) significantly decreased the adsorption of Hg(II), but the adsorption of Cd(II) showed a little change in the presence of Hg(II). In addition, XLAC can be regenerated with a 0.01 mol·L−1 HNO3 solution and reused at least four times. The FTIR spectra revealed that a chemical interaction occurs between functional groups containing lone electron pairs in XLAC and metal ions. Overall, these results suggest that XLAC may be suitable as an adsorbent for heavy metal removal from wastewater streams.
- Estimating Component Yield for CLT ProductionBuehlmann, Urs; Thomas, R. Edward (2017)The emergence of cross-laminated timber (CLT) for building construction in North America may provide an additional and possibly more valuable product market for hardwood logs. Using the RaySaw sawing and ROMI rough mill simulators and a digital databank of laser-scanned low-grade yellow-poplar (Liriodendron tulipifera) logs, we examine the yield-recovery potential for components used in the production of CLT. Results include a sawing yield of 65% and a rough-mill yield of 78%, for a total material yield of approximately 50%. This study confirmed the usability of yellow poplar as a material for the production of CLT and allows to estimate the impact on our forest resource of increased use of yellow poplar CLT.