Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Fast parallel algorithms for short-range molecular dynamics

THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

This critical review provides a processing-structure-property perspective on recent advances in cellulose nanoparticles and composites produced from them. It summarizes cellulose nanoparticles in terms of particle morphology, crystal structure, and properties. Also described are the self-assembly and rheological properties of cellulose nanoparticle suspensions. The methodology of composite processing and resulting properties are fully covered, with an emphasis on neat and high fraction cellulose composites. Additionally, advances in predictive modeling from molecular dynamic simulations of crystalline cellulose to the continuum modeling of composites made with such particles are reviewed (392 references).

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Cellulose nanomaterials review: structure, properties and nanocomposites

Fundamental features of microbial cellulose utilization are examined at successively higher levels of aggregation encompassing the structure and composition of cellulosic biomass, taxonomic diversity, cellulase enzyme systems, molecular biology of cellulase enzymes, physiology of cellulolytic microorganisms, ecological aspects of cellulase-degrading communities, and rate-limiting factors in nature. The methodological basis for studying microbial cellulose utilization is considered relative to quantification of cells and enzymes in the presence of solid substrates as well as apparatus and analysis for cellulose-grown continuous cultures. Quantitative description of cellulose hydrolysis is addressed with respect to adsorption of cellulase enzymes, rates of enzymatic hydrolysis, bioenergetics of microbial cellulose utilization, kinetics of microbial cellulose utilization, and contrasting features compared to soluble substrate kinetics. A biological perspective on processing cellulosic biomass is presented, including features of pretreated substrates and alternative process configurations. Organism development is considered for "consolidated bioprocessing" (CBP), in which the production of cellulolytic enzymes, hydrolysis of biomass, and fermentation of resulting sugars to desired products occur in one step. Two organism development strategies for CBP are examined: (i) improve product yield and tolerance in microorganisms able to utilize cellulose, or (ii) express a heterologous system for cellulose hydrolysis and utilization in microorganisms that exhibit high product yield and tolerance. A concluding discussion identifies unresolved issues pertaining to microbial cellulose utilization, suggests approaches by which such issues might be resolved, and contrasts a microbially oriented cellulose hydrolysis paradigm to the more conventional enzymatically oriented paradigm in both fundamental and applied contexts.

/pdf/microbial-cellulose-utilization-fundamentals-and-4yec12qx1c.pdf

Microbial cellulose utilization: fundamentals and biotechnology.

Physiological and ecological constraints play key roles in the evolution of plant growth patterns, especially in relation to defenses against herbivores. Phenotypic and life history theories are unified within the growth-differentiation balance (GDB) framework, forming an integrated system of theories explaining and predicting patterns of plant defense and competitive interactions in ecological and evolutionary time. Plant activity at the cellular level can be classified as growth (cell division and enlargement) of differentiation (chemical and morphological changes leading to cell maturation and specialization). The GDB hypothesis of plant defense is premised upon a physiological trade-off between growth and differentiation processes. The trade-off between growth and defense exists because secondary metabolism and structural reinforcement are physiologically constrained in dividing and enlarging cells, and because they divert resources from the production of new leaf area. Hence the dilemma of plants: Th...

https://www.jstor.org/stable/pdfplus/2830650.pdf

The dilemma of plants: To grow or defend.

Part 1 Review Topics Historical Development of Adhesives and Adhesive Bonding Fundamental Aspects Theories and Mechanisms of Adhesion Application of Plasma Technology for Improved Adhesion of Materials Silane and Other Adhesion Promoters in Adhesive Technology Testing of Adhesives Physical Testing of Pressure-Sensitive Adhesive Systems Durability of Adhesive Joints Analysis of Adhesives Fracture of Adhesive-Bonded Wood Joints Spectroscopic Techniques in Adhesive Bonding Ultraviolet Stabilization of Adhesives Part 2: Adhesive Classes Protein Adhesives for Wood Animal Glues and Adhesives Carbohydrate Polymers as Adhesives Natural Rubber-Based Adhesives Polysulfide Sealants and Adhesives Phenolic Resin Adhesives Natural Phenolic Adhesives - Tannin, Lignin Resorcinol Adhesives Urea-Formaldehyde Adhesives Melamine-Formaldehyde Adhesives Polyurethane Adhesives Part 3 Applications of Adhesives: Adhesives in the Electronics Industry Adhesives in the Wood Industry Bioadhesives in Drug Delivery Bonding Materials and Techniques in Dentistry Adhesives in the Automotive Industry

Handbook of adhesive technology

Relatively mild thermal treatments of wood according to a two step process which leads to improved dimensional stability and improved timber performance were investigated by solid phase CP-MAS 13C-NMR to understand at molecular level the reasons for the improvements reported. All the occurrences described appear to be the consequence of reactions which are known in wood chemistry. These are the formation of acetic acid liberated from the hemicelluloses, which further catalyses carbohydrates cleavage, causing a reduction of degree of polymerisation of the carbohydrates. Acid catalysed degradation results in the formation of formaldehyde, furfural and other aldehydes as well as some lignin cleavage at Cα and O4 and believed to cause some aldehyde production from lignin units Cγ, all occurring in the first reaction step. Lignin autocondensation through the cleaved, positively charged benzylic Cα to form some methylene bridges presumably starts already to occur in this first phase. The increase in the number of free reactive sites on the aromatic ring of some lignin units already occurs in this phase but continues into the next. In the second treatment step completion of the autocondensation of lignin is believed to occur through the formation of methylene bridges connecting aromatic rings. The aromatic nuclei sites are released by demethoxylation and through the cleaved, positively charged benzylic Cα. Reactions of some of the aldehyde groups formed in the first step phase occur with lignin aromatic nuclei sites to connect aromatic rings through methylene bridges. The extent of these reactions is mild, but nonetheless they lead to an increase in cross-linking with consequent improvement in dimensional stability and decreased hygroscopicity of wood.

Characterisation of thermally modified wood: molecular reasons for wood performance improvement

and 46% for P. placenta. About 56% and 54% weight loss were obtained for southern pine control exposed to G. trabeum and P. placenta, respectively. The weight loss of the water and acetone extracted heat-treated sample exposed to P. placenta was 49.7% and 53.9%, respectively. Only about 11% and 14.8% weight loss was obtained for water and acetone extracted samples exposed to G. trabeum. The moisture content of the tested samples was about 70 ± 10% for the un-heated controls and 50 ± 10% for heat-treated samples. This treatment may modify the durability from non-resistant to moderate/resistant species depending on the fungus species as defined in the ASTM 2017 standard. The data from the bending test indicate that such treatment may create a 10 to 50% reduction in MOR and deflection, which will limit the use of such wood for structural purposes.

Durability of heat-treated wood

Brief Nonmathematical Review of Adhesion Theories as Applicable to Wood Urea-Formaldehyde Adhesives Melamine-Formaldehyde Adhesives Phenolic Resin Wood Adhesives Tannin-Based Wood Adhesives Lignin-Based Wood Adhesives Resorcinol Adhesives Diisocyanate Wood Adhesives.

Advanced Wood Adhesives Technology

Recent developments and trends in the field of eco-efficient bio-based adhesives are reviewed. Eco-efficient means efficient with regard to both ecological and economical aspects. The recent developments in tannin adhesives without the use of any aldehyde-yielding compounds under the conditions of use, or even without the use of any hardeners, are described. Lignin adhesives are discussed next. Developments in protein adhesives, particularly the recent development in soy protein adhesives, are then addressed. Several new trends in carbohydrate adhesives, namely as modifiers of existing adhesives, by forming degradation compounds such as furanic compounds which can then be used as adhesives building blocks, and directly as wood adhesives, even in the form of liquified wood, are addressed. Unsaturated oil adhesives based on epoxidized unsaturated vegetable oils are also described, as well as an example of cashew nut shell oil modified by a new and inexpensive method of ozonolysis to yield an adhesive by sel...

Antonio Pizzi

Papers

Handbook of adhesive technology

Characterisation of thermally modified wood: molecular reasons for wood performance improvement

Durability of heat-treated wood

Advanced Wood Adhesives Technology

Recent developments in eco-efficient bio-based adhesives for wood bonding: opportunities and issues