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

The Martini model, a coarse-grained force field for biomolecular simulations, has found a broad range of applications since its release a decade ago. Based on a building block principle, the model combines speed and versatility while maintaining chemical specificity. Here we review the current state of the model. We describe recent highlights as well as shortcomings, and our ideas on the further development of the model.

/pdf/perspective-on-the-martini-model-48a9823w5f.pdf

Perspective on the Martini model.

Covalent organic frameworks (COFs) represent a new field of rapidly growing chemical research that takes direct inspiration from diverse covalent bonds existing between atoms. The success of linking atoms in two and three dimensions to construct extended framework structures moved the chemistry of COFs beyond the structures to methodologies, highlighting the possibility of prospective applications. Although structure to property relation in COFs has led to fascinating properties, chemical stability, processability and scalability were some of the important challenges that needed to be overcome for their successful implementation. In this Perspective, we take a closer look at the growth of COFs from mere supramolecular structures to potential industrializable materials.

Covalent Organic Frameworks: Chemistry beyond the Structure.

https://cyberleninka.org/article/n/403409.pdf

A review of numerical analysis of friction stir welding

Hybrid composite laminates reinforced with glass/carbon woven fabrics for lightweight load bearing structures

Blast-wave impact-mitigation capability of polyurea when used as helmet suspension-pad material

To combat the problem of traumatic brain injury (TBI), a signature injury of the current military conflicts, there is an urgent need to design head protection systems with superior blast/ballistic impact mitigation capabilities. Toward that end, the blast impact mitigation performance of an advanced combat helmet (ACH) head protection system equipped with polyurea suspension pads and subjected to two different blast peak pressure loadings has been investigated computationally. A fairly detailed (Lagrangian) finite-element model of a helmet/skull/brain assembly is first constructed and placed into an Eulerian air domain through which a single planar blast wave propagates. A combined Eulerian/Lagrangian transient nonlinear dynamics computational fluid/solid interaction analysis is next conducted in order to assess the extent of reduction in intra-cranial shock-wave ingress (responsible for TBI). This was done by comparing temporal evolutions of intra-cranial normal and shear stresses for the cases of an unprotected head and the helmet-protected head and by correlating these quantities with the three most common types of mild traumatic brain injury (mTBI), i.e., axonal damage, contusion, and subdural hemorrhage. The results obtained show that the ACH provides some level of protection against all investigated types of mTBI and that the level of protection increases somewhat with an increase in blast peak pressure. In order to rationalize the aforementioned findings, a shockwave propagation/reflection analysis is carried out for the unprotected head and helmet-protected head cases. The analysis qualitatively corroborated the results pertaining to the blast-mitigation efficacy of an ACH, but also suggested that there are additional shockwave energy dissipation phenomena which play an important role in the mechanical response of the unprotected/protected head to blast impact.

Fluid/Structure Interaction Computational Investigation of Blast-Wave Mitigation Efficacy of the Advanced Combat Helmet

Design and material selection guidelines and strategies for transparent armor systems

A non-equilibrium molecular dynamics method is employed in order to study various phenomena accompanying the generation and propagation of shock waves in polyurea (a micro-phase segregated elastomer). Several recent studies reported in the literature suggested that polyurea has a relatively high potential for mitigation of the effects associated with blast and ballistic impact. This behavior of polyurea is believed to be closely related to its micro-phase segregated microstructure (consisting of the so-called “hard domains” and a soft matrix) and to different phenomena/processes (e.g. inelastic-deformation and energy-dissipation) taking place at, or in the vicinity of, the shock front. The findings obtained in the present analysis are used to help elucidate the molecular-level character of these phenomena/processes. In addition, the analysis yielded the shock Hugoniot (i.e. a set of axial stress vs. density/specific-volume vs. internal energy vs. particle velocity vs. temperature vs. shock speed) material states obtained in polyurea after the passage of a shock wave. The availability of a shock Hugoniot is critical for construction of a high deformation-rate, large-strain, high pressure material models which can be used within a continuum-level computational analysis to capture the response of a polyurea-based macroscopic structure (e.g. blast-protection helmet suspension pads) to blast/ballistic impact loading.

Molecular-level simulations of shock generation and propagation in polyurea

https://apps.dtic.mil/dtic/tr/fulltext/u2/a595399.pdf

B. Pandurangan

Papers

Blast-wave impact-mitigation capability of polyurea when used as helmet suspension-pad material

Fluid/Structure Interaction Computational Investigation of Blast-Wave Mitigation Efficacy of the Advanced Combat Helmet

Design and material selection guidelines and strategies for transparent armor systems

Molecular-level simulations of shock generation and propagation in polyurea

Parameterization of the porous-material model for sand with different levels of water saturation