Specialized Material Research Articles

A Deep Learning Approach for Managing Medical Consumable Materials in Intensive Care Units via Convolutional Neural Networks: Technical Proof-of-Concept Study.

BackgroundHigh numbers of consumable medical materials (eg, sterile needles and swabs) are used during the daily routine of intensive care units (ICUs) worldwide. Although medical consumables largely contribute to total ICU hospital expenditure, many hospitals do not track the individual use of materials. Current tracking solutions meeting the specific requirements of the medical environment, like barcodes or radio frequency identification, require specialized material preparation and high infrastructure investment. This impedes the accurate prediction of consumption, leads to high storage maintenance costs caused by large inventories, and hinders scientific work due to inaccurate documentation. Thus, new cost-effective and contactless methods for object detection are urgently needed.ObjectiveThe goal of this work was to develop and evaluate a contactless visual recognition system for tracking medical consumable materials in ICUs using a deep learning approach on a distributed client-server architecture.MethodsWe developed Consumabot, a novel client-server optical recognition system for medical consumables, based on the convolutional neural network model MobileNet implemented in Tensorflow. The software was designed to run on single-board computer platforms as a detection unit. The system was trained to recognize 20 different materials in the ICU, while 100 sample images of each consumable material were provided. We assessed the top-1 recognition rates in the context of different real-world ICU settings: materials presented to the system without visual obstruction, 50% covered materials, and scenarios of multiple items. We further performed an analysis of variance with repeated measures to quantify the effect of adverse real-world circumstances.ResultsConsumabot reached a >99% reliability of recognition after about 60 steps of training and 150 steps of validation. A desirable low cross entropy of <0.03 was reached for the training set after about 100 iteration steps and after 170 steps for the validation set. The system showed a high top-1 mean recognition accuracy in a real-world scenario of 0.85 (SD 0.11) for objects presented to the system without visual obstruction. Recognition accuracy was lower, but still acceptable, in scenarios where the objects were 50% covered (P<.001; mean recognition accuracy 0.71; SD 0.13) or multiple objects of the target group were present (P=.01; mean recognition accuracy 0.78; SD 0.11), compared to a nonobstructed view. The approach met the criteria of absence of explicit labeling (eg, barcodes, radio frequency labeling) while maintaining a high standard for quality and hygiene with minimal consumption of resources (eg, cost, time, training, and computational power).ConclusionsUsing a convolutional neural network architecture, Consumabot consistently achieved good results in the classification of consumables and thus is a feasible way to recognize and register medical consumables directly to a hospital’s electronic health record. The system shows limitations when the materials are partially covered, therefore identifying characteristics of the consumables are not presented to the system. Further development of the assessment in different medical circumstances is needed.

Recycle of End-of-Life NMC 111 Cathodes By Electrochemical Relithiation

Recycling end-of-life (EoL) lithium ion batteries (LIBs) is of great significance to provide additional transition metal resources and alleviate environmental pollution from batteries wastes, but lags far behind compared with that of lead-acid batteries in the recycling industry. Conventional LIBs recycling methods including pyrometallurgy and hydrometallurgy processes have limitations with regard to energy inefficiency, extensive gas treatment, as well as complex chemical reactions and purification steps for leaching and separating metals. This project is part of ReCell which is a collaborative effort to develop efficient and economical recycle and reuse methods for EoL battery cathodes. The objective of this work is to recover the EoL cathode performance and structure by electrochemical relithiation using a Li metal sacrificial anode since Li ion (Li+) inventory loss plays a significant role for the cathode degradation. The morphology, composition and structure of the initial NMC 111 pristine and chemically delithiated powders used for the ReCell project were characterized through Raman spectroscopy, FIB SEM and TGA. Chemically Delithiated NMC 111 anodes have been prepared and relithiated using a range of temperatures and currents in order to optimize the electrochemical relithiation for application in a roll to roll process. Initial results indicate that elevated temperatures will be necessary to facilitate fast relithiation of the NMC 111 cathodes with the addition of more thermally stable electrolytes. Analysis and characterization of aged NMC 111 anodes in pouch cells is applied to verify the effectiveness of electrochemically relithiated anodes and to compare to the chemically delithiated NMC 111 model material. This study provides more understanding towards developing a battery material recovery process that will potentially recover specialized material morphology and help to minimize energy use and emissions. Figure 1

Stabilization of polyacrylonitrile nanofiber mats obtained by needleless electrospinning using dimethyl sulfoxide as solvent

Polyacrylonitrile can be used as a base material for thermochemical conversion into carbon. Especially nanofiber mats, produced by electrospinning, are of interest to create carbon nanofibers. Optimal stabilization and carbonization parameters, however, strongly depend on the spatial features of the original material. While differences between nano- and microfibers are well known, this paper shows that depending on the electrospinning method and the solvent used, considerable differences between various nanofiber mats have to be taken into account for the optimization of the stabilization conditions. Here, we examine for the first time polyacrylonitrile nanofiber mats, electrospun with wire electrospinning from the low-toxic dimethyl sulfoxide as a solvent, instead of the typically used needle electrospinning from the toxic dimethylformamide. Additionally, we used inexpensive polyacrylonitrile from knitting yarn instead of highly specialized material, tailored for carbonization. Our results show that by carefully controlling the maximum stabilization temperature and especially the heating rate, fully stabilized polyacrylonitrile fibers without undesired interconnections can be created as precursors for carbonization.

A New Simple Analytic Equation for Estimating Asymmetric Growth of Stimulated Reservoir Volume in Anisotropic Shales

Summary The objective of this paper is to present the development and application of a simple equation for calculating the asymmetric growth of the stimulated reservoir volume (SRV) in an anisotropic shale–petroleum reservoir using microseismic data, and the hydraulic diffusivities of the anisotropic shale. Calculation of the SRV is a problem tackled with solutions that involve different degrees of complexity. Because shale reservoirs are anisotropic, microseismic events generally develop 3D nonuniform asymmetric patterns around the injection points. This paper presents a new method with an easy–to–use analytic equation that allows for reproducing the asymmetric growth of microseismic events as a function of time by considering reservoir anisotropy. Asymmetric growth refers to the fact that propagation of the microseismic cloud in a given direction can be larger, equal, or smaller compared with the propagation in other directions. Accurate determination of the SRV asymmetric pattern is critical for use in specialized material–balance and reservoir–simulation models of shale–petroleum reservoirs. This determination allows for more–realistic projections of reservoir performance. The novelty of the method is the development of an easy–to–use approach for estimating SRV in a spatially nonuniform asymmetric anisotropic reservoir using octants in a coordinate system. The SRV is calculated from the volume of a symmetric ellipsoid divided by a constant value Vc. This is despite the fact that the point of injection of the fracturing fluids in the asymmetric reservoir can be at, close to, or far from the center of the ellipsoid. The development of Vc is presented in this paper. Use of the SRV calculation model is illustrated with real microseismic data of the Horn River Shale in Canada for a case where Vc is equal to 1.3722. Also presented are calculations of hydraulic diffusivities in this anisotropic shale.

Thermal decomposition of imidazolium-based ionic liquid binary mixture: Processes and mechanisms

Ionic liquids (ILs) have numerous properties with a wide range of applications as an advanced or specialized material. Mixtures of ILs can further optimize their correlative properties. In this study, the thermal stability of imidazolium-based IL binary mixtures was evaluated by alternating the compound mode and molar fraction (3:7, 5:5, and 7:3) of parent ILs. We found that the thermal stability of the mixtures considerably decreased through a three-step decomposition for specific compound modes. To understand the thermal behaviors of the IL binary mixtures, we argue that the thermal stability of the IL binary mixtures depended on which compounds the ions in the mixture constituted, and that equal molar fractions are deserved to notice for designing IL mixtures. The results of this study can help in the design of relatively stable IL mixtures for proactive loss prevention in the subsequent industrial applications.

Inclusão na educação infantil: desafios e possibilidades através das práticas pedagógicas

This article aims to raise a discourse about the process of inclusion in early childhood education through pedagogical practices. Due to the increasing number of children with special needs entering regular classes in early childhood education, the school needs to be prepared not only in the accessibility part but also in the training of education professionals. And from this perspective, the classroom becomes the place in which the practice constructed in everyday life can promote inclusion. We know of the difficulties encountered in schools for this inclusion to happen, the lack of specialized material, the gaps in training, the lack of teachers, are some of these challenges. Therefore, in this article, based on theorists of the field, we analyze not only the challenges but also the possibilities that we can find through practice, seeking to reflect, and perhaps, finding ways to promote inclusion, that is, to guarantee an education Of quality and respecting the uniqueness of each one.

Typhlotechnics for Persons with Visual Impairment and Quality of Life

This paper deals with the modern trends in typhlotechnics in terms of quality of life for persons with visual impairment. A person with visual impairment is strongly influenced by the development of modern technologies. From the perspective of special education the support of people with visual impairment should take place not only by using the typhlotechnics, artificially made aids, but activity of the individual is equally important. The main method for the outputs of our paper selected was the analysis of foreign and local literature, mostly from the years 2008-2014. Comparison of specialized material allows the evaluation of the current state of development in the area and creation of an informational base for further research projects.

Experimental methods to determine in-plane material properties of polyurethane-coated nylon fabric

Experimental procedures have been developed to obtain the mechanical stiffness and strength properties of an orthotropic polyurethane-coated nylon fabric for use in a finite element analysis of an inflatable, deployable structure. A method that utilizes a specialized material test fixture and photogrammetry to collect the linear and angular displacement data has been employed. Different material holding methods were compared with the objective of producing strength values not influenced by gripping and that allow for use of machine displacement to estimate longitudinal strains during cyclic testing. A series of tension and bias tension tests provided material properties such as Young’s modulus in both warp and fill directions, Poisson’s ratios in plane and through the thickness, and shear modulus. Results obtained from the photogrammetry method show good correlation to machine readings using a pinched gripping method. Additionally, cyclic tests gave the continuous load–unload response and the hysteresis characteristics of the stress–strain in plane and indicated the degree of material degradation. The shear stress–shear strain behavior and shear modulus values are acquired using bias tension tests on 45° skewed specimens.

Reflections on Oral History and Quanto-History: The Larger Context

These thoughtful presentations by Shelly, Jere, Marie, and Alan are reminders of both the importance and the problematic nature of historical writing and research. The limitations of oral especially with respect to its veracity, and the twists of statistical analyses should temper our enthusiasm even as we employ them. You know the movie called Born to Raise Hell [2010]? Well, as college professors, we are born to be skeptical, and it is professionally comforting to see a high level of critical attitude demonstrated by this panel. Oral and quanto-history were popular during the social history movement that peaked in the late 1980s. Social history was inspired by the work of Lucien Lebvre and Marc Bloch of the French Annales School of historical scholarship. (1) The Annales historians emphasized in their work the longue duree--translated extended periods of time, associated thought with culture and geography, saw history as a continuity, used sociological theory and statistics, and gathered large quantities of evidence in hopes of seeing historical problems within the mentality (mentalite in Annales-speak) of an age. A big order. Cultural determinism in the extreme. (2) Though Annales-type social history is no longer pursued so exclusively and with such orthodox purity, it has left its mark on historical writing, (3) and several of us in music education have been much influenced by it. In the context of our subspecialty, it is instructive to look at criticisms of this new history, because we can learn something about the relationship of oral history and quanto-history to larger syntheses. (4) The old view, that of von Ranke, is history from the top down, produced from government documents or the documents of large organizations with emphasis on political and military events--quite the opposite of social which has been most often written from the bottom up, emphasizing the mentality of the everyday population. With the decline in popularity of the social history movement, the writing of history did not return completely to the von Rankean baseline. The nearest equivalent of the von Rankean approach in music education is the work of Birge, whose organization-oriented history we still sacralize. (5) In our mental conceptions, true or false, our subspecialty remains Birge-brained. (6) Criticisms of social history emerged slowly to the larger historical field, much of it from the practitioners of social history itself. For these historians the problem was that analysis of specialized material trumped narrative. Social historians became experts of this or that technique and stuck with it. Data were broken into bits and pieces and huge piles of information collected, resulting in less attention to how it fit the larger historical pattern; that is, less synthesis and consequently less intelligibility. (7) Much social history began to reflect the reductionist fallacy. There was focus on the aspects of evidence, its cuteness, rather than on the interpretion of evidence itself. Like other scholarly trends, these techniques are now moderated, becoming largely integrated into standard historical practice. (8) Obviously, handling a large amount of material and maintaining the story line is a scholarly juggling act. An interesting solution to this is that of Pulitzer Prize-winning David Hackett Fisher, an enthusiastic Annales follower, who has combined narrative with oral and quanto techniques in an arrangement he calls the braided narrative--a story with asides in thick footnotes and extensive appendices--an attempt to understand the mentality of a situation in true Annales style, with depth and completeness, without impeding narrative. (9) The first time this researcher read Fischer's books in the late '80s, he was thrilled about the possibility of documenting and explicating the complexity of music learning. (10) This researcher's Lowell Mason, Samuel A. Worcester, and the Cherokee Singing Book, published in the Chronicles of Oklahoma in the 1990s, had this thickly documented approach and sought to connect music education with the larger narrative of American history and thought. …

비행절차설계과정에서 적용 가능한 위험평가기준 연구

Risk assessment should be processed when physical circumstances of airspace such as establishment of new flight procedures or reconstruction of existing airspace are planned to change and one of the alternatives for the change have to be selected. This is an effort to find the best alternative which is able to maintain at or above the acceptable risk level. ICAO and its contracting states provide specialized guidance material for `Safety Management System` relating to handing airspace matters. These manuals include a conceptual framework for managing safety as well as some of the systemic processes and criteria used to meet the objectives of a State`s safety programme. This criteria must be established in compliance with the State`s laws and regulations for air safety and for the fulfillment of the State`s safety goals. This study is to carry out the risk assessment criteria through literature reviews relevant to the safety management, and to propose the results of criteria to be applicable for establishing flight procedure design process.

Visual Tracking of Plant Virus Infection and Movement Using a Reporter MYB Transcription Factor That Activates Anthocyanin Biosynthesis

Insertion of reporter genes into plant virus genomes is a common experimental strategy to research many aspects of the viral infection dynamics. Their numerous advantages make fluorescent proteins the markers of choice in most studies. However, the use of fluorescent proteins still has some limitations, such as the need of specialized material and facilities to detect the fluorescence. Here, we demonstrate a visual reporter marker system to track virus infection and movement through the plant. The reporter system is based on expression of Antirrhinum majus MYB-related Rosea1 (Ros1) transcription factor (220 amino acids; 25.7 kD) that activates a series of biosynthetic genes leading to accumulation of colored anthocyanins. Using two different tobacco etch potyvirus recombinant clones tagged with Ros1, we show that infected tobacco (Nicotiana tabacum) tissues turn bright red, demonstrating that in this context, the sole expression of Ros1 is sufficient to induce pigment accumulation to a level readily detectable to the naked eye. This marker system also reports viral load qualitatively and quantitatively by means of a very simple extraction process. The Ros1 marker remained stable within the potyvirus genome through successive infectious passages from plant to plant. The main limitation of this marker system is that color output will depend on each particular plant host-virus combination and must be previously tested. However, our experiments demonstrate accurate tracking of turnip mosaic potyvirus infecting Arabidopsis (Arabidopsis thaliana) and either tobacco mosaic virus or potato X virus infecting Nicotiana benthamiana, stressing the general applicability of the method.

Replacing Worn Out Joints: New Materials and Designs Come to Artificial Hips and Knees

Revision rates for joint replacement are tracked in several joint registries in Europe and in Australia. Typically, revision rates at 1% per year are the standard for hip replacements set by NICE (National Institute for Health and Clinical Excellence, UK). At 5 years, for example, the revision rate should not exceed 5%. Joints can fail for reasons other than aseptic loosening such as implant position and the many individual differences in patients, including weight, degree of joint damage, level of activity, and dedication to rehab.Pam Plouhar, Ph.D., world-wide Vice President of Clinical Affairs at DePuy Orthopaedics, says the company's Pinnacle Hip System has a long history of clinical performance and is designed to work well with the younger, active patients who receive hip replacements today. The revision rates are less than 4% at 5 years and comparable or better to this class of hip implants overall. Recently, DePuy had a “ceramic on metal” hip system approved by the FDA.“We're always trying to understand how current innovation impacts the marketplace and how we can leverage that to develop better products to meet the needs of both the surgeons and the patients,” says Plouhar. “Even though the performance of the Pinnacle systems shows less than a 4% revision rate at 5 years, and that is a very good outcome, we're always looking to improve the performance of our products.”Zimmer also has a new bone and growth implant surface called trabecular metal, which goes on a number of hip and knee implants in which no cement is used. The surface that's exposed to bone is made from a specialized material that mimics the microstructure of bone and is conducive to bone growth. Edward Greenfield, Ph.D., Professor and Director of Orthopedic Research at Case Western Reserve University, is working on the osteointegration with Zimmer on their trabecular metal. Greenfield's team is focusing on the hypothesis that bacteria contribute to aseptic loosening. When Greenfield first started mentioning his hypothesis at meetings, his colleagues took a while to warm to the idea. Now, many labs have data in data cell culture and mouse models consistent with that hypothesis.A number of other labs have looked at implants in patients with aseptic loosening and found that many patients have bacterial biofilm on their implants even though there are no clinical signs of infection. That's why it's called aseptic. “That doesn't prove that the biofilm is contributing to loosening; at least it tells you the bacteria are there and the PAMPS [pathogen associated molecular patterns] that bacteria make are presumably there,” says Greenfield.Greenfield's team also really wants to understand how signaling in wear debris works in cell culture and mice and is investigating the role the toll-like receptors (TLRs) play. The researchers are also investigating other bacterial recognition molecules—some downstream of TLR receptors and some that work in parallel. “If, some day, we really show that bacteria are important contributors to aseptic loosening, that suggests that antibacterial strategies might be useful. We're a long way from there,” says Greenfield.Data from the Norwegian Arthroplasty Registry support the bacterial hypothesis. In a study of more than 10,000 primary cemented hip replacements, patients who were given intravenous antibiotics and had antibiotics embedded in the bone cement had fewer revisions.“It may be that you just have to win the race,” says Greenfield.

Automatic Generation of User Material Subroutines for Biomechanical Growth Analysis

The analysis of the biomechanics of growth and remodeling in soft tissues requires the formulation of specialized pseudoelastic constitutive relations. The nonlinear finite element analysis package ABAQUS allows the user to implement such specialized material responses through the coding of a user material subroutine called UMAT. However, hand coding UMAT subroutines is a challenge even for simple pseudoelastic materials and requires substantial time to debug and test the code. To resolve this issue, we develop an automatic UMAT code generation procedure for pseudoelastic materials using the symbolic mathematics package MATHEMATICA and extend the UMAT generator to include continuum growth. The performance of the automatically coded UMAT is tested by simulating the stress-stretch response of a material defined by a Fung-orthotropic strain energy function, subject to uniaxial stretching, equibiaxial stretching, and simple shear in ABAQUS. The MATHEMATICA UMAT generator is then extended to include continuum growth by adding a growth subroutine to the automatically generated UMAT. The MATHEMATICA UMAT generator correctly derives the variables required in the UMAT code, quickly providing a ready-to-use UMAT. In turn, the UMAT accurately simulates the pseudoelastic response. In order to test the growth UMAT, we simulate the growth-based bending of a bilayered bar with differing fiber directions in a nongrowing passive layer. The anisotropic passive layer, being topologically tied to the growing isotropic layer, causes the bending bar to twist laterally. The results of simulations demonstrate the validity of the automatically coded UMAT, used in both standardized tests of hyperelastic materials and for a biomechanical growth analysis.

Tissue‐specific calibration of extracellular matrix material properties by transforming growth factor‐β and Runx2 in bone is required for hearing

Physical cues, such as extracellular matrix stiffness, direct cell differentiation and support tissue-specific function. Perturbation of these cues underlies diverse pathologies, including osteoarthritis, cardiovascular disease and cancer. However, the molecular mechanisms that establish tissue-specific material properties and link them to healthy tissue function are unknown. We show that Runx2, a key lineage-specific transcription factor, regulates the material properties of bone matrix through the same transforming growth factor-β (TGFβ)-responsive pathway that controls osteoblast differentiation. Deregulated TGFβ or Runx2 function compromises the distinctly hard cochlear bone matrix and causes hearing loss, as seen in human cleidocranial dysplasia. In Runx2+/⁻ mice, inhibition of TGFβ signalling rescues both the material properties of the defective matrix, and hearing. This study elucidates the unknown cause of hearing loss in cleidocranial dysplasia, and demonstrates that a molecular pathway controlling cell differentiation also defines material properties of extracellular matrix. Furthermore, our results suggest that the careful regulation of these properties is essential for healthy tissue function.

Finite element modelling of the progressive crushing of braided composite tubes under axial impact

Composite tubular structures are of interest as viable energy absorbing components in vehicular front rail structures to improve crashworthiness. Desirable tools in designing such structures are models capable of simulating damage growth in composite materials. Our model (CODAM for COmposite DAMage), which is a continuum damage mechanics based model for composite materials with physically based inputs, has shown promise in predicting damage evolution and failure in composites. In this study, the model is used to simulate the damage propagation, failure morphology and energy absorption in triaxially braided composite tubes under axial compression. The model parameters are based on results from standard and specialized material testing and a crack band scaling law is used to minimize mesh sensitivity (or lack of objectivity) of the numerical results. Axial crushing of two-ply and four-ply square tubes with and without the presence of an external plug initiator are simulated in LS-DYNA. Refinements over previous attempts by the authors include the addition of a pre-defined debris wedge, a distinguishing feature in tubes displaying a splaying mode of failure, and representation of delamination using a tiebreak contact interface that allows energy absorption through the un-tying process. It is shown that the model adequately predicts the failure characteristics and energy absorption of the crushing events. Using numerical simulations, the process of damage progression is investigated in detail and energy absorptions in different damage mechanisms are presented quantitatively.

A synaptic nidogen: Developmental regulation and role of nidogen-2 at the neuromuscular junction

BackgroundThe skeletal neuromuscular junction is a useful model for elucidating mechanisms that regulate synaptogenesis. Developmentally important intercellular interactions at the neuromuscular junction are mediated by the synaptic portion of a basal lamina that completely ensheaths each muscle fiber. Basal laminas in general are composed of four main types of glycosylated proteins: laminins, collagens IV, heparan sulfate proteoglycans and nidogens (entactins). The portion of the muscle fiber basal lamina that passes between the motor nerve terminal and postsynaptic membrane has been shown to bear distinct isoforms of the first three of these. For laminins and collagens IV, the proteins are deposited by the muscle; a synaptic proteoglycan, z-agrin, is deposited by the nerve. In each case, the synaptic isoform plays key roles in organizing the neuromuscular junction. Here, we analyze the fourth family, composed of nidogen-1 and -2.ResultsIn adult muscle, nidogen-1 is present throughout muscle fiber basal lamina, while nidogen-2 is concentrated at synapses. Nidogen-2 is initially present throughout muscle basal lamina, but is lost from extrasynaptic regions during the first three postnatal weeks. Neuromuscular junctions in mutant mice lacking nidogen-2 appear normal at birth, but become topologically abnormal as they mature. Synaptic laminins, collagens IV and heparan sulfate proteoglycans persist in the absence of nidogen-2, suggesting the phenotype is not secondary to a general defect in the integrity of synaptic basal lamina. Further genetic studies suggest that synaptic localization of each of the four families of synaptic basal lamina components is independent of the other three.ConclusionAll four core components of the basal lamina have synaptically enriched isoforms. Together, they form a highly specialized synaptic cleft material. Individually, they play distinct roles in the formation, maturation and maintenance of the neuromuscular junction.

Forming and scheduling jobs with capacitated containers in semiconductor manufacturing: Single machine problem

We study a scheduling problem motivated by the challenges observed in the newest semiconductor manufacturing wafer fabrication facilities. As wafers are larger and heavier in these wafer fabs, it is becoming more common to use specialized material handling containers that carry multiple orders coming from different customers and to schedule the containers as jobs in the fab. The system performance is a function of the completion times of orders, which ultimately depend on both (1) how the orders are assigned to such containers (“job formation”), and (2) how the containers are scheduled in the fab (“job scheduling”). The overall problem is to find the best way to form and schedule the jobs subject to complicating constraints, including the restrictions on the number of containers that can be used at one time and on the number of wafers the containers can carry. We focus on the single machine job formation and scheduling problem with the total completion time objective. We show that this problem is quite different from conventional parallel and serial batching scenarios and prove that the uncapacitated special case is polynomially solvable and the capacitated case is strongly NP-hard. We use a dynamic programming algorithm to solve the uncapacitated problem, which not only provides tight lower bounds for the capacitated problem, but also becomes a basis for a heuristic approach for the capacitated problem. The computational results show that this approach is very effective, leading to small optimality gaps that get even smaller as the problems become larger.

Finite element modelling of thermal transport in ceramic matrix composites

Ceramic matrix composites, a modern day replacement for specialized material applications especially in aerospace and nuclear industries, involve expensive and elaborate infrastructure for characterization. An alternative is put forth for predicting their characteristics through finite element modelling of a representative unit cell. Their thermal transport behaviour has been modelled using a commercial FE code to conduct steady state and transient analyses on the unit cell. Homogenisation is achieved by bringing multi-phase thermal properties together at the unit cell level to represent an interactive macroscopic thermal behaviour. Manufacturing porosities identified earlier through SEM analyses have also been sequentially included in the modelling scheme with three sub-models, which lead to realistic thermal conductivity values for the final composite unit cell. Effect of subsequent mechanical damage has also been partially captured in the same process thereby extending the proposed scheme to include damage and its effect on thermal transport.

The professionalization of health librarianship in the UK between 1909 and 1978

Many strands exist within health information work and during the last century librarians in this field identified themselves through special groups or associations. This paper focuses on the key role of the Library Association Medical Section in the professional development of medical librarians in the United Kingdom up to 1978 when it merged with the Library Association Hospital Libraries and Handicapped Readers Group to create the Medical, Health and Welfare Group. Uniting to form a stronger organization, under the ultimate designation of the Health Libraries Group, was part of an evolutionary process. The invention and promotion of co-operative schemes, networking and educational opportunities for members, the publication of specialized material and the fostering of international relationships during the first three-quarters of the century are illuminated by personal reminiscences from some of the major participants in the field.

Scheduling material handling vehicles in a container terminal

Increasing global trade has created the need for efficient container ports. The goal of the port is to move containers as quickly as possible and at the least possible cost. Goods that are delayed at the port are inevitably tardy when delivered to the customer, and thus sanctioned by late charges. Two key activities in the port are (i) unloading of containers from truck and then storage in the export area, and (ii) removal of containers from import storage and then loading onto the trucks. Since containers are large and heavy, specialized material handling vehicles are required for transporting them within the terminal. The focus of this paper is on port terminals where straddle carriers are primarily used to move containers. Container terminals typically have well developed computer and communication networks. Through these networks a terminal scheduler will control and schedule the movement of the straddle carrier fleet in real time. The objective of the terminal scheduler is to minimize the empty travel of straddle carriers, while at the same time minimizing any delays in servicing customers. This paper presents a straddle scheduling procedure that can be used by a terminal scheduler to control the movement of straddle carriers. At its core, the procedure is driven by an assignment algorithm that dynamically matches straddle carriers and trucks, as each becomes available. The procedures were developed and tested in collaboration with the largest container terminal operator in the Port of New York and New Jersey. Using a simulation model of the real system, the superiority of the proposed procedure over two alternative scheduling strategies is illustrated.