Optimal Structural Results for Assemble-to-Order Generalized M-Systmes

Cataloged from PDF version of article.We consider an assemble-to-order generalized M-system with multiple components and multiple products, batch ordering of components, random lead times, and lost sales. We model the system as an in nite-horizon Markov decision process and seek an optimal control policy, which speci es when a batch of components should be produced and whether an arriving demand for each product should be satis ed. To facilitate our analysis, we introduce new functional characterizations for convexity and submodularity with respect to certain non-unitary directions. These help us characterize optimal inventory replenishment and allocation policies under a mild condition on component batch sizes via a new type of policy: lattice-dependent base-stock and lattice-dependent rationing

New chromosome numbers in the genus Trigonella L. (Fabaceae)from Turkey

Somatic chromosome numbers of 45 Trigonella L. (Fabaceae), collected from different localities in Turkey was examined. Chromosome numbers were determined as 2n = 14, 16, 30 and 46. B chromosome was also observed in somatic cells of some taxa (Trigonella arcuata C.A. Meyer and Trigonella procumbens (Besser) Reichb.). In addition, one or two satellites were observed in some taxa (Trigonella lunata Boiss., Trigonella velutina Boiss., Trigonella strangulata Boiss., Trigonella crassipes Boiss. and Trigonella cariensis Boiss.).Keywords: Chromosome number, Leguminosae, Trigonell

Transmitter and Receiver Architectures for Molecular Communications: A Survey on Physical Design with Modulation, Coding, and Detection Techniques

Inspired by nature, molecular communications (MC), i.e., the use of molecules to encode, transmit, and receive information, stands as the most promising communication paradigm to realize the nanonetworks. Even though there has been extensive theoretical research toward nanoscale MC, there are no examples of implemented nanoscale MC networks. The main reason for this lies in the peculiarities of nanoscale physics, challenges in nanoscale fabrication, and highly stochastic nature of the biochemical domain of envisioned nanonetwork applications. This mandates developing novel device architectures and communication methods compatible with MC constraints. To that end, various transmitter and receiver designs for MC have been proposed in the literature together with numerable modulation, coding, and detection techniques. However, these works fall into domains of a very wide spectrum of disciplines, including, but not limited to, information and communication theory, quantum physics, materials science, nanofabrication, physiology, and synthetic biology. Therefore, we believe it is imperative for the progress of the field that an organized exposition of cumulative knowledge on the subject matter can be compiled. Thus, to fill this gap, in this comprehensive survey, we review the existing literature on transmitter and receiver architectures toward realizing MC among nanomaterial-based nanomachines and/or biological entities and provide a complete overview of modulation, coding, and detection techniques employed for MC. Moreover, we identify the most significant shortcomings and challenges in all these research areas and propose potential solutions to overcome some of them.This work was supported in part by the European Research Council (ERC) Projects MINERVA under Grant ERC-2013-CoG #616922 and MINERGRACE under Grant ERC-2017-PoC #780645

High density bimodal parts by three dimensional printing

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1998.Includes bibliographical references (p. 102-103).Three Dimensional Printing (3DP) is a rapid prototyping process that allows for the fabrication of injection molding tooling from computer generated models. Due to market demands for harder, more robust tooling, improving the material properties and the geometric control of 3DP parts has been a necessary goal of the project. One path to accomplishing this task is to increase the green density of the 3DP compact prior to sintering. To accomplish this goal, the printing of fine, sub-micron Titanium Carbide slurries into a large powder bed to create a dense bimodal compact was investigated. Experiments performed demonstrated that a uniform, defect free microstructure could be obtained by appropriately selecting 3DP process parameters. By spreading 4 mil layers, and double printing, sample coupons with estimated green densities of up to 83% were obtained. In addition, the effect of varying either the bimodal concentrations or the relative particle sizes, on fine porosity in 3DP parts after infiltration was studied. Three bimodal ceramic-metal material systems, each based on Titanium Carbide and subsequently infiltrated with a copper-nickel-manganese alloy, were also developed. The first system, a bimodal system of large TiC and fine TiC powders exhibits good dimensional control (net shrinkage of 0.2%) and age-hardening properties (up to 43 HRC). The second system, a bimodal system of large Stainless Steel and fine TiC powders, is characterized by modest dimensional control (less than 2%), but does not exhibit any age-hardening behavior. The third system developed, a bimodal system of large Molybdenum powders and fine TiC powders, can be hardened up to 25 HRC with a 12 hour 400°C treatment.by Akan E. Oton.S.M

Graphene and Related Materials for the Internet of Bio-Nano Things

Internet of Bio-Nano Things (IoBNT) is a transformative communication framework, characterized by heterogeneous networks comprising both biological entities and artificial micro/nano-scale devices, so-called Bio-Nano Things (BNTs), interfaced with conventional communication networks for enabling innovative biomedical and environmental applications. Realizing the potential of IoBNT requires the development of new and unconventional communication technologies, such as molecular communications, as well as the corresponding transceivers, bio-cyber interfacing technologies connecting the biochemical domain of IoBNT to the electromagnetic domain of conventional networks, and miniaturized energy harvesting and storage components for the continuous power supply to BNTs. Graphene and related materials (GRMs) exhibit exceptional electrical, optical, biochemical, and mechanical properties, rendering them ideal candidates for addressing the challenges posed by IoBNT. This perspective article highlights recent advancements in GRM-based device technologies that are promising for implementing the core components of IoBNT. By identifying the unique opportunities afforded by GRMs and aligning them with the practical challenges associated with IoBNT, particularly in the materials domain, our aim is to accelerate the transition of envisaged IoBNT applications from theoretical concepts to practical implementations, while also uncovering new application areas for GRMs

Chronic Wounds in Children: Prevalence, Aetiological Types and Predilection Sites in a Rural Setting in an Emerging Economy

The aim of this study was to determine the prevalence, aetiological types and predilection sites of chronic wounds in children. This study was a cross sectional study conducted on children aged 0-15 years. Through cluster sampling technique, children with wounds were recruited and evaluated. Demographic and clinical data were collected and analyzed. Descriptive statistics were used to summarize variables and Chi-squared test was used to achieve comparison between age groups and sexes. Statistical significance was defined as p<0.05. The results show that one thousand and ten children were screened for wounds out of which 107 children with 115 wounds were found. 16.5% of these wounds were chronic with a prevalence rate of 2.0%. Chronic wound prevalences in the school aged (47.4%) and adolescent (52.6%) children were 0.9% and 1.0% respectively (x2 = 0.821; p = 0.359 Yates’ corrected, Fisher’s exact test 2-sided) and statistically insignificant. 57.9% were caused by trauma and majority (89.5%) occurred in the lower limbs (x2=0.000; p=1.000 Yates’ corrected, Fisher’s exact test 2-sided) without any statistical significance. Prevalence of chronic wounds in the children population was very low. The commonest aetiological type was inadequately treated traumatic wounds which progressively healed on institution of appropriate wound treatment