A Logical Model and Data Placement Strategies for MEMS Storage Devices

MEMS storage devices are new non-volatile secondary storages that have outstanding advantages over magnetic disks. MEMS storage devices, however, are much different from magnetic disks in the structure and access characteristics. They have thousands of heads called probe tips and provide the following two major access facilities: (1) flexibility: freely selecting a set of probe tips for accessing data, (2) parallelism: simultaneously reading and writing data with the set of probe tips selected. Due to these characteristics, it is nontrivial to find data placements that fully utilize the capability of MEMS storage devices. In this paper, we propose a simple logical model called the Region-Sector (RS) model that abstracts major characteristics affecting data retrieval performance, such as flexibility and parallelism, from the physical MEMS storage model. We also suggest heuristic data placement strategies based on the RS model and derive new data placements for relational data and two-dimensional spatial data by using those strategies. Experimental results show that the proposed data placements improve the data retrieval performance by up to 4.0 times for relational data and by up to 4.8 times for two-dimensional spatial data of approximately 320 Mbytes compared with those of existing data placements. Further, these improvements are expected to be more marked as the database size grows.Comment: 37 page

Study on multifunctional phosphite-based additives to improve electrochemical properties of LiNi0.5Mn1.5O4 cathodes in lithium ion batteries

Department of Energy Engineering(Battery Science and Technology)Nowadays, lithium ion batteries (LIBs) are one of the fastest growing fields as substitute resources due to relative long term cycle and higher energy density than other batteries. Although LIBs have been commercialized in our life, desire values for extensive applications, which require higher energy/power density such as electric vehicle (EV), hybrid electric vehicle (HEV), plug-in hybrid electric vehicle (PHEV), military and aerospace allications, stationary energy storage still remained challenging. To overcome the limited energy density of LIBs, LiNi0.5Mn1.5O4, which operates in the vicinity of 4.7 V vs. Li/Li+, has been considered as a promising cathode material for LIBs due to high energy densities, low cost, eco-friendly and its high specific capacity. However, there are some defects regarding poor cycle performance in full cell at elevated temperature, severe decomposition of solvent and salt, transition metal dissolution, weakness of storage capacity (self-discharge), and so on. Herein, to resolve the problems of high-voltage LiNi0.5Mn1.5O4 cathode, various organo phosphorus-based additives are investigated as a functional additive forming the solid electrolyte interphase(SEI) layer on the cathode surface. Because this protective later has less resistive character, it can remain to high capacity at high current rate, moreover, indicate superior cycling performance at elevated temperatures in Li/LiNi0.5Mn1.5O4 half cell and graphite/LiNi0.5Mn1.5O4 full cell. To understand the effect of TMSP on the transition metal dissolution, inductively coupled plasma-mass spectrometer (ICP/MS) and energy-dispersive X-ray spectroscopy (EDS) are used as instruments. The results show TMSP-added electrolytes reduce dissolution of Mn and Ni from LiNi0.5Mn1.5O4 cathode. To check structure stability and ability to protect self-discharge at high temperatures, the fully charged cells are stored at 60 oC, and then the samples are transported to ex-situ X-Ray diffraction (XRD), and the data reveals TMSP-derived SEI layer keeps their nature charged structure which means protect self-discharge during storing at 60 oC. Another functional effect is to diminish HF produced by hydrolysis of LiPF6 due to water trace in the cell via 19F and 31P NMR spectra of the electrolyte with and without 0.5wt% TMSP after hydrolysis tests at room temperature. By reducing HF, transition metal dissolution from LiNi0.5Mn1.5O4 cathode by directly attack can be mitigated and protect persistent decomposition of salts. Also, to confirm the critical impact and additional function of organo phosphorus-based additives, we introduce progressive study comparing TMSP with other additives commonly retaining phosphite core. In addition, from an analysis of surface chemistry of SEI layers on the high voltage cathode, we can find similar components of SEI layers formed by various phosphite-added electrolytes via ex-situ X-ray photoelectron spectroscopy (XPS), and propose its common functions which eliminate HF and alleviate decomposition of LiPF6 by hydrolysis via nuclear magnetic resonance (NMR). To understand the effect of various phosphite-types additives regarding self-discharge, open circuit voltage (OCV) of the cells with and without additives is measured at high temperatures during 6 days and capacity retention is conducted after storage. To sum up, there are lots of additives to improve performance of lithium ion battery, TMSP is one of promising additive to make organic and inorganic based SEI layer on the LiNi0.5Mn1.5O4 cathode and show superior electrochemical performance.ope

The Design and Evaluation of a Temporal-aural-visual Representation to Support Middle School Students' Conceptualization of the Range of Imperceptible Sizes.

Supporting students in conceptualizing the range of imperceptibly small sizes (e.g., sizes of atoms or molecules) has been a challenging topic in science education. Commonly used macroscopic visual representations of imperceptible sizes have been unsuccessful, mainly because they perceptually contradict the definition of “imperceptibly small”. Research indicates that learners may benefit from a novel representation that incorporates a non-visual modality for conveying imperceptibly small sizes. To address this issue, an animated temporal-aural-visual representation (TAVR), which accumulates imperceptible objects across the diameter of a pinhead, was designed. In TAVR, the size of an imperceptible object is represented through its total accumulation duration (time necessary to span the pinhead), and the range of imperceptible sizes is conveyed by the range of the accumulation durations of different objects. Prior studies showed that seventh grade middle school students could understand what a TAVR represents and that they constructed more refined mental models of the range of imperceptible sizes after TAVR interactions. However, the roles and the influences of particular TAVR features, which aimed to augment learners’ temporal experiences, in students’ interpretations of the range of imperceptible sizes were unidentified. In this context, this dissertation investigated the TAVR features in three different aspects: the effects of (1) different combinations of aural and visual modalities, (2) different accumulation intervals (ten objects/sec vs. one object/sec), and (3) perception of the passage of time (kinesthetic fast-forwarding vs. natural passage of time), with two hundred thirty-one 7th grade students. Multiple measures including surveys, pre- and post-instructional card-sorting tasks, students’ self-reported reflections, and focus group interviews were examined. The results indicated that the students who interacted with TAVRs with the features that helped them more intensively perceive the durations of the different accumulation progressions (i.e., visual representation, slower accumulation interval, or natural perception of the passage of time) experienced vast range of temporal durations and, hence, generated the most refined mental models of the range of imperceptible sizes. Based on these findings, detailed discussions on the roles of each of the augmenting features in TAVR, possible scenarios for using temporal representations for learning, and future research topics are presented.PHDEducational StudiesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/99991/1/mysong_1.pd

Mice as an Animal Model for Japanese Encephalitis Virus Research: Mouse Susceptibility, Infection Route, and Viral Pathogenesis

Japanese encephalitis virus (JEV), a zoonotic flavivirus, is principally transmitted by hematophagous mosquitoes, continually between susceptible animals and incidentally from those animals to humans. For almost a century since its discovery, JEV was geographically confined to the Asia-Pacific region with recurrent sizable outbreaks involving wildlife, livestock, and people. However, over the past decade, it has been detected for the first time in Europe (Italy) and Africa (Angola) but has yet to cause any recognizable outbreaks in humans. JEV infection leads to a broad spectrum of clinical outcomes, ranging from asymptomatic conditions to self-limiting febrile illnesses to life-threatening neurological complications, particularly Japanese encephalitis (JE). No clinically proven antiviral drugs are available to treat the development and progression of JE. There are, however, several live and killed vaccines that have been commercialized to prevent the infection and transmission of JEV, yet this virus remains the main cause of acute encephalitis syndrome with high morbidity and mortality among children in the endemic regions. Therefore, significant research efforts have been directed toward understanding the neuropathogenesis of JE to facilitate the development of effective treatments for the disease. Thus far, multiple laboratory animal models have been established for the study of JEV infection. In this review, we focus on mice, the most extensively used animal model for JEV research, and summarize the major findings on mouse susceptibility, infection route, and viral pathogenesis reported in the past and present, and discuss some unanswered key questions for future studies

Newly designed coil tube for bowel decompression in patients with small bowel obstructions

AbstractBackgroundThe purpose of this study was to clinically evaluate a coil tube that we recently designed for bowel decompression in patients with a small bowel obstruction.MethodsThe coil tube was composed of a stainless steel coil, a polyolefin tube, and a rubber adaptor. The tube was inserted under fluoroscopic guidance in 14 consecutive patients with small bowel obstructions. Technical success was defined as insertion of the distal end of the tube into at least the proximal jejunum, and clinical success was defined as intestinal decompression and relief of obstructive symptoms.ResultsThe technical success rate was 100%. Clinical success was achieved in 12 patients (86%). The clinical failures were a patient with peritoneal carcinomatosis and an ileocolic fistula, and a patient with bezoars following intestinal hemorrhage. No coil-related complications occurred.ConclusionOur newly designed coil tube was safe and effective in patients with bowel decompression associated with a small bowel obstruction. In addition, our tube has several advantages over other currently used tube types

Effects of C and Al on hydrogen embrittlement mechanism in medium Mn-Ni steels

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Development of a hybrid magnetic resonance/computed tomography-compatible phantom for magnetic resonance guided radiotherapy

The purpose of the present study was to develop a hybrid magnetic resonance/computed tomography (MR/CT)-compatible phantom and tissue-equivalent materials for each MR and CT image. Therefore, the essential requirements necessary for the development of a hybrid MR/CT-compatible phantom were determined and the development process is described. A total of 12 different tissue-equivalent materials for each MR and CT image were developed from chemical components. The uniformity of each sample was calculated. The developed phantom was designed to use 14 plugs that contained various tissue-equivalent materials. Measurement using the developed phantom was performed using a 3.0-T scanner with 32 channels and a Somatom Sensation 64. The maximum percentage difference of the signal intensity (SI) value on MR images after adding K2CO3 was 3.31%. Additionally, the uniformity of each tissue was evaluated by calculating the percent image uniformity (%PIU) of the MR image, which was 82.18 ±1.87% with 83% acceptance, and the average circular-shaped regions of interest (ROIs) on CT images for all samples were within ±5 Hounsfield units (HU). Also, dosimetric evaluation was performed. The percentage differences of each tissue-equivalent sample for average dose ranged from -0.76 to 0.21%. A hybrid MR/CT-compatible phantom for MR and CT was investigated as the first trial in this field of radiation oncology and medical physics