Synergistic Effects of Processing and Nanofiber Reinforcement on the mechanical and Ferroelectric Performance of Geopolymer Matrix Composites

tThis study involved the evaluation of mechanical and ferroelectric properties of a new classof nanofiller infused inorganic polymer (geopolymer, GP). To evaluate the mechanical per-formance, compressive strength and fracture resistance of neat and nanofillers infused GPwere studied at various treatment temperatures. It was found that, addition of 5 vol% alu-mina nanofiber (ANF), increased compressive strength and modulus by over 30% and 60%,respectively, while it increased fracture toughness (KIC) by over 60% compared to the baselinespecimens. Simultaneously, ferroelectric properties were investigated at various treatmenttemperatures (250◦C, 650◦C and 870◦C). Remarkably, higher ferroelectric hysteresis wasobserved with the GP treated at 870◦C and remnant polarization increased with the addi-tion of alumina nanofiber. Scanning Electron Microscopy confirmed that neat materials arecomposed of particles embedded into the poly-condensed matrix, where particle natureexisted until the treatment temperature reached above 870◦C. X-ray diffraction analysissuggests that, baseline geopolymer started becoming crystalline while the particle naturegradually disappeared with heating at or beyond 870◦C. The bonding between the polymerand alumina nanofiber tends to be stronger with increasing treatment temperature. Theincrease in KICwith the addition of 2 vol% and 5 vol% alumina nanofibers (ANF) is due tohomogeneous dispersion of high interfacial strength nanofillers, which essentially createstrong crack bridging and crack deflection effect. The increase in ferroelectric hysteresisis potentially due to the formation of hierarchical order and domain reorientation of thematerials

Fly Ash Based Geopolymer for High Temperature and High Compressive Strength Applications in Aggressive Environment

Geopolymers are the results of geosynthetic reactions between aluminosilicates and strong bases. This results in chemical bonds between aluminum (Al), Silicon (Si)and oxygen (O) composing polymer rings in tetrahedral coordination. These bonds give them widespread useful applications such as high heat bearing ceramics, and base construction material whilst being far more environmentally conscious. The purpose of the experiment is to examine the effect of Silicon Carbide whisker and inorganic glass particles on thermal and mechanical properties of Geopolymers. This study will help understand the effect of various compositions and concentrations of SiO2 in mechanical strength. In this experiment, the major source of Aluminosilicate material to make the geopolymer paste was fly ash, potassium hydroxide, Potassium silicate, Glass silica and water. A variety of concentrations of Silicon Carbide Whisker and glass particles will be added into geopolymer paste in order to evaluate their performance specifically on compressive strength and thermal conductivity. These are essential properties of cementing materials in energy or heat extraction process. Therefore, the material under investigation has potential for geothermal energy extraction and subterranean structures

Fatal and non-fatal injury outcomes: results from a purposively sampled census of seven rural subdistricts in Bangladesh

Background 90% of the global burden of injuries is borne by low-income and middle-income countries (LMICs). However, details of the injury burden in LMICs are less clear because of the scarcity of data and population-based studies. The Saving of Lives from Drowning project, implemented in rural Bangladesh, did a census on 1·2 million people to fill this gap. This Article describes the epidemiology of fatal and non-fatal injuries from the study. Methods In this study, we used data from the baseline census conducted as part of the Saving of Lives from Drowning (SoLiD) project. The census was implemented in 51 unions from seven purposively sampled rural subdistricts of Bangladesh between June and November, 2013. Sociodemographic, injury mortality, and morbidity information were collected for the whole population in the study area. We analysed the data for descriptive measures of fatal and non-fatal injury outcomes. Age and gender distribution, socioeconomic characteristics, and injury characteristics such as external cause, intent, location, and body part affected were reported for all injury outcomes. Findings The census covered a population of 1 169 593 from 270 387 households and 451 villages. The overall injury mortality rate was 38 deaths per 100 000 population per year, and 104 703 people sustained major non-fatal injuries over a 6-month recall period. Drowning was the leading external cause of injury death for all ages, and falls caused the most number of non-fatal injuries. Fatal injury rates were highest in children aged 1–4 years. Non-fatal injury rates were also highest in children aged 1–4 years and those aged 65 years and older. Males had more fatal and non-fatal injuries than females across all external causes except for burns. Suicide was the leading cause of injury deaths in individuals aged 15–24 years, and more than 50% of the suicides occurred in females. The home environment was the most common location for most injuries. Interpretation The burden of fatal and non-fatal injuries in rural Bangladesh is substantial, accounting for 44 050 deaths and 21 million people suffering major events annually. Targeted approaches addressing drowning in children (especially those aged 1–4 years), falls among the elderly, and suicide among young female adults are urgently needed to reduce injury deaths and morbidity in Bangladesh

Diagnosed hematological malignancies in Bangladesh - a retrospective analysis of over 5000 cases from 10 specialized hospitals

Background The global burden from cancer is rising, especially as low-income countries like Bangladesh observe rapid aging. So far, there are no comprehensive descriptions reporting diagnosed cancer group that include hematological malignancies in Bangladesh. Methods This was a multi-center hospital-based retrospective descriptive study of over 5000 confirmed hematological cancer cases in between January 2008 to December 2012. Morphological typing was carried out using the “French American British” classification system. Results A total of 5013 patients aged between 2 to 90 years had been diagnosed with malignant hematological disorders. A 69.2% were males (n = 3468) and 30.8% females (n = 1545), with a male to female ratio of 2.2:1. The overall median age at diagnosis was 42 years. Acute myeloid leukemia was most frequent (28.3%) with a median age of 35 years, followed by chronic myeloid leukemia with 18.2% (median age 40 years), non-Hodgkin lymphoma (16.9%; median age 48 years), acute lymphoblastic leukemia (14.1%; median age 27 years), multiple myeloma (10.5%; median age 55 years), myelodysplastic syndromes (4.5%; median age 57 years) and Hodgkin’s lymphoma (3.9%; median age 36 years). The least common was chronic lymphocytic leukemia (3.7%; median age 60 years). Below the age of 20 years, acute lymphoblastic leukemia was predominant (37.3%), followed by acute myeloid leukemia (34%). Chronic lymphocytic leukemia and multiple myeloma had mostly occurred among older patients, aged 50-over. Conclusions For the first time, our study presents the pattern and distribution of diagnosed hematological cancers in Bangladesh. It shows differences in population distributions as compared to other settings with possibly a lower presence of non-Hodgkin lymphoma. There might be under-reporting of affected women. Further studies are necessary on the epidemiology, genetics and potential environmental risk factors within this rapidly aging country

Emergence of mcr-1 mediated colistin resistant Escherichia coli from a hospitalized patient in Bangladesh

Introduction: The emergence of plasmid mediated mcr in bacteria has become global public health threat. Herein, we report a mcr-1 positive E. coli in normal human flora from a patient admitted in Dhaka Medical College Hospital (DMCH). Methodology: In total, 700 non-duplicate rectal swabs were collected from DMCH during 13th May to 12th June 2018. E. coli from rectal swabs were isolated on chromogenic UTI media containing vancomycin 10mg/l (Liofilchem, Italy) and confirmed by MALDI-TOF. Minimum inhibitory concentrations (MIC) were determined by agar dilution and interpreted according to EUCAST breakpoints. Genomic analysis of mcr positive E. coli (MCRPEC) was performed by Illumina MiSeq sequencing and pulsed field gel electrophoresis (PFGE) using S1 nuclease DNA digests and blamcr-1 probing. Transferability of blamcr-1 were determined by conjugation assays. Results: We found one MCRPEC from 700 rectal swab screening which was isolated from the rectal swab culture of a 17-year boy who was admitted to the burns ICU, DMCH with 53% flame burn involving much of the trunk and face. Genome sequencing revealed that mcr-1 was present on an IncH12 plasmid of 257,243 bp and flanked by ISApaI1. The colistin resistance can be transferred to the recipient Klebsiella varricola with a frequency of 8.3 × 10-5. Transconjugants were more resistant to colistin than donor (MIC 32 µg/mL). Conclusions: This is the first human associated mcr in Bangladesh. These data indicate the need for a systematic “one health” surveillance in the country

Clinical Spectrum and Management of Diabetic Ketoacidosis: Experience in A Tertiary Care Hospital

Abstract Background: Diabetic ketoacidosis (DKA) is an acute metabolic complication of diabetes mellitus (DM). It may be the presenting feature in type 1 DM, but more commonly it complicates previously diagnosed diabetic patients, both type 1 and type 2. If not recognized early and treated in a judicious way the outcome is often fatal

Finite-difference analysis of stresses of a non-uniform functionally graded material circular disk rotating in the magneto-thermal environment: An equal mass study

The stress field of a functionally graded material rotating disk is studied for different cases of non-uniform thickness variation in the magneto-thermal environment. Three different cases of thickness variation are considered by assuming the variation of non-uniform thickness profiles to be linear, rational, and exponential functions of radius. The mass of the functionally graded material disk is considered equal in all cases of uniform/non-uniform thickness variation. The finite-difference method is used to obtain the numerical results for an Al/Al2O3 functionally graded material disk of fixed-free boundary conditions. The resultant thermo-elastic analysis has shown that the decrease in outer end thickness significantly increases circumferential stress at that end. In the absence of a magnetic field, for the disk with thin outer end thickness minimum stress intensity can be found with linearly varying thickness profile, and high intensity of circumferential stress in case rational and exponential variation of thickness profiles can significantly be reduced with an optimum magnetic field. The transient stress fields and the effect of material properties are also analyzed in detail. All the analyses showed that along with affecting the magnitude, the presence of the magnetic field changes the location and nature of maximum stress in the disk. Finally, results are compared with the finite-element method and available analytical results to verify the analysis

BANGLADESH J CHILD HEALTH 2009; VOL 33 (1) : 6-15 Predictors of Childhood Intractable Epilepsy- A Retrospective Study in A Tertiary Care Hospital

Objective: To study the predictors of intractable childhood epilepsy and to compare the predictors of outcome in early and late onset childhood epilepsy