1,720,985 research outputs found
One Belt One Road initiative: A Revolution on Regional and Global Development
Get PDFThe One Belt One Road (OBOR) initiative is a historical landmark which intends to connect more than two-thirds of the world population and opening up the windows for reviving global business, peace and infrastructural development across the countries. The main purpose of this paper is to discuss the OBOR initiative in general and also, to analyze its contribution towards economy and development. The sources of this paper are the published literature, newspaper articles and web information. The paper suggests that though some countries will be benefitted more due to the strategic location advantages, all the member countries will be advantageous if they can use the opportunity with better policy implementation. The authors hope that this paper will be useful for the academicians, policy makers and businessmen who want to study further and implement policies according to the OBOR plan
FINITE ELEMENT BASED METHODOLOGY TO PREDICT FATIGUE COMPRESSION FAILURE IN COMPOSITE BASED ON FIBER KINKING DAMAGE MODEL
Get PDFAdvanced polymer matrix composites are widely used in designing high-performance and lightweight spacecraft, rotorcraft, and automotive structures, due to its superior performance such as specific stiffness, specific strength, and toughness, which are appealing in reducing the weight of these structures. One critical factor that limits the efficient design of structures composed of fiber-reinforced composites (FRP) is the vulnerability of the material under compression loading since compressive strength of FRP material is typically a lot less compared to the tensile strength. Moreover, composite structure may undergo compression loading either by accidentally or by deliberately, large margins of safety are usually imposed in the composite design process, causing in heavyweight and inefficient design. Therefore, the advantage of high elasticity and strength of FRP cannot be fully utilized. Understanding, modeling and finally predicting the compressive response of composite material is a long-standing as it is one of the most complex and widely studied yet unresolved issues. Additionally, the multiplicity of damage modes, their interaction, and complex failure mechanism limits the accurate failure prediction and life assessment of composite structures under compression loading. The uncertainty due to the complexity of failure mechanism, impose risk in a composite design process that cannot be improved by lengthy and expensive testing. Validated analysis techniques capturing the proper mechanism of compressive damage and interaction from initiation to ultimate strength and fatigue failure are essential to provide accurate life assessment of the composite structure. Not to mention, it may assist to identify rooms for improvement to the material system. Fiber micro-buckling or fiber kinking is reported as a primary failure mode of compression failure for FRP composite. Unlike the tensile properties which are generally dictated by reinforcing fibers, under compression, the surrounding matrix and the fiber-matrix interface play a significant role, since they provide the lateral support and restraint to fiber rotation due to compressive load. In this regard, fiber-kinking theory (FKT) is considered as the primary failure mechanism of the composite under compression loading. The objective of this research is to develop a finite element-based methodology to predict fiber-compression fatigue failure which is a well-recognized weakness of carbon-offer reinforced composites. In order to achieve proper fatigue failure prediction in compression loading, preliminary studies have been performed to see if the implemented fiber kinking model can predict the compression failure in quasi-static loading. Therefore, two different carbon/epoxy materials were tested according to the ASTM standard, and the CT scan images were compared with the computational prediction. It was found that including fiber-kinking theory in the computational model help captures the fundamental failure mechanisms such as compression strength, crack location-propagation, and large fiber rotation after failure initiation. The study also shows that accurate prediction of fiber rotation angle which drives the compression failure plays a significant role in capturing the proper material behavior under compression. Based on these outcomes fatigue tests were performed in a short beam shear specimen for two different carbon/epoxy material systems. Through these tests, the key parameter contributing to the change in the material mechanical property during fatigue is identified as the accumulation of permanent shear deformation. Therefore, the fiber-kinking theory is extended and modified to include this change of mechanical shear property during fatigue loading. Additionally, the proposed fatigue model is implemented in the material constitutive model at the fiber misalignment frame using ABAQUS/Explicit FE formulation. Finally, ASTM standard test method D6484 Open Hole Compression is performed, and model predictions are correlated with the test results. The proposed fatigue model based on continuum damage mechanics offers a strong promise in resolving the weakness of the currently available meso-scale fatigue model to predict fatigue compression failure. Furthermore, the proposed model has the ability to predict compressive strength and fatigue behavior in the multidirectional laminate which not only increases the confidence in the material allowable but also has a strong potential to tremendously reduce qualification testing and expand the material composition and layup design space
Angle of Arrival in Bluetooth Location Finding in presence of phase noise
Get PDFThis thesis investigates the strong effects of phase noise in the estimation of Angle of Arrival(AoA), with a focus on Bluetooth Low Energy(BLE) applications. AoA estimation accuracy is often a basic requirement underlying most applications, such as localization and tracking systems, that can bring about severe degradation due to phase noise. In this work, mainly one technique for AoA estimation will be explored, with the understanding that there may be future research into other techniques.
This challenge is thus countered by developing a sophisticated phase noise generator in MATLAB, which emulates realistic experimental settings. The initial research will establish the theoretical grounds for understanding the role of phase noise in AoA estimation. Consecutively, it goes on to describe the design and implementation of a MATLAB simulator built for BLE AoA estimation under practical phase noise conditions. This simulator has been developed as the main tool for making a detailed analysis and evaluation of the chosen AoA estimation technique.
The research estimates that, through extensive simulations, performance degradation due to phase noise gives an idea about the AoA estimation technique. In this paper, another filter was designed with the use of real-life values on phase noise and is being tested with different extents and variances of noise to see how reliable it will turn out to be and at what percentage such performance improvements can be expected. It contributes important insights into the limitations of existing approaches toward AoA estimation and provides hints on ways to improve them.
This thesis is foreseen to create useful contributions toward improving AoA estimation techniques—providing strategies that may reduce the negative impacts from phase noise and increase reliability in BLE localization under noisy conditions
Whole Genome CRISPR-Cas9 Screens Identify Genes Contributing to Viral Entry and Phagocytosis
Get PDFCRISPR/Cas9 is a revolutionary technique for genome editing where Cas9 nucleases can be targeted to specific genomic sites by single-guide RNAs (sgRNAs) containing roughly 20-nucleotide sequences that are complementary to the target region. Double strand breaks created by Cas9 are repaired through non-homologous end-joining (NHEJ) in most cells, resulting in insertions and deletions leading to frame shift mutations in coding regions. Thus, the CRISPR-Cas9 system can be exploited for systematic evaluation of gene function relationships by whole genome screening. We also developed a CRISPR whole‐genome screen and counter‐screen strategy based on a pseudoviral platform that allowed identification of genes specific to SARS‐CoV‐2 spike and vesicular stomatitis virus glycoprotein (VSV‐G) mediated entry. Screening of SARS‐CoV‐2 spike and VSV‐G on the same lentiviral pseudovirus allowed the identification of entry‐specific genes relative to genes associated with retro‐transcription, integration, and reporter expression. Second, a Cre‐Gag fusion protein packaged into the pseudovirus was used to bypass retrotranscription and integration by directly activating a floxed fluorescent protein reporter, thereby increasing specificity for viral entry. Macrophages are important immune cells that engulf pathogens, debris, and apoptotic cells, playing a crucial role in both innate and adaptive immunity. Antibody-dependent cellular phagocytosis (ADCP) is a process where macrophages engulf and destroy pathogens and target cells opsonized by antibodies. We have shown that a Th2 cytokines IL-4 inhibits ADCP of target cells by bone marrow derived macrophages (BMDM). Here, CRISPR-Cas9 whole genome screening on BMDM was used to identify genes that are responsible for IL-4 mediated suppression of ADCP. In this screen, we identified genes contributing to N-linked glycosylation as inhibitors of IL- 4 mediated inhibition of ADCP. Our findings suggest that IL-4 enhances overall glycocalyx abundance, higher negative charge on the cell surface due to the presence of sialic acid at the end of sugar residues, consequently inhibiting target cell phagocytosis through electrostatic repulsion as target cells are also negatively charged. These findings suggest that modulation of glycosylation may be a strategy for enhancing antibody-FcgR interactions and promoting effective immunotherapies for cancer, viral and rheumatological diseases
EFFECT OF NITROGEN AND PHOSPHORUS ON GROWTH AND SEED YIELD OF GIMAKALMI
Get PDFA Thesis
Submitted to the Institute of Seed Technology,
Sher-e-Bangla Agricultural University, Dhaka,
In Partial fulfillment of the requirements
for the degree of
MASTER OF SCIENCE
IN
SEED TECHNOLOGYAn experiment was conducted at the farm of Sher-e-Bangla Agricultural University,
during the period of September 2021 – March, 2022 to study the effect of nitrogen and
phosphorus on growth and seed yield of gimakalmi. Two factors viz., Factor A: 4
nitrogen levels; N
0
(control), N
1
(60 kg N ha
-1
), N
2
(90 kg N ha
-1
) and N
3
)
and Factor B: 4 phosphorus levels viz., P
0
(control), P
1
(20 kg P ha
-1
(120 kg N ha
), P
2
)
and P
3
(40 kg P ha
-1
) were considered for the present study. The experiment was laid out
in a randomized complete block design (RCBD) with three replications. Among nitrogen
treatments, N
2
showed the best performance on seed yield and quality and gave the
highest seed yield (1.79 t ha
-1
), seed germination percentage (85.75%) and seed vigor
index (1269.00) compared to other treatments. Among different phosphorus levels, P
2
gave the best results on seed yield and quality parameters and gave the highest seed yield
ha
-1
(1.85 g), seed germination percentage (85.18%) and seed vigor index (1261.00).
Treatment combination of N
2
P
2
registered the highest number of branches plant
(22.40),
pods plant
-1
(835.90), seed weight plant
-1
(20.88 g), 1000 seed weight (6.24 g), seed yield
plot
-1
(501.10 g), seed yield ha
-1
(2.32 t), stover yield ha
-1
(3.04 t) and harvest index
(43.28%). Regarding quality parameters, the highest seed germination (88.20%), shoot
length (8.14 cm), root length (7.93 cm) and seed vigor index (1417.00) of seedlings after
12 days of germination were also recorded from the seeds produced from the treatment
combination of N
2
P
2
. So, the treatment combination, N
2
P
2
(90 kg N ha
-1
1
)) can be considered as best compared to other treatment combinations
Factors influencing customers buying behavior – A study on RFL-Best Buy Ltd.
No full textCustomer buying behavior is the decision process and acts of people involved in buying and using products. This report explores how different variables impact on customer buying behavior. Demographic variables including perceived economic situation and age; Extrinsic Cue including brand (Advertisement, WOM, and Perceived Price) and Intrinsic Cue that includes perceived quality, perceived value and perceived risk are the important factors that influence customer buying behavior. Present study includes the most important variables including price, brand concentration, brand recognition, that impact the customer buying intension. Using a structured questionnaire this study analyzed data from fifty respondents. Through several descriptive statistics, this study explore some interesting areas including how customers are being influenced, how they react towards a product, how they became familiar with a product, why they ignore or not buying product, how to build a strong customer relationship. Based on the data collected from the customers buying different plastic products from RFL-Best Buy most important variables were identified which include brand equity, perceived value, price, attitude, quality and knowledge. On the basis of the results several important recommendations were forwarded for the practitioners
DISTRIBUTION, CHARACTERISTICS, AND HYDROSTRATIGRAPHY OF PLEISTOCENE AND PLIOCENE FLUVIAL-TERRACE AND ALLUVIAL DEPOSITS IN CENTRAL AND SOUTHERN SHELBY COUNTY, TENNESSEE
Get PDFThis study examined Pleistocene and Pliocene fluvial-terrace and alluvial deposits in Shelby County, Tennessee, with a focus on understanding the relationships between these deposits and subsurface water flow. The Pliocene Upland Complex was identified as a high-level terrace associated with the ancestral Mississippi-Ohio River system that caps the interfluves areas throughout Shelby County. Three Pleistocene terraces were identified - the Intermediate, Hatchie, and Finley, which are found at progressively higher elevations above the modern floodplains of West Tennessee Tributaries (WTT). The Intermediate terrace shows limited distribution, mainly as paleochannels, which do not follow the current east-to-west following WTT. The Hatchie and Finley terrace deposits follow the major WTT and their major tributaries. Gradual changes in water-table elevation contour lines are observed, but no evident intra-aquifer communication exists along the identified near-surface faults. Our sedimentological analysis and subsurface cross-sections revealed a heterogeneous and locally disconnected shallow aquifer
Preliminary Design Of Mesoscale Turbocompressor And Rotordynamics Tests Of Rotor Bearing System
No full textA mesoscale turbocompressor spinning above 500,000 RPM is evolutionary technology for micro turbochargers, turbo blowers, turbo compressors, micro-gas turbines, auxiliary power units, etc for automotive, aerospace, and fuel cell industries. Objectives of this work are:1) to evaluate different air foil bearings designed for the intended applications, and 2) to design & perform CFD analysis of a micro-compressor. CFD analysis of shrouded 3-D micro compressor was conducted using Ansys Bladegen as blade generation tool, ICEM CFD as mesh generation tool, and CFS as main solver for different design and off design cases and also for different number of blades. Comprehensive experimental facilities for testing the turbocompressor system have been also designed and proposed for future work
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