Frictional resistance of geotextiles

The pullout resistance of geotextiles was examined using pullout tests. A suitable wooden box with large (2 ft x 2 ft x 4 ft) dimensions was used to avoid the effect of boundary and to simulate field conditions. Two types of failure patterns were observed. For shallow embedment (\u3c3 ft), geotextile produced a movement of the surrounding mass of sand in the shape of an inverted cone due to interlocking friction between geotextile and sand particles. The cone angle decreases with increase in depth of embedment. For embedment equal to or greater than 3 ft., no sand cone developed and the failure occurred along the interface of geotextile and sand. For 1 ft. surcharge, the increase in the pullout resistance due to combined horizontal and vertical embedment was about 30 %

Damage initiation, progression and failure of polymer matrix composites due to manufacturing induced defects

In polymer matrix composites (PMCs) manufacturing processes can induce de- fects, e.g., voids, fiber misalignment, irregular fiber distribution in the cross-section and broken fibers. The effects of such defects can be beneficial or deleterious de- pending on whether they cause failure suppression or enhancement by localized de- formation processes e.g., crazing, shear yielding and fiber-matrix debonding. In this study, a computational approach is formulated and implemented to develop solu- tions for general boundary-value problems for PMC microstructures that accounts for micromechanics-based constitutive relations including fine scale mechanisms of material failure. The defects considered are voids, and the microstructure is explic- itly represented by a distribution of fibers and voids embedded in a polymer matrix. Fiber is modeled as a linearly elastic material while the polymer matrix is mod- eled as an elastic-viscoplastic material. Two distinct models for the matrix behavior are implemented: (i) DruckerâÂÂPrager type Bodner model that accounts for rate and pressure-sensitivity, and (ii) improved macromolecular constitutive model that also accounts for temperature dependence, small-strain softening and large-strain harden- ing. Damage is simulated by the Gearing-Anand craze model as a reference model and by a new micromechanical craze model, developed to account for craze initiation, growth and breakdown. Critical dilatational energy density criterion is utilized to predict fiber-matrix debonding through cavitation induced matrix cracking. An extensive parametric study is conducted in which the roles of void shape, size and distribution relative to fiber in determining damage initiation and evolution are investigated under imposed temperature and strain rate conditions. Results show there are significant effects of voids on microstructural damage as well as on the overall deformational and failure response of composites

The Effect of E-Service Quality toward Customer Satisfaction: PlayStation Store

A large population of internet users caused the online shopping became more popular nowadays. Not only by shopping physical goods through internet, people now can also purchase and pay for services online, for example by purchasing digital contents through a website. The example for this event is PlayStation Store. Sony PlayStation Store offers digital contents such as base game (digital game), and DLCs (Downloadable Contents) on their site since 2006. PlayStation Store site allows PSN users to provide feedback if they have problems with the PlayStation Network services. Most reported problems that were found in PlayStation Network consists of Sign-in (77%), Game play (11%), and PlayStation Store (10%). The objective of this study is to analyze and to observe the effect of online service quality (e-SQ) toward customer satisfaction using PlayStation Store as an application within this research. Five dimensions of e-SQ are used in this research such as: Efficiency, Reliability, System Availability, Fulfillment, and Privacy. This research used multiple regression analysis with the sample of 385. The most influential variable is Privacy with regression coefficient of 0.372, and System Availability with regression coefficient of 0.219, followed by Reliability with regression coefficient of 0.172, and Efficiency with regression coefficient of 0.129, meanwhile the very least influential is Fulfillment with -0.043. Based on the overall analysis, Sony PlayStation need to improve every aspect related to the Fulfillment variable, which is to provide better service that includes availability, and delivery time to the customer. With these improvements, Sony PlayStation Store would create a better environment regarding to the Fulfillment of products/services toward Customer Satisfaction. Keyword: e-Service Quality, e-Commerce, Customer Satisfaction, PlayStation Store

Reusability Challenges of Scientific Workflows: A Case Study for Galaxy

Scientific workflow has become essential in software engineering because it provides a structured approach to designing, executing, and analyzing scientific experiments. Software developers and researchers have developed hundreds of scientific workflow management systems so scientists in various domains can benefit from them by automating repetitive tasks, enhancing collaboration, and ensuring the reproducibility of their results. However, even for expert users, workflow creation is a complex task due to the dramatic growth of tools and data heterogeneity. Thus, scientists attempt to reuse existing workflows shared in workflow repositories. Unfortunately, several challenges prevent scientists from reusing those workflows. In this study, we thus first attempted to identify those reusability challenges. We also offered an action list and evidence-based guidelines to promote the reusability of scientific workflows. Our intensive manual investigation examined the reusability of existing workflows and exposed several challenges. The challenges preventing reusability include tool upgrading, tool support unavailability, design flaws, incomplete workflows, failure to load a workflow, etc. Such challenges and our action list offered guidelines to future workflow composers to create better workflows with enhanced reusability. In the future, we plan to develop a recommender system using reusable workflows that can assist scientists in creating effective and error-free workflows.Comment: Accepted in APSEC 202

Supporting complex workflows for data-intensive discovery reliably and efficiently

Scientific workflows have emerged as well-established pillars of large-scale computational science and appeared as torchbearers to formalize and structure a massive amount of complex heterogeneous data and accelerate scientific progress. Scientists of diverse domains can analyze their data by constructing scientific workflows as a useful paradigm to manage complex scientific computations. A workflow can analyze terabyte-scale datasets, contain numerous individual tasks, and coordinate between heterogeneous tasks with the help of scientific workflow management systems (SWfMSs). However, even for expert users, workflow creation is a complex task due to the dramatic growth of tools and data heterogeneity. Scientists are now more willing to publicly share scientific datasets and analysis pipelines in the interest of open science. As sharing of research data and resources increases in scientific communities, scientists can reuse existing workflows shared in several workflow repositories. Unfortunately, several challenges can prevent scientists from reusing those workflows, which hurts the purpose of the community-oriented knowledge base. In this thesis, we first identify the repositories that scientists use to share and reuse scientific workflows. Among several repositories, we find Galaxy repositories have numerous workflows, and Galaxy is the mostly used SWfMS. After selecting the Galaxy repositories, we attempt to explore the workflows and encounter several challenges in reusing them. We classify the reusability status (reusable/nonreusable). Based on the effort level, we further categorize the reusable workflows (reusable without modification, easily reusable, moderately difficult to reuse, and difficult to reuse). Upon failure, we record the associated challenges that prevent reusability. We also list the actions upon success. The challenges preventing reusability include tool upgrading, tool support unavailability, design flaws, incomplete workflows, failure to load a workflow, etc. We need to perform several actions to overcome the challenges. The actions include identifying proper input datasets, updating/upgrading tools, finding alternative tools support for obsolete tools, debugging to find the issue creating tools and connections and solving them, modifying tools connections, etc. Such challenges and our action list offer guidelines to future workflow composers to create better workflows with enhanced reusability. A SWfMS stores provenance data at different phases of a workflow life cycle, which can help workflow construction. This provenance data allows reproducibility and knowledge reuse in the scientific community. But, this provenance information is usually many times larger than the workflow and input data, and managing provenance data is growing in complexity with large-scale applications. In our second study, we document the challenges of provenance management and reuse in e-science, focusing primarily on scientific workflow approaches by exploring different SWfMSs and provenance management systems. We also investigate the ways to overcome the challenges. Creating a workflow is difficult but essential for data-intensive complex analysis, and the existing workflows have several challenges to be reused, so in our third study, we build a recommendation system to recommend tool(s) using machine learning approaches to help scientists create optimal, error-free, and efficient workflows by using existing reusable workflows in Galaxy workflow repositories. The findings from our studies and proposed techniques have the potential to simplify the data-intensive analysis, ensuring reliability and efficiency

Penerapkan Model Pembelajaran Two Stay Two Stray Dengan Menggunakan Media Visual Dalam Meningkatkan Hasil Belajar Akuntansi Siswa Kelas XI Smk Swasta Pab 8 Sampali Tahun Ajaran 2016/2017

Penelitian ini bertujuan untuk mengertahui apakah Penerapan Model Pembelajaran kooperatif Two Stay Two Stray(TSTS) dengan menggunakan Media Visual dalam meningkatkan hasil belajar akuntansi siswa Kelas XI SMK PAB 8 Sampali Tahun Pelajaran 2016/2017. Teknik Analisis Data dalam penelitian ini adalah Penelitian Tindakan Kelas (PTK). Teknik dan alat pengumpulan data dalam penelitian ini adalah melalui tes dan lembar observasi. Untuk mengumpulkan data penelitian ini menggunakan tes dalam bentuk uraian. Dan yang menjadi subjek dalam penelitian ini adalah siswa kelas XI SMK Swasta PAB 8Sampali yang berjumlah 42 orang siswapada Tahun Pelajaran 2016/2017. Penelitian ini dilakukan dengan menggunakan 2 siklus, yang setiap siklus nya mempunyai tahapan-tahapan yaitu Perencanaan, Pelaksanaan, Observasi, danRefleksi. Dari hasil penelitian diperoleh bahwa penerapan model pembelajaran Two Stay Two Stray ternyata dapat meningkatkan hasil belajar akuntansi pada kompetensi dasar pencatatan transaksi kedalam neraca lajur. Setelah mengamati hasil belajar dari tes awal (sebelum menerapakan model pembelajaran Two Stay Two Stray) dari 42 siswa hanya 7 dengan persentase 16,67% orang mampu mencapai KKM yang telah ditentukan. Setelah menerapkan model pembelajaran Two Stay Two Stray terjadi peningkatan hasil belajar yaitu pada siklus I terdapat 12 orang siswa yang tuntas dengan persentase 28,58% dan setelah siklus II menjadi 35 orang siswa yang tuntas dengan persentase 83,33% dengan katagori tinggi. Dengan demikian dapat disimpulkan bahwa penerapan model pembelajaran kooperatif tipe Two Stay Two Stray (TSTS) dapat meningkatkan hasil belajar siswa Kelas XI SMK Swasta PAB 8 Sampali tahun Ajaran 2016/2017

Assessment of soil carbon sequestration and climate change mitigation potential under conservation agriculture (CA) practices in the Eastern Gangetic Plains

Conservation agriculture (CA) cropping is based on the principles of minimum soil disturbance, permanent soil cover with crop residue retention and crop rotations with diverse crops. The CA cropping performs well in improving soil health, increasing yield and increasing crop profit in the intensive rice-based, triple–cropping systems on the Eastern Gangetic Plain (EGP), but its effects on the greenhouse gas (GHG) emissions and the dynamics of carbon (C) and nitrogen (N) in the soil has not been studied properly. Two experiments lasting 5 years have examined soil C, N and life cycle GHG emissions in the EGP plains’ intensive rice (Oryza sativa L.)–based cropping soils of Bangladesh. The present study employed a streamlined life cycle assessment (LCA) approach to assess implications of GHGs from CA cropping in comparison with conventional cropping. Minimum disturbance of soil and increased residue retention were assessed at both long-term studies involving rice-based triple cropping systems at Durgapur and Godagari in the EGP since 2010. Component crops of the rice-based systems (lentil (Lens culinaris Medik), mustard (Brassica campestris L.), chickpea (Cicer arietinum L.), jute (Corchorus olitorius L.), early wet season rice & mustard) were established by strip planting (SP) and bed planting (BP), or following 3-4 tillage operations by 2-wheel tractor followed by hand-broadcast seeding and fertilizing (CT). All practices were compared with the conventional low residue retention or increased retention. In case of irrigated and rainfed rice, non-puddled (NP) transplanting were adopted in SP and BP; while soil puddling was used for CT. The life cycle GHG t-1 crop or rice equivalent yield (REY) were assessed under four practices of cropping a) traditional crop establishment practices (CT) with farmers’ practice of residue return (LR), b) CT with return of increased residues (HR); c) strip planting (SP for upland crop)/ transplanting on non-puddled soils (NP for rice) with LR or; d) SP/NP with HR. The cropping systems studied in the long-term trials were mustard-irrigated rice-monsoon rice at Alipur and wheat-jute-monsoon rice at Digram sites. The SP/NP of soils with HR sequestered carbon in soils after five years of cropping at both the locations, relative to current practices of cropping by farmers (CTLR). The increased soil C was associated with reduced CO2eq emissions (13 to 59 % lower than those under CT and BP with LR and HR, respectively, relative to SOC), reduced water soluble carbon (WSC, by 15-23 mg kg-1, relative to CT with LR and HR) contents in soils and increased potentially mineralizable C (PMC) and lower decay rate constant (e.g. 50 % in rice soils). Similarly, at each location (0–10 cm soil depth), SP, including NP, together with HR increased total N by 9 and 32 % relative to BPHR and CTHR and by 62 % relative to the current practice (CTLR), respectively. The increased total N in soil resulted from the increased potentially mineralisable N (PMN) with its low decay rate in soil under all crops with SPHR, relative to other tillage and residue retention practices. The total mineralisation of N in soils under SPHR was statistically equal to (in wheat and jute cropping) or was lower (in mustard and rice cropping) than those under CT with HR. However, soils under SP with residue retention practices had synchronized release of N with crop demand, while CT with LR or HR had increased mineralization during 0–45 days of crop establishment. Conservation agriculture involving SP, and NP of rice, together with HR, has altered the C and N cycling. The alterations were occurred by slowing the early mineralisation of N, reducing the level of mineral N available to plants in the early growing season (low N requirement) but increasing soil total N and plant N uptake by enhancing the synchrony between crop demand and available N supply. In case of C cycling, SP/BP with HR at both the locations modified the C cycle by slowing the in-season turnover of C and by increasing the levels of total organic C in the soil. For all crops in the mustard-irrigated rice-monsoon rice cropping system, SP/NP with LR and HR were the best actual life cycle GHG mitigation option. With the considerable accumulation of SOC (3.8 - 4.2 t CO2eq ha-1) in SP/NP at 0 10 cm soil depth after 5 years in comparison with CT, the life cycle GHG savings with the best mitigation practice (SP/NP with LR) for 1 t of rice-equivalent yield were 46 % relative to CT with LR. Production of 1 t of REY in the rice–based system caused 0.73, 0.74, 0.98 and 1.12 t of CO2eq LCA GHG emission (actual). Production of 1 t of irrigated rice in the EGP after accounting for C sequestered in soils accounted for 0.91, 0.95, 1.25 and 1.41 t CO2eq for NPLR, NPHR, CTLR and CTHR, respectively, whereas the LCA GHGs for the production of 1 t of monsoon rice were 1.10, 1.21, 1.4 and 1.65 t, respectively. For each unit RE mustard production, NPLR, NPHR, CTLR and CTHR were responsible for 0.09, 0.18, 0.31 and 0.29 t CO2eq, respectively. Overall, methane (CH4) released during the on-farm stage of the LCA represented the dominant contributor to LCA GHG in the cropping system. The GHG emitted by machinery usage at on-farm stage (irrigated rice), CO2 emission from soil respiration (monsoon rice), and GHG related to inputs manufacture (REY of mustard) were secondary sources in that order of magnitude. The NPLR and NPHR were the most effective GHG mitigation options when sequestered C was taken into account in footprints of component crops of rice-based rice-upland cropping system. The NPLR and NPHR practices avoided 51 % and 35 % of the actual LCA footprints compared with CTHR and current farmers’ practice, respectively. By not including soil C sequestration in the carbon footprint equation, the life cycle GHG estimates were over-estimated by 9 to 26 %. When soil C sequestration estimated by subtracting C losses from net primary production (NPP) was accounted for in the LCA GHG, the largest decrease in LCA GHG by 20 % was recorded in NPHR but LCA GHG increased by 12 % in CTLR. Overall, the NPLR and NPHR were the most effective GHG mitigation options in production of crops of mustard-irrigated rice-monsoon rice system but NPHR offered yield benefit and its higher CH4 emission was offset by the extra soil organic carbon (SOC) sequestration. The emerging CA approaches being developed for the EGP involving strip planting or NP have the potential to mitigate GWP of intensive rice-based triple cropping systems but further study is needed for a more diverse range of rice-dominant and rice-based triple cropping systems