Piston ring assembly for a new natural gas vehicle symmetrical multistage wobble-plate compressor

Natural gas is an alternative fuel of choice in the market today due to the increase in the price of petroleum, as well as out of environmental concerns. Pressure requirement for a natural gas vehicle (NGV) storage tank is 3000 psig (206 bars). Thus, at NGV refueling facilities, the natural gas need to be stored at a higher pressure in order to refuel the NGV at the pressure required. Compressors are needed in the compression process at the refueling facilities. A new compressor design for natural gas refueling appliance has been developed which is the symmetrical multistage wobble-plate compressor. This compressor design is the newest variation of the axial reciprocating piston compressor. The success of the compressor design in compressing gas depends on the piston ring assembly design. Through this paper, the process of designing the piston ring assembly and considerations taken for this new compressor design were explained. The results presented are those from preliminary tests using air on the working fluid. Real tests on natural gas are to be organised utilising all the experience and lesson learnt from that on air

Эффективность фотодинамического воздействия в сочетании с озоном и хлорофиллом из листьев Dracaena angustifolia на биопленки Staphylicoccus aureus

Photodynamic inactivation is an effective treatment that uses light irradiation, photosensitizer and oxygen. The aim of this study was to determine photodynamic effectiveness of laser diode combined with ozone to reduce Staphylococcus aureus biofilm using exogenous chlorophyll (Chlo). The chlorophyll was extracted from leave of Dracaena angustifolia. To determine the antibacterial effect of S. aureus biofilm treatments, samples were separated into Chlo, Laser, Chlo+Laser, Ozone, Ozone+Laser, Chlo+Ozone+Laser categories. The data were analyzed using ANOVA test. The result of this study showed that Chlo+Ozone+Laser combine treatment at 20 s exposure of ozone with 4 min of irradiation time lead to 80.26 % reduction of biofilm activity, which was the highest efficacy of all the treatment groups. The combination of laser, chlorophyll and lower ozone concentration increases the effectiveness of photodynamic inactivation.Фотодинамическая терапия – эффективный метод инактивации бактериальных биопленок, основанный на сочетании воздействий светового излучения, фотосенсибилизатора и кислорода. Цель данного исследования – определение эффективности лазерного облу- чения в сочетании с озоном при добавлении экзогенного хлорофилла для инактивации биопленки Staphylococcus aureus (S. aureus). Хлорофилл был извлечен из листьев растения Dracaena angustifolia. В ходе исследования на образцах биопленки S. aureus оценива- лась антибактериальная активность каждого фактора в отдельности (лазерное излучение, озон, хлорофилл) и нескольких их сочета- ний (хлорофилл + лазерное облучение; озон + лазерное облучение; хлорофилл + озон + лазерное облучение). Полученные данные были проанализированы с использованием теста ANOVA. Анализ результатов исследования показал, что комбинированная обра- ботка озоном в течение 20 с в присутствии хлорофилла с последующим облучением в течение 4 мин снизила активность биопленок на 80,26%, показав самую высокую эффективность среди всех тестируемых групп. Для повышения эффективности фотодинамической терапии бактериальных биопленок рекомендуется использовать комбинацию лазерного излучения с хлорофиллом и озоном

Links between microstructural properties of cancellous bone and its mechanical response to different strain rates.

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Analysis of trace metal contamination in Pahang River and Kelantan River, Malaysia

The primary objective of this study is to determine trace metal contamination in environmental samples obtained from Pahang River and Kelantan River, Malaysia which may help to identify the risk of sustainable dredging in these areas. This research also proceeds to compare the trace metal concentration with the National Water Quality Standards of Malaysia, Interim Canadian Sediment Quality Guidelines and Malaysian Food Act 1983 to determine its limits and risks. Samples of water, sediment, snails and fishes were collected and analyzed for As, Cu, Cd, Cr, Fe, Pb, Ni, Mn, and Hg by using atomic absorption spectrophotometer. It was found that the concentration of trace metals namely As, Cu, Cd, Cr, Pb, Ni, and Hg in river water, sediment, snail and fish samples in Pahang River were lower than the maximum allowable limits, except for Fe and Mn. In Kelantan River, the concentration of trace metals indicating that it is contaminated with Fe, Mn, Pb, Cr, Cu, Hg, and As as all trace metals exceeded the maximum allowable limits. Negative impacts may arise, and the river may contaminate more in future if there is no proper management to tackle this issue during execution of dredging activities

Correlations between cancellous bone architecture and its dynamic behaviour

Previous studies showed that in vivo evaluation of the fracture risk of cancellous bone can be assessed by identifying the relationships between its microarchitecture description extracted from clinical imaging and its mechanical properties. The mechanical properties under dynamic loadings (with and without confinement) were obtained and compared to quasi-static ones. The architectural parameters of each specimen were extracted from pQCT images and split into four groups: geometry, topology, connectivity and anisotropy. Results show that architectural parameters are strong determinants of mechanical behaviour for the different applied boundary conditions.http://icills2014.org/wp-content/uploads/2014/01/Marrianne-Prot.pd

Pengaruh Locus of Control dan Financial Literacy terhadap Saving Behavior

Penelitian ini bertujuan untuk mengetahui pengaruh locus of control dan financial literacy terhadap saving behavior. Jenis penelitian ini menggunakan metode analisis konfirmatori yang bersifat kausalitas.  Sampel pada penelitian ini adalah 100 responden dan menggunakan teknik perhitungan slovin. Pengumpulan data dilakukan pada bulan Januari 2020. Data yang digunakan adalah primer dengan menggunakan pengukuran skala likert 5 point. Data dikumpulkan dengan menyebarkan kuesioner baik secara langsung maupun secara online melalui Google questionnaire. Teknik analisis data deskriptif dan inferensial, dengan pengujian inferensial menggunakan Structural Equation Modelling (SEM). Hasil dari penelitian ini menunjukkan bahwa locus of control dan financial literacy berpengaruh positif signifikan terhadap saving behavior

Microclimate model for urban heat island simulation: a prediction tool extension to calculate the ambient temperature of building

Universiti Tun Hussein Onn Malaysia (UTHM) is a public university located at Parit Raja, Batu Pahat, which is categorized as a suburban area of Johor, Malaysia and is still in development progress. However, the quick pace of development leads to changing of land use from green surface to hard surface building blocks which tends to increase the temperature level and reduce outdoor comfort level of occupants in UTHM. In addition, the available software simulations that used currently for temperature monitoring is mostly too complicated for educated non-scientist such as urban planners and architects. This research objectives are to predict the ambient building temperature of reference area by using Screening Tool for Estate Environment Evaluation software (STEVE) and to provide comparison for both of field measurements with STEVE results. In order to achieve these objectives, a total of six stations considering different urban morphologies are evaluated to give a better understanding on implication of urban heat island. The daily minimum (Tmin), average (Tavg) and maximum (Tmax) air temperature for six stations in UTHM have been developed and validated based on a long-term field measurement. The pavement (PAVE), building (BDG), green plot area ratio (GnPR), average height area (AvgHT), sky view factor (SVF), total wall area (WALL) and result of the temperature (Tmax, Tmin and Tavg) are automatically calculated by STEVE from the developed 3D models. The results show that the percentage different of temperature between STEVE and field measurement is in a range of 0.9-1.0% and this has strongly indicated that STEVE is suitable to be used as temperature prediction tool

Effect of Including Periodic Boundary Condition on the Fatigue Behaviour of Cancellous Bone

Trabecular bone consists of complex webbing of plates and struts, in which the properties vary across anatomical sites. The substantial constraint is the reduction on discretization error will reduce time in computation. So it is significant to consider carefully the boundary condition effects when utilizing such a complex multiaxial loading mode. Additionally, multiaxial loading gives distinct effects towards boundary condition compare to uniaxial whereas percentage prediction of fatigue failure is lower and applying of periodic boundary reflect a more precise real loading condition. 3D models of trabecular samples were constructed for FE simulations. The response of the models towards simulated mechanical loading was investigated. Preparation of the models begins with 3D reconstruction of micro-CT stacked images, follows by segmentation, meshing and refurbishing process. The resistance of trabecular bone deformation to loading in both uniaxial and multiaxial modes improved the fatigue life and failure with application of periodic boundary conditions

Development of CAVLAB—A Control-Oriented MATLAB Based Simulator for an Underground Coal Gasification Process

The Cavity Simulation Model (CAVSIM) is a 3D, parameterisable simulator of the Underground Coal Gasification Process (UCG) that serves as a benchmark for UCG prediction. Despite yielding accurate outputs, CAVSIM has some limitations, which chiefly include inadequate graphical capabilities to visualise cavity geometry and gas production, time-ineffectiveness in terms of parametrisation, i.e., it involves editing, compiling multiple files and checking for errors, and lack of tools to synthesise a controller. Therefore, to compensate for these shortcomings, the services of third-party software, such as MATLAB, must be procured. CAVSIM was integrated with MATLAB to utilise its functionalities and toolboxes such as System Identification, Neural Network, and Optimization Toolbox etc. The integration was accomplished by designing C-mex files, and furthermore, the simulation results in both environments exhibit the same behaviour, demonstrating successful integration. Consequently, CAVSIM has also acquired a controllable structure, wherein parametrisation is now a single-click process; this is demonstrated by a case study outlining the implementation of Model Predictive Control (MPC) on a UCG plant. Moreover, the performance metrics, i.e., Mean Average Error (MAE) and Root Mean Square Error (RMSE) of 0.13, 0.23 for syngas heating value, and 0.012, 0.02 for flowrate quantitatively establishes the efficacy of CAVLAB in designing MPC for the UCG system. The novelty of this work lies in making the software package open-source with the aim of streamlining the research of multiple aspects of the UCG process