Development of a high pressure compressed natural gas mixer for a 1.5 litre CNG-diesel dual engine

[Abstract]: The Computational Fluid Dynamics (CFD) analysis software was used to study the flow behaviour of compressed natural gas (CNG) and air in a CNG-air mixer to be introduced through the air inlet of a CNG-Diesel dual fuel stationary engine. The results of the simulation show that the Venturi mixer with more holes gives superior engine performance compared to the 4-hole Venturi mixer. Further analysis is done on the different holes mixer to investigate the effect of engine speed on the mass flow rate of CNG and the equivalence ratio Lambda. The second part of the paper represents a comparison results between the performances of a single cylinder research Compression Ignition CI engine fuelled with CNG-diesel system and conventional CI engine fuelled by conventional diesel. The engine was equipped with the simulated Venturi mixer, the result showed significant reduction in the exhaust gas emission compared to the conventional diesel engine. The average power output generated by dual fuel engine was slightly higher than that diesel one at different engine speeds

An Uncommon Cause of Acute Bowel Obstruction: The Left Para.Duodenal Hernia

Internal hernias of the abdomen are uncommon. They represent less than 1% of bowel obstruction cases. The left Paraduodenal hernia (PH) is the most frequent type of internal hernias. We report a case of 77 year- old woman consulting for bowel obstruction evolving since two days. The abdominal computed tomography revealed a retroperitoneal small bowel contained in a peritoneal sac. The surgical exploration confirmed the diagnosis of a left internal PH by showing incarcerated jejunal loops in a PH through a narrow opening to the left of the angle of Treitz. A surgical reduction of the hernia and closure of the hernia neck were performed. The follow-ups were uncomplicated. Through this observation and a literature review, we try to recall the clinical and radiological characteristics of this disease and toclarify the therapeutic modalities.Keywords: Computed tomography, internal hernia, paraduodenal hernia, small bowel obstructio

Filament winding technique, experiment and simulation analysis on tubular structure

Filament winding process has emerged as one of the potential composite fabrication processes with lower costs. Filament wound products involve classic axisymmetric parts (pipes, rings, driveshafts, high-pressure vessels and storage tanks), non-axisymmetric parts (prismatic nonround sections and pipe fittings). Based on the 3-axis filament winding machine has been designed with the inexpensive control system, it is completely necessary to make a relative comparison between experiment and simulation on tubular structure. In this technical paper, the aim of this paper is to perform a dry winding experiment using the 3-axis filament winding machine and simulate winding process on the tubular structure using CADWIND software with 30°,45°,60° winding angle. The main result indicates that the 3-axis filament winding machine can produce tubular structure with high winding pattern performance with different winding angle. This developed 3-axis winding machine still has weakness compared to CAWIND software simulation results with high axes winding machine about winding pattern, turnaround impact, process error, thickness, friction impact etc. In conclusion, the 3-axis filament winding machine improvements and recommendations come up with its comparison results, which can intuitively understand its limitations and characteristics

Polypropylene Reinforced With Recycle Polyethylene Terephthalate As An Alternative Material For New Plastic Product

Polyethylene Terephthalate (PET) is one of the most important fibers for industrial application. High performance, low cost, and recyclables are the most attractive candidates for high strength fibers. This paper presents the best ratio of Polypropylene (PP) reinforced with recycle PET fiber, as an alternative material for new plastic product. It gives the high strength of Polypropylene reinforced with recycle PET fiber. PP was mixed with recycle PP fiber utilising the plastic mixer and injection mold machine. The samples were cut according to ASTM standard and tested by using universal testing equipment. The analyses were carried out by using 0% ~ 10% volume compositions of recycle PP fiber. The acquired results indicate that the composition of PP gives higher ultimate tensile strength. It can be seen that the strength of PP increases in the presence of PET. It reduces the manufacturing cost and uses as an alternative material to PP for industrial application

The non-admissibility of the principle of therapeutic privilege in clinical trials

The objective of this paper is to examine the issue of non-admissibility of the principle of therapeutic privilege in clinical trials.In medical treatment, doctors could decide not to disclose information for the best interest of the patients by adopting the principle of therapeutic privilege.This principle exempts doctors from disclosing risky information at his discretion especially if by doing so will cause harm or trauma to patients.However, this principle is not recognised in clinical trials. Instead, the need to obtain patient’s consent by way of informed consent has been mandatorily imposed as a way to protect the patients.The doctor-investigator must disclose full information pertaining to the trial to the patient.This paper is a library based collating literature review data. Qualitative methodology and analysis were used in this paper. This paper revealed that despite the fact that the principle of therapeutic privilege has not been recognised in clinical trials, the attitude of patients that placed high hopes on doctor-investigator has indirectly encouraged the latter not to disclose information by adopting this principle.This paper implies that the doctor investigator practices the principle of therapeutic privilege, an act of paternalism that has been brought into the process of consent taking in clinical trials.In conclusion, the Good Clinical Practice Training Curriculum by the Ministry of Heath Malaysia is suggested to be improvised and further enhanced

A quasi-brittle damage model in the framework of bond-based peridynamics with adaptive dynamic relaxation method

Peridynamics (PD) is a new tool, based on the non-local theory for modelling fracture mechanics, where particles connected through physical interaction used to represent a domain. By using the PD theory, damage or crack in a material domain can be shown in much practical representation. This study compares between Prototype Microelastic Brittle (PMB) damage model and a new Quasi-Brittle (QBR) damage model in the framework of the Bond-based Peridynamics (BBPD) in terms of the damage plot. An in-house code using Matlab was developed for BBPD with inclusion of both damage models, and tested for a quasi-static problem with the implementation of Adaptive Dynamic Relaxation (ADR) method in the theory in order to get a faster steady state solutions. This paper is the first attempt to include ADR method in the framework of BBPD for QBR damage model. This paper analysed a numerical problem with the absence of failure and compared the displacement with literature result that used Finite Element Method (FEM). The obtained numerical results are in good agreement with the result from FEM. The same problem was used with the allowance of the failure to happen for both of the damage models; PMB and QBR, to observe the damage pattern between these two damage models. PMB damage model produced damage value of roughly twice compared to the damage value from QBR damage model. It is found that the QBR damage model with ADR under quasi-static loading significantly improves the prediction of the progressive failure process, and managed to model a more realistic damage model with respect to the PMB damage model

Effect of particle discretisation and horizon size on the displacement and damage plot using bond-based peridynamics

Peridynamics (PD) represents a new non-local theory of continuum mechanics which uses integro differential equations instead of the typical local partial differential equations in its formulation. Thus, it is suitable for modelling fracture mechanics, where a continuum domain is modelled through particles connected via physical interactions. The PD formulation allows us to model spontaneous crack initiation, and crack branching without the need for special mathematical treatment. The value of parameters such as particle discretisation and horizon size will be checked to make sure that it agreed to the result from Finite Element Method (FEM) in elastic deformation before proceed to the failure mode. In PD, failure criterion is established when its stretch value exceeds a prescribed critical stretch value. In the classical bond model or Prototype Microelastic Brittle (PMB), the bond force grows linearly with the bond stretch, and the value suddenly goes down to zero when the bond stretch exceeds its critical value. This study will focus on the effect of horizon size and particle discretisation on PD displacement of elastic analysis, and damage patterns with PMB damage model. The proposed study leads to a better understanding of how horizon size and particle disretisation affect the damage patterns in PD frameworks

Fracture response of La61.4Al15.9Ni11.35Cu11.35 bulk metallic glass subjected to quasi-static compression loading

Lanthanum based bulk metallic glass (BMG) is one of the BMG which have the excellent glass-forming ability (GFA). In this empirical study, as-received La61.4Al15.9Ni11.35Cu11.35 bulk metallic glasses were subjected to a quasi-static compression test. The results show the maximum modulus Young’s of 191 GPa, the compressive force of 590 MPa and the compressive displacement at maximum force of 0.35 mm. The La-based BMG were comparable to the 304 stainless steels in term of the mechanical properties. The La-based BMG fracture response from the quasi-static compression test was documented. The fracture response under compressive loading is vital to understand the La-based BMG for the promising used in lightweight alloy applications. identity

A brief review of the cubic star on structural design, applications, and future perspective

With the increasing diversification of space missions, the cube star, as a standard module-based miniature spacecraft, has gradually become increasing research interest and development in the field of aviation based on its low cost, high integration, and short development cycle. This paper reviews the design, application, and prospect of cube star, which analyzes the standardized structural design, attitude system, power system, communication measurement, and control design. It is focused on the application areas of cube star in demodulation of satellite signals, space exploration, and discovery technology verification, earth observation, communication interruption, etc. Finally, the development trend of future cube star technology is analyzed