Experimental Investigation of Vertical Density Profile of Medium Density Fiberboard in Hot Press

This research investigates the performance of medium density fiberboard (MDF) with respect to hot press parameters. The performance of the board, type of glue, and production efficiency determine the optimum temperature and pressure for hot pressing. The actual temperature of the hot press inside the MDF board determines the properties of the final product. Hence, the optimal hot press parameters for the desired product are experimentally obtained. Moreover, MDF is experimentally investigated in terms of its vertical density profile, bending, and internal bonding under the various input parameters of temperature, pressure, cycle time, and moisture content during the manufacturing process. The experimental study is carried out by varying the temperature, pressure, cycle time, and moisture content in the ranges of 200–220 °C, 145–155 bar, 260–275 s, and 8–10%, respectively. Consequently, the optimum input parameters of a hot-pressing temperature of 220 °C, pressure of 155 bar, cycle time of 256 s, and moisture content of 8% are identified for the required internal bonding (0.64 N/mm2), bending (32 N/mm2), and increase in both the core and peak density of the vertical density profile as per the ASTM standard.

Performance Comparison of Advanced Transcritical Power Cycles with High-Temperature Working Fluids for the Engine Waste Heat Recovery

To efficiently recover the waste heat of mobile engine, two advanced transcritical power cycles, namely split cycle and dual pressure cycle, are employed, based on the recuperative cycle. Performances of the two cycles are analyzed and compared through the development of thermodynamic models. Under given gas conditions, seven high-temperature working fluids, namely propane, butane, isobutane, pentane, isopentane, neopentane, and cyclopentane, are selected for the two cycles. At the design system parameters, the highest work 48.71 kW, is obtained by the split cycle with butane. For most of fluids, the split cycle has a higher work than the dual pressure cycle. Furthermore, with the increase of turbine inlet pressure, net work of the split cycle goes up firstly and then decreases, while the work of dual pressure cycle increases slowly. For the split cycle, there exists a split ratio to get the maximum network. However, for the dual pressure cycle, the larger the evaporation temperature, the higher the net work. On this basis, system parameters are optimized by genetic algorithm to maximize net work. The results indicate that the highest work 49.96 kW of split cycle is obtained by pentane. For the considered fluids, except cyclopentane, split cycle always has a higher work than dual pressure cycle. Due to the higher net work and fewer system components, split cycle is recommended for the engine waste heat recovery.

Hydroxy Gas (HHO) Supplement of Ethanol Fuel Mixture In A Single-Cylinder Spark-Ignition Matic-Engine

<p class="TTPAbstract">Hydroxy Gas (HHO) has been identified as an efficient alternative energy source. HHO is considered an alternative fuel. It can be applied alone or mixed with other kind of fuels in different ratios. In this analysis, the composition of HHO-ethanol was mixed in different variations. Ethanol-HHO was chosen because of its high-octane rating yet low exhaust emissions, and ease of obtaining from engine products. It has been applied on fuel prepared by mixing it with gasoline in various ratios (E30-HHO, E40-HHO, and E50-HHO). The ethanol-HHO mixture has been used in a single-cylinder 4-stroke spark machine for performance, by varying speed of engine from 4000 to 9000 RPM and by applying a platinum spark plug electrode type. In experiments, engine power, average effective pressure (MEP), specific fuel consumption (SFC), and thermal efficiency have been analyzed. The analysis of combustion is accomplished by taking a pressure cycle in the chamber, monitoring the automatic control of engine control unit (ECU) and ensuring utilization in the same parameters of the various fuels tested, in addition to the fuel injection time, which increases with increasing ethanol percentage. Optimal power, MEP and thermal efficiency values are obtained with ethanol-gasoline (E50-HHO) mixture which is operated at 7200 rpm, an increase of about 5% compared to gasoline. Significant reduction in SFC was observed using HHO-ethanol mixture, reduced by about 6% compared to gasoline.</p>

Communication and Mitigation Strategies Related to the Leading Indicator of Pressure Cycle Fatigue

Pressure cycle fatigue has been shown in industry to be a contributing factor to pipeline failure. There are methods for pressure cycle fatigue monitoring that can be used as a leading indicator for the risk of the pipeline to fatigue related failure. Once lines with high cycling are identified, the risk of the cycling to the asset and the mitigation strategies for the cycling can be discussed within the organization. By mitigating the driving force of crack initiation and grow to failure in-service, the pipeline community is safer. Shell Pipeline Company, LP. (SPLC) experienced two in-service failures on the same pipeline in under a year where fatigue was a common root cause. Following the investigation of these failures, management requested communication of the risk of pressure cycle fatigue throughout the organization with the intent to mitigate the levels of pressure cycling across the system. All pipelines were put on a monthly dashboard of pressure cycling and sent to all staff for awareness and action. The company measures pressure cycling on all pipelines by normalizing the number of cycles to 25% of the specified minimum yield strength (SMYS). From January 2016 to December 2019, the number of monthly cycles on the top ten highest cycled segments were reduced from 45,000 cycles per month, to 18,970 cycles. This is a reduction of 58%. The number of Very Aggressively cycled pipelines was reduced from 2 to 0. The number of Aggressively cycled pipelines were reduced from 13 to as low as 3. This paper will share the strategies and methodologies used to achieve these results. The paper will share how the list of highly cycled pipelines and the monthly status reports were developed. The paper will also share how pressure cycling mitigation strategies for pipeline systems were developed in collaboration with facility engineering, business unit leads, controllers, schedulers, and integrity staff. The effectiveness of mitigation methods such as pressure reduction, installation of back-pressure control valves, changing of valve timing on startup and shutdown, changes to the scheduling on the pipeline, utilization of flying switch between tankage, etc. will be discussed. By reducing pressure cycling, the risk of fatigue related failures can be reduced. This program is continuously being improved because there is both management commitment and ownership of the issue throughout the organization.

An Improved Methodology for Prioritizing Pipelines With Respect to Fatigue Cracking of Seam Weld Flaws

The threat of pressure cycle induced fatigue cracking of flaws associated with the longitudinal seam weld continues to be a primary concern for pipeline operators. Cyclic pressure loading can cause initial manufacturing flaws in a seam weld to sharpen and grow over time. While this behavior is most prevalent in pre-1979 electric resistance welds (ERW) and electric flash welds (EFW), historical data also shows that submerged arc welds (SAW) have been observed to develop cracks at the toe of the weld, and those cracks have exhibited fatigue growth from transit fatigue, operating pressure cycles, or both. When managing a large pipeline network, it is important to understand which pipelines exhibit higher priority with respect to seam weld fatigue cracking. While there are industry-accepted methodologies used to prioritize pipelines with respect to seam weld integrity (TTO-5 [1] and API RP 1176 [2] being the most well-known), these methodologies can be improved upon when specifically considering fatigue. Saudi Aramco and Quest Integrity developed a detailed methodology to determine a prioritization for a group of pipelines specifically with respect to seam weld fatigue cracking. This improved methodology was specially tailored to consider additional data available in Saudi Aramco’s records to rank the likelihood for a fatigue failure to occur. This initial prioritization will be used to implement a more rigorous program to manage their assets. Additional data gathered in subsequent assessments can be included to refine the prioritization. The primary metrics used to determine the prioritization are pressure cycle aggressiveness, predicted remaining life with respect to recent hydrostatic testing, and the API 1176 Annex B prioritization classification.