Abstract- Since the defects causes high rejection rates, it is important to move any production process in the direction of eliminating all imperfections as a part of an effective continuous improvement program. Forging process is no exception to this. In present study, the various forging defects that occur in the components during closed-die hot forging process are investigated initially. The investigation is done with the help of Quality Assurance department in a forging industry. During investigation, the various defects that causes high rejection rates are identified and unfilling defect which has major contribution in high rejection rate is selected for study purpose. The fish-bone diagram is used to explore the possible causes of unfilling defect, through a brainstorming session. It is observed that the three process parameters having major responsibility to fill the job weight. These parameters are- billet weight, heating temperature, and heating time. The best combination of these process parameters must be followed during the production process in order to reduce the rejection rate due to unfilling forging defect. To get the best parameter combination, DOE technique (like Taguchi method) is the most powerful approach. But before going to use Taguchi method, it is very much necessary to determine the effect of selected process parameters on output. Therefore, the objective of this paper is to present the effect/influence of selected process parameters on filling the job weight. For this purpose, OVAT analysis is used here. Engineers and Scientists often perform OVAT experiments, which consists of varying only one factor or variable at a time with keeping others constant.
Dedio and Dornel (1977) found that increasing the moisture content of flake seed from 8 to 16% decreases oil yield. At higher moisture level mucilage is developed in the outer cell and the addition of more water causes swelling of the mucilage and this produces a cushioning effect which prevents the rupturing of the oil cells. Oil point pressure indi- cates the threshold pressure at which oil emerges from a seed kernel during mechanical oil expression (Ajibola et al., 2002; Faborode and Favier, 1996). The effective pressure to be applied to an oil seed for the oil-bearing cells to start discharging their contents is determined by first identifying its oil point pressure. This helps to optimise the pretreatment and pressing operation for efficient oil expression from that seed. For most seed kernels, oil point pressure is determined by varying the heating temperature, heating time, moisture content and applied pressure (Ajibola et al ., 1993; Owola- rafe et al., 2003; Sukumaran and Singh, 1989). The optimal condition at which the oil point pressure of an oil seed is identified improves the oil expression efficiency and provi- des useful information for design and performance evalua- tion of oil expellers (Mrema and McNulty, 1985). This study was therefore undertaken to investigate the effects of some processing conditions such as moisture content, heating temperature, heating time and particle size on the oil point pressure of cashew kernel.
from the kinetic desorption experiments in this study is shown in Figure 3. Similar to the study of PEG-based hydrogel membrane coating by Ju et al., the NaCl diffusion coefficient, Ds, for each membrane was calculated from the slope of the linear portion of the desorption curve using Eq.(2). Table 2 presents the salt transport properties of hybrid membranes as a function of heat treatment conditions. NaCl solubility decreased with increasing heating temperature or time. The results agree well with the water uptake data (Figs. 1&2). In theory, no salt (NaCl) is expected to dissolve in a pure polymer matrix, so any NaCl in the membrane phase is assumed to be solvated by the water within the membrane . Therefore, the amount of NaCl in the membrane will be closely connected to the amount of water in the membrane. With increasing heating temperature or time, the swelling degree in the membrane decreases, and as a result, there is a tendency to accommodate less NaCl along with water in the membrane. It is expected that this low NaCl solubility would lead to low permeability and subsequent high rejection of NaCl through this membrane.
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Pyrolysis of sandbox shell was carried out with the aim of investigating the effect of pyrolysis parameters on the pyrolysis process and identifies production conditions for the yield of biochar. Parameters investigated were heating temperature (400, 500 and 600°C), heating time (10, 20, and 30 min) and particle size of feedstock (0–1.0, 1.0–2.5 and 2.5–5.0 mm) in a laboratory batch pyrolysis process. The experiment was designed by applying response surface methodology through a three-factor full factorial design. The quadratic polynomial model obtained explains adequately the modelled response with coefficient of correlation, R 2 value of 0.8698. All the three variables significantly affected the biochar
Figure 1 shows the thermogravimetry curve of merbau heartwood. The mass loss is about 5.0 % when the heating temperature is lower than 100 °C. The mass loss was due to the evaporation of water although the ground Merbau heartwood powder was oven dried before con- ducting the thermal analysis. Traces of the mass loss can be observed when the heating temperature is between 100 and 200 °C. Merbau heartwood remains thermally stable in this temperature range. The mass loss rate increases fast when the heating temperature exceeds 200 °C due to the thermal decomposition occurring in the hemi-cellulose and cellulose . A conclusion can be drawn that the heat treatment should be conducted below 200 °C, considering the thermal degradation of the mer- bau heartwood.
Agriculture industry in Malaysia has evolved entirely over the last decade due to the advancement in science and technology. Also, Malaysia’s mushroom industry has also shown an upward trend recently. Thus, the increasing of mushroom production in Malaysia also has led to the increasing of mushroom waste such as the spent mushroom substrate (SMS). It is estimated that for 1 kg of mushrooms grown, about 5 kg of SMS is produced. Since the SMS has high potential to be converted into activated carbon (AC) by pyrolysis method and chemical activation, thus this study is crucial to produce the AC derived from the SMS to be used in industrial application especially in the wastewater treatment as the AC has a very excellent adsorption property. Using AC from SMS, 93.7% of sulfide from the industrial wastewater was successfully removed. The optimum condition to produce AS was at the heating temperature of 515°C and heating time of 106 min.
Vegetable oils have been a universal demand due to their high rate of uses both domestically and industrially. There are several methods of extracting vegetable oils as earlier mentioned. The mechanical oil extraction have some disadvantages that can reduce the quality and yield of oil extracted. The power requirement for motorized screw press is high and its operation is very tedious and its components are bulky; also, the hydraulic oil from hydraulic press can spill into the extraction medium, which will contaminate the needed oil and could change its chemical composition. Likewise, some of the chemicals (solvents) for extracting oils during solvent extraction can mix with the needed oil; this may be very difficult and expensive to separate, and the presence of such chemicals in the extracted oils could lead to some adverse effects in the body when consumed or formation of unpleasant compounds when used to make other products. Furthermore, the traditional method of oil extraction is full of drudgery and the output is very low. In order to reduce some of the aforementioned problems, the use of a U-channel screw jack to extract vegetable oil was considered. Therefore, the main objective of this research was to develop a U-channel screw jack for vegetable oil extraction. The specific objective was to investigate the effect of two process conditions (heating temperature and heating time) on the performance indices (oil yield, extraction loss and extraction efficiency) of the machine.
Microwave duration also affected oil yield. Oil yield deceased with an increase in the microwave time. There was a lower decrease in oil yield from 2 to 3 min but the oil yield decreased more after 3 min of microwave treatment. Kittiphoom and Sutasinee (2015) observed that oil yield increased significantly when microwave pretreatment times was increased from 0 to 60 s however, further increase in microwave pretreatment time from 90-150 s for microwave power did not show any significant improvement. But Azadmard-Damirchi et al., (2010) and Uquiche et al., (2008) reported that increasing the treatment time also had a positive effect on the oil extraction yield for rapeseed and Chilean hazelnut. The residual oil percent was significantly affected by moisture content, heating temperature and microwave treatement. 3.4 Microwave roasting effects on physical and chemical properties of canola oil
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Thermoluminescence materials are being widely used in personnel and clinical dosimetry and also for environmental monitoring. And any reliable dosimetric study of new thermoluminescent material should include the determination of kinetic parameters namely order of kinetics, activation energy and frequency factor. To obtain these parameters from TL glow cur ves, different techniques are developed for which heating rate is one of the most important variables. It has been found that different heating rates cause different TL intensities which in turn may give rise to change in the trapping parameters.
The initial condition of the model is a magnetic strand (loop) in static equilibrium. This is obtained by starting with an ex- tremely high resolution uniform grid with 5 × 10 5 grid points along the length of the loop. We consider both a short (60 Mm) and long (180 Mm) loop, where the total length of each loop (2L) includes a 5 Mm model chromosphere (included as a mass reser- voir) at the base of each TR (z = 5 Mm). We set T = 10 000 K and n = 10 17 m −3 at the base of the TR. The initial equilib- rium temperature and density profiles are then derived using the same approach as described in Bradshaw & Mason (2003). We note that, to achieve thermal balance, a small background heat- ing term is necessary (Q bg ). These fully resolved equilibrium so-
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Woodceramics are superior to the original wood in thermal resistance, and because they are porous, their density is normally about 1.0 Mg m 3 , i.e., about the same as that of epoxy resins or polyethylene resins, and about one third of that of widely used ceramics such as alumina. Physical properties of woodceramics diﬀer depending on the starting material and sintering temperature, however, it is now well established that woodceramics based on medium-density ﬁberboard of satisfactory strength (3.1 GPa Young’s Mod- ulus, 24 MPa fracture strength) can be obtained by sintering at 800 C or higher. 2)
Fig (6) shows Coast-Redfern plot for different percentages of TCNP at constant heating rate 5 K/min again the data fits linearly, the kinetics parameter are extracted from Fig (6) are shown in Table (6) shows the activation energy increased as comparing with pure EP this indicates that TCNP increases thermal stability but at the same time fostering the reaction to produce the layer of char eventually protect EP from fire or heat, therefore the stability increases (17)
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cooling concept to social housing design in dry hot climate. They aim to ensure a certain comfort for the flats during the summer months by applying a passive solar cooling concept. By introducing an accessible high thermal mass in the building construction and activating it during the night with increased ventilation, the concept tries to limit the indoor temperature below an operative temperature of 28 °C, instead of using fan.
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strain and temperature, at central wavelength around 1550um, are: wavelength variations due to mechanical strain about 1 pm/µε and 10 pm/C°, respectively. Being wavelength encoded, FBG sensors allow distributed sensing over significant areas by multiplexing a large number of sensors on a single optical fiber and have compact size; moreover optical signals are intrinsically immune to electromagnetic interference. Due to all these advantages, they have been widely used in many applications for the structural health monitoring .
The energy and load assessment of a swimming pool is quite a difficult task to be handled in full details due to several different parameters which should be considered in their design. These variables experience a time dependent fluctuation during the day and night time. The heat balance is also being affected by the place of pool installation whether it is indoor or outdoor and over-ground or underground. For outdoor pools, the heat balance of the pool is governed by the weather conditions such as solar radiation, air and sky temperatures, humidity and wind speed. Accordingly, the investigation outlines a rough assessment for the energy demand of the above-ground swimming pool with a margin of accuracy depends on the available correlations. Figure 1 shows a schematic diagram for the suggested system layout implemented for the heating purposes of the over-ground swimming pool.
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(iii) The amorphous state of the as-cast ribbon has been confirmed by XRD. The evolution of the primary crystallization phase on annealed samples has been confirmed as α-Fe(Si) and their sizes have been found from 50 to 69 nm. These facts reveal that heat treatment temperature should be limited with in 600 o C as grain size remains 50 nm to obtain optimum soft magnetic behavior, From XRD experiment, the crystallization onset temperature for the sample is found around 600 o C which coincides well with the value obtained from DTA.
They can either choose direct (DC) or alternating (AC) current, and consumable or non-consumable electrodes. The welding section is mostly shielded by some type of shielding gas, vapors, and slag. Finally about the heat treatment process, it can be assume as heat treatment where a material is altered, causing changes in its properties such as strength and hardness. It is a process that produces conditions by heating to above the recrystallization temperature, maintaining a suitable temperature, and then cooling.
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The distribution of surface temperature system is shown in Fig.7 when the system reaches steady state. It is obvious that the surface temperature of every support is different, and the maximum temperature difference is about 3.5℃, which shows that the uniformity of the surface temperature distribution is poor. This is related to the position of the measuring point. When the temperature measuring points are located above the pipe, the heat transfer is better and the temperature is higher. While the other points are located at the top of the two heating tube, the temperature is lower than the former.
ring International Institute of Refrigeration, it is estimated that 15% of electricity produced in a whole world is utilized for refrigerating and air conditioning systems. Currently, world demand of air conditioner trends to be continuously increased with estimated rate of 17%. Almost air conditioners has been used as type of vapor com- pression system which provides several disadvantages of consuming huge amount primary energy and CFC re- frigerant caused for ozone depletion. The development in refrigeration system assisted by alternative energy such as solar heat and waste heat has been happened. Especially, hot climate region such as Thailand, there have been utilization of solar driven refrigeration systems for industrial, transportation and residential sectors. Exam- ples of refrigeration technologies, which can be assisted by solar heat, are absorption, adsorption, evaporative ejector etc. From comparative performance study of thermal refrigeration technologies, absorption type yields the highest system performance ranging from 0.7 - 0.8 while system has high complex and can generate crystal- lization problem of salt solution or working pair at high generator temperature and concentration. While the ejector type seems more interesting for using single refrigerant, the system has a difficulty of ejector design to obtain high ejector and system performance. Adsorption refrigeration system is one of attractive system because the system provides a little amount of components and non-complex configuration. Additionally, Activated car- bon (AC)/CH 3 OH is commonly used as working pair because of its cheap cost and availability. There are no
Thirteen thermocouples were secured onto the refrigerant loop indicated in Fig. 1 and two thermocouples were secured onto the water loop of the experimental set-up. More thermocouples were installed on the condenser and evaporator to determine the average condensing and evaporating temperatures. The experimental systems were left to operate for approximately 20 minutes until a steady state was reached for selected ambient temperatures. The appropriate measurements were then taken on the experimental set-up. The wet-bulb air temperatures were measured using a sling thermometer with an error of 0.2°C. The power absorbed by the compressor and fans were measured with a power harmonics analyser with an error of +1 W. The refrigerant enthalpy values for a heat exchanger were determined from the refrigerant inlet and outlet temperatures of the heat exchanger using a refrigerant database (NIST, 1993). The temperature readings (isotherm) of the two-phase regions were used to determine the evaporation and condensation temperatures. Care was taken to ensure an energy balance of less than ± 10% between the air or water and the refrigerant used. Experiments were conducted on the experimental set-up for cooling and heating cycles respectively.