In order to obtain better quality cookies, food 3D printing technology was employed to prepare cookies. The texture, color, deformation, moisture content, and temperature of the cookie as evaluation indicators, the in...In order to obtain better quality cookies, food 3D printing technology was employed to prepare cookies. The texture, color, deformation, moisture content, and temperature of the cookie as evaluation indicators, the influences of baking process parameters, such as baking time, surface heating temperature and bottom heating temperature, on the quality of the cookie were studied to optimize the baking process parameters. The results showed that the baking process parameters had obvious effects on the texture, color, deformation, moisture content, and temperature of the cookie. All of the roasting surface heating temperature, bottom heating temperature and baking time had positive influences on the hardness, crunchiness, crispiness, and the total color difference(ΔE) of the cookie. When the heating temperatures of the surfac and bottom increased, the diameter and thickness deformation rate of the cookie increased. However,with the extension of baking time, the diameter and thickness deformation rate of the cookie first increased and then decreased. With the surface heating temperature of 180 ℃, the bottom heating temperature of 150 ℃, and baking time of 15 min, the cookie was crisp and moderate with moderate deformation and uniform color. There was no burnt phenomenon with the desired quality. Research results provided a theoretical basis for cookie manufactory based on food 3D printing technology.展开更多
This paper investigated an experimental method for bake hardening properties, a technique for deriving the true stress-strain curves after reaching the maximum load, and a constitutive equation considering both work h...This paper investigated an experimental method for bake hardening properties, a technique for deriving the true stress-strain curves after reaching the maximum load, and a constitutive equation considering both work hardening and bake hardening in order to apply the work hardening occurring in the forming process of parts and the bake hardening induced in the baking process to an automotive crash simulation. A general bake hardening test is that a pre-tensioned specimen is baked and then the same specimen is tensioned again without any further treatment. For a bake hardening test of automotive steel with a tensile strength of 1.2 GPa or more, fractures often occur in curvature section outside, an extensometer due to the difference in the material strength caused by non-uniform bake hardening. This causes a problem in that the bake hardening properties cannot be obtained. In this paper, to prevent curvature fracture, tensile specimens were re-machined in the uniformly deformed region of large specimens subjected to pre-strain, and the re-machined specimens with uniform strength in all regions were re-tensioned. In the bake hardening test of ultra-high strength steels with a tensile strength of 1 GPa or more, shear band fractures occur when the pre-strain is large. This makes it impossible to obtain a true stress-strain curve because there is no uniformly deformed region under a tensile test. To overcome this problem, a new method to calculate the true stress-strain curve by comparing experimental results and the load calculated by the local strain obtained from digital images was developed. This method can be applied not only where shear band deformation occurs, but also in necking deformation, and true stress-strain curves for strains up to 2 - 3 times the uniform elongation can be obtained. A new constitutive equation was developed since an appropriate hardening model is required to simultaneously apply the work hardening and the bake hardening to the simulation. For the newly developed model, the user material subroutine of LS-Dyna was configured, and the simulation was performed on the single hat specimens with pre-strain. When both work hardening and bake hardening were considered, there was a significant increase in absorbed energy compared to when only work hardening was considered. This means that both work hardening and bake hardening should be considered in the car crash simulations to enhance the accuracy of the simulation.展开更多
A cold method was used to prepare coated sand for application in the selective laser sintering(SLS)process.Tensile strength,loss on ignition,gas evolution,and accuracy of the SLS samples were tested and analyzed,and t...A cold method was used to prepare coated sand for application in the selective laser sintering(SLS)process.Tensile strength,loss on ignition,gas evolution,and accuracy of the SLS samples were tested and analyzed,and the baking process was thoroughly investigated.Compared with coated sand prepared by the hot method,the cold method yields a more uniform and complete resin film on the sand's surface,resulting in enhanced tensile strength and accuracy.Additionally,the cold method requires a lower binder content to meet the same strength requirements,thereby minimizing gas evolution,reducing porosity defects,and ultimately improving casting quality.The coated sand samples prepared through the cold method exhibit superior accuracy,with a size error of within±0.4 mm.In contrast,the coated sand samples prepared by the hot method display a lower accuracy,with an average negative error of 2.1993 mm.The highest tensile strength could be attained by controlling the baking temperature within a suitable range(180-190°C),which can effectively reduce the generation of gas,thus contributing to improved overall performance.展开更多
The study investigates the effects of pre-strain on the bake hardenability and precipitation behavior of Al-Mg-Si automotive body sheets. The scanning electron microscopy, transmission electron microscopy, tensile tes...The study investigates the effects of pre-strain on the bake hardenability and precipitation behavior of Al-Mg-Si automotive body sheets. The scanning electron microscopy, transmission electron microscopy, tensile test, Vickers hardness test, and differential scanning calorimetry were conducted for the purpose. It was found that the pre-strain treatment partially inhibits the natural aging hardening effect but cannot completely eliminate it. The pre-straining significantly enhances the bake hardening effect, with the 5% pre-strain sample showing the highest increase in yield strength and hardness. The formation of fine β" precipitates and dislocation structures contribute to the observed strengthening. Additionally, the study highlights the importance of optimizing pre-strain levels to achieve the best balance between strength and ductility in bake-hardened aluminum alloys.展开更多
The effects of copper on the ageing precipitation behavior of as-quenched and pre-aged AA6016 aluminum alloy were studied by differential scanning calorimetry (DSC), Vickers hardness measurement and transmission ele...The effects of copper on the ageing precipitation behavior of as-quenched and pre-aged AA6016 aluminum alloy were studied by differential scanning calorimetry (DSC), Vickers hardness measurement and transmission electronic microscopy (TEM). The results indicate that the addition of copper facilitates the growth of clusters (GP I) to the critical size during pre-ageing. Therefore, the addition of copper accelerates the transition from GP I (pre-β") to GP II (β") during final artificial ageing, and finally results in the favorable paint-bake response. However, the one with the copper level of 0.3% does not show significant baking hardening response as expected. Pre-aging can also reduce the detrimental effect due to natural aging of copper-containing alloys.展开更多
In a typical process, C-Mn steel was annealed at 800℃ for 180 s, and then cooled rapidly to obtain the ferrite-martensite microstructure. After pre-straining, the specimens were baked and the corresponding bake-harde...In a typical process, C-Mn steel was annealed at 800℃ for 180 s, and then cooled rapidly to obtain the ferrite-martensite microstructure. After pre-straining, the specimens were baked and the corresponding bake-hardening (BH) values were determined as a function of pre-strain, baking temperature, and baking time. The influences ofpre-strain, baking temperature and baking time on the microstructure evolution and bake-hardening behavior of the dual-phase steel were investigated systematically. It was found that the BH value apparently increased with an increase in pre-strain in the range from 0 to 1%; however, increasing pre-strain from 1% to 8% led to a decrease in the BH value. Furthermore, an increase in baking temperature favored a gradual improvement in the BH value because of the formation of Cottrell atmosphere and the precipitation of carbides in both the ferrite and martensite phases. The BH value reached a maximum of 110 MPa at a baking temperature of 300℃. Moreover, the BH value enhanced significantly with increasing baking time from 10 to 100 min.展开更多
Pitch and TiB2/C green composite cathode material were respectively analyzed with simultaneous DSC-TGA, and effects of three baking processes of TiB2/C composite cathode material, i.e. K25, K5 and M5, on properties of...Pitch and TiB2/C green composite cathode material were respectively analyzed with simultaneous DSC-TGA, and effects of three baking processes of TiB2/C composite cathode material, i.e. K25, K5 and M5, on properties of TiB2/C composite cathode material were investigated. The results show that thermogravimetrie behavior of pitch and TiB2/C green composite cathode is similar, and appears the largest mass loss rate in the temperature range from 200 to 600 ℃. The bulk density variation of sample K5 before and after baking is the largest (11.9%), that of sample K25 is the second, and that of sample M5 is the smallest (6.7%). The crushing strength of sample M5 is the biggest (51.2 MPa), that of sample K2.5 is the next, and that of sample K5 is the smallest (32.8 MPa). But, the orders of the electrical resistivity and electrolysis expansion of samples are just opposite with the order of crushing strength. The heating rate has a great impact on the microstructure of sample. The faster the heating rate is, the bigger the pore size and porosity of sample are. Compared with the heating rate between 200 and 600℃ of samples K25 and K5, that of sample M5 is slower and suitable for baking process of TiB2/C composite cathode material.展开更多
In an anode baking horizontal flue ring furnace, the temperature distribution is one of the key factors influencing the quality of baked anode and is closely correlated with the gas flow. To understand the gas flow di...In an anode baking horizontal flue ring furnace, the temperature distribution is one of the key factors influencing the quality of baked anode and is closely correlated with the gas flow. To understand the gas flow distribution in the flue, Navier Stokes equation with " k ε " two equation turbulence model was adopted and the simulation on the gas flow was performed. The numerical simulation results showed that the even direction of gas flow should be considered in the design of flue baffles and the gas flow distribution was really uneven in the flue in practical use. By adjusting the number and location of flue baffles rationally, the even distribution of gas flow can be improved obviously.展开更多
Among the folate compounds, 5-methyltetrahydrofolic acid (5-CH3THF) is regarded as one of the most bioactive forms of folate. It is regarded as the better source of folate to humans as compared to folic acid, a synthe...Among the folate compounds, 5-methyltetrahydrofolic acid (5-CH3THF) is regarded as one of the most bioactive forms of folate. It is regarded as the better source of folate to humans as compared to folic acid, a synthetic form of folate, which is used for fortifying foods to prevent the incidence of neural tube defects in the new born babies. The use of 5-CH3THF as an alternative fortificant, in place of folic acid, has been explored by various researchers. However, fortification of 5-CH3THF is problematic due to its lower stability. This study investigated the stability of microencapsulated 5-CH3THF in biscuits baked at various temperatures and times as well as changes in their physical properties. Microcapsule with pectin and alginate ratio of 80:20, prepared by spray drying, gave the highest retention (68.6%) of the 5-CH3THF, therefore, chosen for fortification. The encapsulated and unencapsulated 5-CH3THF were mixed separately with flour and biscuit ingredients and baked at 180℃, 200 and 220℃, each for 5, 9 and 12 min. The inclusion of encapsulated and unencapsulated 5-CH3THF in the biscuit formulation and subsequent baking at various temperatures and times resulted in retention of 5-CH3THF from 19.1% to 1.7%. Microencapsulation of 5-CH3THF slightly improved the retention of 5-CH3THF over unencapsuated biscuits at 180℃ for 5 min, but almost no such effect was achieved under baking temperatures of 200℃ and 220℃. Physical analysis showed darker colour, harder texture and lower moisture content for biscuits baked at higher test temperatures. It seems intense heating condition that caused “over baking” of the biscuit likely to be responsible for the loss of the vitamin as well as less desirable physical properties of the biscuits.展开更多
The purpose of this study was to investigate the suitability of palm diacylglycerol (PDAG)-enriched formulations for bakery shortening. Three types of palm diacylglycerol olein (PDAGOL) at different degree of unsa...The purpose of this study was to investigate the suitability of palm diacylglycerol (PDAG)-enriched formulations for bakery shortening. Three types of palm diacylglycerol olein (PDAGOL) at different degree of unsaturation (PDAGOL1V56, PDAGOLIV62 and PDAGOLIV64) were used as main raw materials blended with palm stearin (PS). The blending compositions ranged from 30% to 70% of PDAGOLIV56/PS, PDAGOLIV62/PS and PDAGOLIV64/PS, respectively. The physicochemical properties of all binary blend systems were characterized for fatty acid composition (FAC), slip melting point (SMP) and solid fat content (SFC). The selected bakery shortening formulations were further characterised for polymorphic form of fat crystal and thermal behavior, using X-ray diffractometer (XRD) and differential scanning calorimetry (DSC). Bakery shortening enriched with diacylglycerol that were produced from 40DS56 (40% PDAGOLIV56/60% PS), 40DS62 (40% PDAGOL1V62/60% PS) and 40DS64 (40% PDAGOLIV64/60% PS) had 45%-50% unsaturated fatty acid and crystallized in β + β polymorphs; thus they were suitable for shortening system. Based on product's baking performance, it could be found that all Madeira cakes prepared from bakery shortening enriched with diacylglycerol had higher specific cake volume as compared to commercial shortening (CS). In customer acceptance test, Madeira cake made from 40DS56 shortening scored the highest rating for all sensory attributes, including overall customer acceptability. It had given an indication that 40DS56 shortening formulation was the most suitable fat blends to be used as bakery shortening.展开更多
The accumulation of protein fractions was analyzed on developing and mature wheat grains of three cultivars differing in protein content and baking quality. There was a slight difference in the accumulation of cytopla...The accumulation of protein fractions was analyzed on developing and mature wheat grains of three cultivars differing in protein content and baking quality. There was a slight difference in the accumulation of cytoplasmic proteins in the cultivars used. The high yield but low protein cultivar showed a consistent decline of protein content during grain filling but the high - protein cultivars increased their psotein contant after 25 days post-anthcsis. The accumulation of storage proteins was different from that of cytoplasmic protein, and there were also cultivar variations. However, all cultivars reached their, maximum-synthesizing capacity for storage proteins at maturity. The relationship between the protein fractions or their ratio and baking quality was also discussed.展开更多
Two experimental steels with tensile strength above 980 MPa were prepared to investigate the effect of prestrain and baking on their mechanical and fracture behaviors. The experimental results reveal that,for both exp...Two experimental steels with tensile strength above 980 MPa were prepared to investigate the effect of prestrain and baking on their mechanical and fracture behaviors. The experimental results reveal that,for both experimental steels,with increases in the prestrain level,the bake hardening value increases before reaching a maximum point,and then decreases with further increases in the prestrain level. The results of a "bending-baking-secondary bending"test indicate that the secondary bendability deteriorates at a high level of prestrain. The yield strength of the experimental steels was found to increase and the elongation to decrease after high levels of prestrain and bake hardening. Fracture morphology images indicate that a high prestrain level is associated with shallow dimples and more and larger local cleavage areas.展开更多
An existing small-scale single-powered baking oven was modified and optimize into a dual-powered oven. The oven was redesigned to accommodate the initially designed firewood heat source and the newly introduced gas he...An existing small-scale single-powered baking oven was modified and optimize into a dual-powered oven. The oven was redesigned to accommodate the initially designed firewood heat source and the newly introduced gas heat source. Four heat exchangers (thermal pipes) were introduced to the baking chamber for effective heat and mass transfer during baking of bread dough. The thermal pipes were made of 2 mm thick hollow galvanized steel pipe of 23 mm diameter and 660 mm length. The performance of the oven was evaluated using the standard performance index, which includes baking capacity, baking efficiency and weight loss of the baked bread. The baked bread’s physical properties were determined and analyzed using Duncan multiple range ANOVA test at significant level of <em>p</em> < 0.05. These properties were optimized to determine the generate regression models using 3D model plot. The baking capacity, baking efficiency, weight loss and optimum baking temperature were: 101.9 kg/h, 46.44% (wood-fired);70.34% (gas-fired), 13.5 g (wood-fired);and 25.5 g (gas-fired), 150<span style="white-space:nowrap;">˚</span>C, respectively. The physical properties of baked bread, wood-fired were found to correspond with that of gas-fired oven. The modified oven can be used for the baking of dough at domestic, small and medium scale bakery.展开更多
The baking industry is a part of the food industry. Since the beginning of the 1980s, China has carried out a strategy of developing instant foods. The baking industry has developed rapidly, and has introduced big cha...The baking industry is a part of the food industry. Since the beginning of the 1980s, China has carried out a strategy of developing instant foods. The baking industry has developed rapidly, and has introduced big changes in the structure of its varieties, quality of products, decoration of packages and technical equipment. So far, there are 4, 000 enterprises baking foods in China with 360, 000 staff and workers and an annual capacity of baked foods of two展开更多
In this paper, a 2D transient finite element analysis was carried out for a new type of solar powered injera baking system. In the proposed system (currently under development), heat transfer oil is heated using sol...In this paper, a 2D transient finite element analysis was carried out for a new type of solar powered injera baking system. In the proposed system (currently under development), heat transfer oil is heated using solar energy by parabolic trough and the oil circulates through the space below the baking pan in the kitchen. Based on previous finite element study on existing electric injera baking pans, a new type of baking pan made from ceramic with 8 mm thickness was manufactured and used for the proposed system. The model was further extended to study the heat up time and temperature distributions during initial heat up and cyclic baking of the new model. The proposed baking pan that uses solar energy gives acceptable heat up and baking time compared to existing conventional baking methods. Generally, the finite element model predicts well the temperature distributions during initial heat up and cyclic baking.展开更多
Gluten,the protein responsible for the superior viscoelastic properties of refined wheat flour dough over glutenfree cereals,causes celiac disease in people susceptible to gluten-allergy.Moreover,the sustainability of...Gluten,the protein responsible for the superior viscoelastic properties of refined wheat flour dough over glutenfree cereals,causes celiac disease in people susceptible to gluten-allergy.Moreover,the sustainability of using wheat flour in baked foods is threatened by its high cost,especially in countries that depend on imported wheat for their bakery industry.Research has shown that hydrocolloids serve as gluten replacements in baked foods,in response to these challenges.Food hydrocolloids are a class of high-molecular weight polysaccharides and proteins,which serve as functional ingredients in the food industry that modify the foods’rheological and textural properties.They function as stabilizers,viscosity modifiers,gelling agents,water binders,fibres,and inhibitors of ice crystal in foods.Further,food hydrocolloids have also been reported to possess health-promoting properties,such as lowering of postprandial blood glucose and plasma cholesterol concentrations,colon cancer prevention,and modulation of intestinal transit and satiety.They are obtained from plants,animals or microorganisms,and can be used in their natural or modified forms.The aim of this paper is to review the functional benefits of natural and modified hydrocolloids as gluten replacements in baked foods,emphasizing their physicochemical,nutraceutical,and sensorial importance.The application effects of food hydrocolloids as gluten substitutes in gluten-free baked products’quality were discussed.Also,some practical approaches to improve the quality of gluten-free baked products,in response to an increasing consumers’demand and the rising cost of refined wheat flour were highlighted.展开更多
Sodium bicarbonate is sometimes used to aid in the extraction of total polyphenols. Its main effect is to increase the pH of the extraction solution. Raising the pH can cause changes in the chemical structure of polyp...Sodium bicarbonate is sometimes used to aid in the extraction of total polyphenols. Its main effect is to increase the pH of the extraction solution. Raising the pH can cause changes in the chemical structure of polyphenols. This can lead to variations in their biological properties, solubility and stability. This work studied the effect of sodium carbonate on the extraction by aqueous decoction of total polyphenols from the leaves of Combretum micranthum. The content of total phenolic compounds in the extracts was estimated by the Folin-Ciocalteu method. The color of the samples was measured using a colorimeter (type: KONICA MINOLTA. Japan) based on the CIELAB color system. The results obtained were subjected to a one-way ANOVA analysis of variance with R software version 3.2.4 Revised (2018) and Minitab-18 software. The results reveal a drop in the concentration of extracted polyphenols proportional to the addition of sodium carbonate, i.e. a drop from 3.30 to 1.04 mg·AG·100 g<sup>-1</sup> of extract on whole leaves and 3.921 to 2.551 mg·AG·100 g<sup>-1</sup> extract on crushed leaves. On the other hand, the intensity of the coloring of the extracts increases significantly with the addition of sodium carbonate from 0.0 g·L <sup>-1</sup> to 0.666 g·L<sup>-1</sup>.展开更多
The influences of high temperature pre-straining (HT-PS) on the natural aging and bake hardening of Al?Mg?Si alloys were investigated by Vickers microhardness measurements, differential scanning calorimetry (DSC) anal...The influences of high temperature pre-straining (HT-PS) on the natural aging and bake hardening of Al?Mg?Si alloys were investigated by Vickers microhardness measurements, differential scanning calorimetry (DSC) analysis and transmission electron microscopy (TEM) characterization. The results show that pre-straining at 170 °C immediately after quenching can effectively resolve the rather high T4 temper hardness caused by the conventional room temperature (RT) pre-straining treatment, and give a better bake hardening response (BHR) after paint-bake cycle. HT-PS 7% at 170 °C for 10 min is chosen as the optimum process as it provides lower T4 temper hardness and better BHR. The simultaneous introduction of dislocations and Cluster (2) can significantly suppress the natural aging and promote the precipitation of β″ phase, and reduce the effects of deformation hardening by dynamic recovery.展开更多
This study investigated the effects of superheated steam(SS)treatment at different temperatures(120℃,150℃,180℃)on the physicochemical properties of broken rice flour and the quality of broken rice cakes.SS treatmen...This study investigated the effects of superheated steam(SS)treatment at different temperatures(120℃,150℃,180℃)on the physicochemical properties of broken rice flour and the quality of broken rice cakes.SS treatment at 120℃ significantly enhanced the moisture content of broken rice flour(P<0.05).In contrast,treatments at 150℃ and 180℃ caused decrease of moisture content,amylose leaching,and reduction of damaged starch content.After SS treatment,the pasting properties of broken rice flour increased,along with the rising of storage modulus and loss modulus.The proportion of short chains(DP 6-12)in amylopectin increased from 29.42%to 34.80%(P<0.05),which could delay starch retrogradation.Compared with untreated ones,the SS-150 broken rice cakes showed a significantly higher specific volume(2.96 mL/g,P<0.05),more uniform cell structure,and lower hardness(1.66 N)and chewiness(10.22 mJ).After 7 days of storage,cakes from SS-treated rice flour(150℃ and 180℃)had significantly reduced hardness and chewiness.The study demonstrated that SS treatment could improve the properties of broken rice flour and enhance the quality of broken rice cakes,especially at 150℃ and 180℃.This study presents a method for improving the quality of broken rice flour and rice cakes using superheated steam treatment,addressing challenges related to poor flour characteristics and suboptimal cake quality.The findings offer technical and theoretical support for enhancing rice cake production,contributing to the comprehensive utilization of rice resources.展开更多
基金Supported by Heilongjiang Provincial Fruit Tree Modernization Agro-industrial Technology Collaborative Innovation and Promotion System Project(2019-13)。
文摘In order to obtain better quality cookies, food 3D printing technology was employed to prepare cookies. The texture, color, deformation, moisture content, and temperature of the cookie as evaluation indicators, the influences of baking process parameters, such as baking time, surface heating temperature and bottom heating temperature, on the quality of the cookie were studied to optimize the baking process parameters. The results showed that the baking process parameters had obvious effects on the texture, color, deformation, moisture content, and temperature of the cookie. All of the roasting surface heating temperature, bottom heating temperature and baking time had positive influences on the hardness, crunchiness, crispiness, and the total color difference(ΔE) of the cookie. When the heating temperatures of the surfac and bottom increased, the diameter and thickness deformation rate of the cookie increased. However,with the extension of baking time, the diameter and thickness deformation rate of the cookie first increased and then decreased. With the surface heating temperature of 180 ℃, the bottom heating temperature of 150 ℃, and baking time of 15 min, the cookie was crisp and moderate with moderate deformation and uniform color. There was no burnt phenomenon with the desired quality. Research results provided a theoretical basis for cookie manufactory based on food 3D printing technology.
文摘This paper investigated an experimental method for bake hardening properties, a technique for deriving the true stress-strain curves after reaching the maximum load, and a constitutive equation considering both work hardening and bake hardening in order to apply the work hardening occurring in the forming process of parts and the bake hardening induced in the baking process to an automotive crash simulation. A general bake hardening test is that a pre-tensioned specimen is baked and then the same specimen is tensioned again without any further treatment. For a bake hardening test of automotive steel with a tensile strength of 1.2 GPa or more, fractures often occur in curvature section outside, an extensometer due to the difference in the material strength caused by non-uniform bake hardening. This causes a problem in that the bake hardening properties cannot be obtained. In this paper, to prevent curvature fracture, tensile specimens were re-machined in the uniformly deformed region of large specimens subjected to pre-strain, and the re-machined specimens with uniform strength in all regions were re-tensioned. In the bake hardening test of ultra-high strength steels with a tensile strength of 1 GPa or more, shear band fractures occur when the pre-strain is large. This makes it impossible to obtain a true stress-strain curve because there is no uniformly deformed region under a tensile test. To overcome this problem, a new method to calculate the true stress-strain curve by comparing experimental results and the load calculated by the local strain obtained from digital images was developed. This method can be applied not only where shear band deformation occurs, but also in necking deformation, and true stress-strain curves for strains up to 2 - 3 times the uniform elongation can be obtained. A new constitutive equation was developed since an appropriate hardening model is required to simultaneously apply the work hardening and the bake hardening to the simulation. For the newly developed model, the user material subroutine of LS-Dyna was configured, and the simulation was performed on the single hat specimens with pre-strain. When both work hardening and bake hardening were considered, there was a significant increase in absorbed energy compared to when only work hardening was considered. This means that both work hardening and bake hardening should be considered in the car crash simulations to enhance the accuracy of the simulation.
基金This work was financially supported by the Joint Funds of the National Natural Science Foundation of China(Grant No.U1808216)the Shanxi Provincial Key Research and Development Project(2022ZDYF072).
文摘A cold method was used to prepare coated sand for application in the selective laser sintering(SLS)process.Tensile strength,loss on ignition,gas evolution,and accuracy of the SLS samples were tested and analyzed,and the baking process was thoroughly investigated.Compared with coated sand prepared by the hot method,the cold method yields a more uniform and complete resin film on the sand's surface,resulting in enhanced tensile strength and accuracy.Additionally,the cold method requires a lower binder content to meet the same strength requirements,thereby minimizing gas evolution,reducing porosity defects,and ultimately improving casting quality.The coated sand samples prepared through the cold method exhibit superior accuracy,with a size error of within±0.4 mm.In contrast,the coated sand samples prepared by the hot method display a lower accuracy,with an average negative error of 2.1993 mm.The highest tensile strength could be attained by controlling the baking temperature within a suitable range(180-190°C),which can effectively reduce the generation of gas,thus contributing to improved overall performance.
文摘The study investigates the effects of pre-strain on the bake hardenability and precipitation behavior of Al-Mg-Si automotive body sheets. The scanning electron microscopy, transmission electron microscopy, tensile test, Vickers hardness test, and differential scanning calorimetry were conducted for the purpose. It was found that the pre-strain treatment partially inhibits the natural aging hardening effect but cannot completely eliminate it. The pre-straining significantly enhances the bake hardening effect, with the 5% pre-strain sample showing the highest increase in yield strength and hardness. The formation of fine β" precipitates and dislocation structures contribute to the observed strengthening. Additionally, the study highlights the importance of optimizing pre-strain levels to achieve the best balance between strength and ductility in bake-hardened aluminum alloys.
基金Project(51105139)supported by the National Natural Science Foundation of ChinaProject(2010CB731706)supported by the National Basic Research Program of China
文摘The effects of copper on the ageing precipitation behavior of as-quenched and pre-aged AA6016 aluminum alloy were studied by differential scanning calorimetry (DSC), Vickers hardness measurement and transmission electronic microscopy (TEM). The results indicate that the addition of copper facilitates the growth of clusters (GP I) to the critical size during pre-ageing. Therefore, the addition of copper accelerates the transition from GP I (pre-β") to GP II (β") during final artificial ageing, and finally results in the favorable paint-bake response. However, the one with the copper level of 0.3% does not show significant baking hardening response as expected. Pre-aging can also reduce the detrimental effect due to natural aging of copper-containing alloys.
基金financially supported by the National Key Project of Scientific and Technical Supporting Programs of China (No. 2011BAE13B07)
文摘In a typical process, C-Mn steel was annealed at 800℃ for 180 s, and then cooled rapidly to obtain the ferrite-martensite microstructure. After pre-straining, the specimens were baked and the corresponding bake-hardening (BH) values were determined as a function of pre-strain, baking temperature, and baking time. The influences ofpre-strain, baking temperature and baking time on the microstructure evolution and bake-hardening behavior of the dual-phase steel were investigated systematically. It was found that the BH value apparently increased with an increase in pre-strain in the range from 0 to 1%; however, increasing pre-strain from 1% to 8% led to a decrease in the BH value. Furthermore, an increase in baking temperature favored a gradual improvement in the BH value because of the formation of Cottrell atmosphere and the precipitation of carbides in both the ferrite and martensite phases. The BH value reached a maximum of 110 MPa at a baking temperature of 300℃. Moreover, the BH value enhanced significantly with increasing baking time from 10 to 100 min.
基金Project (2005CB623703) supported by the Major State Basic Research and Development Program of ChinaProject (2008AA030502) supported by the National High-Tech Research and Development Program of China
文摘Pitch and TiB2/C green composite cathode material were respectively analyzed with simultaneous DSC-TGA, and effects of three baking processes of TiB2/C composite cathode material, i.e. K25, K5 and M5, on properties of TiB2/C composite cathode material were investigated. The results show that thermogravimetrie behavior of pitch and TiB2/C green composite cathode is similar, and appears the largest mass loss rate in the temperature range from 200 to 600 ℃. The bulk density variation of sample K5 before and after baking is the largest (11.9%), that of sample K25 is the second, and that of sample M5 is the smallest (6.7%). The crushing strength of sample M5 is the biggest (51.2 MPa), that of sample K2.5 is the next, and that of sample K5 is the smallest (32.8 MPa). But, the orders of the electrical resistivity and electrolysis expansion of samples are just opposite with the order of crushing strength. The heating rate has a great impact on the microstructure of sample. The faster the heating rate is, the bigger the pore size and porosity of sample are. Compared with the heating rate between 200 and 600℃ of samples K25 and K5, that of sample M5 is slower and suitable for baking process of TiB2/C composite cathode material.
文摘In an anode baking horizontal flue ring furnace, the temperature distribution is one of the key factors influencing the quality of baked anode and is closely correlated with the gas flow. To understand the gas flow distribution in the flue, Navier Stokes equation with " k ε " two equation turbulence model was adopted and the simulation on the gas flow was performed. The numerical simulation results showed that the even direction of gas flow should be considered in the design of flue baffles and the gas flow distribution was really uneven in the flue in practical use. By adjusting the number and location of flue baffles rationally, the even distribution of gas flow can be improved obviously.
文摘Among the folate compounds, 5-methyltetrahydrofolic acid (5-CH3THF) is regarded as one of the most bioactive forms of folate. It is regarded as the better source of folate to humans as compared to folic acid, a synthetic form of folate, which is used for fortifying foods to prevent the incidence of neural tube defects in the new born babies. The use of 5-CH3THF as an alternative fortificant, in place of folic acid, has been explored by various researchers. However, fortification of 5-CH3THF is problematic due to its lower stability. This study investigated the stability of microencapsulated 5-CH3THF in biscuits baked at various temperatures and times as well as changes in their physical properties. Microcapsule with pectin and alginate ratio of 80:20, prepared by spray drying, gave the highest retention (68.6%) of the 5-CH3THF, therefore, chosen for fortification. The encapsulated and unencapsulated 5-CH3THF were mixed separately with flour and biscuit ingredients and baked at 180℃, 200 and 220℃, each for 5, 9 and 12 min. The inclusion of encapsulated and unencapsulated 5-CH3THF in the biscuit formulation and subsequent baking at various temperatures and times resulted in retention of 5-CH3THF from 19.1% to 1.7%. Microencapsulation of 5-CH3THF slightly improved the retention of 5-CH3THF over unencapsuated biscuits at 180℃ for 5 min, but almost no such effect was achieved under baking temperatures of 200℃ and 220℃. Physical analysis showed darker colour, harder texture and lower moisture content for biscuits baked at higher test temperatures. It seems intense heating condition that caused “over baking” of the biscuit likely to be responsible for the loss of the vitamin as well as less desirable physical properties of the biscuits.
文摘The purpose of this study was to investigate the suitability of palm diacylglycerol (PDAG)-enriched formulations for bakery shortening. Three types of palm diacylglycerol olein (PDAGOL) at different degree of unsaturation (PDAGOL1V56, PDAGOLIV62 and PDAGOLIV64) were used as main raw materials blended with palm stearin (PS). The blending compositions ranged from 30% to 70% of PDAGOLIV56/PS, PDAGOLIV62/PS and PDAGOLIV64/PS, respectively. The physicochemical properties of all binary blend systems were characterized for fatty acid composition (FAC), slip melting point (SMP) and solid fat content (SFC). The selected bakery shortening formulations were further characterised for polymorphic form of fat crystal and thermal behavior, using X-ray diffractometer (XRD) and differential scanning calorimetry (DSC). Bakery shortening enriched with diacylglycerol that were produced from 40DS56 (40% PDAGOLIV56/60% PS), 40DS62 (40% PDAGOL1V62/60% PS) and 40DS64 (40% PDAGOLIV64/60% PS) had 45%-50% unsaturated fatty acid and crystallized in β + β polymorphs; thus they were suitable for shortening system. Based on product's baking performance, it could be found that all Madeira cakes prepared from bakery shortening enriched with diacylglycerol had higher specific cake volume as compared to commercial shortening (CS). In customer acceptance test, Madeira cake made from 40DS56 shortening scored the highest rating for all sensory attributes, including overall customer acceptability. It had given an indication that 40DS56 shortening formulation was the most suitable fat blends to be used as bakery shortening.
文摘The accumulation of protein fractions was analyzed on developing and mature wheat grains of three cultivars differing in protein content and baking quality. There was a slight difference in the accumulation of cytoplasmic proteins in the cultivars used. The high yield but low protein cultivar showed a consistent decline of protein content during grain filling but the high - protein cultivars increased their psotein contant after 25 days post-anthcsis. The accumulation of storage proteins was different from that of cytoplasmic protein, and there were also cultivar variations. However, all cultivars reached their, maximum-synthesizing capacity for storage proteins at maturity. The relationship between the protein fractions or their ratio and baking quality was also discussed.
文摘Two experimental steels with tensile strength above 980 MPa were prepared to investigate the effect of prestrain and baking on their mechanical and fracture behaviors. The experimental results reveal that,for both experimental steels,with increases in the prestrain level,the bake hardening value increases before reaching a maximum point,and then decreases with further increases in the prestrain level. The results of a "bending-baking-secondary bending"test indicate that the secondary bendability deteriorates at a high level of prestrain. The yield strength of the experimental steels was found to increase and the elongation to decrease after high levels of prestrain and bake hardening. Fracture morphology images indicate that a high prestrain level is associated with shallow dimples and more and larger local cleavage areas.
文摘An existing small-scale single-powered baking oven was modified and optimize into a dual-powered oven. The oven was redesigned to accommodate the initially designed firewood heat source and the newly introduced gas heat source. Four heat exchangers (thermal pipes) were introduced to the baking chamber for effective heat and mass transfer during baking of bread dough. The thermal pipes were made of 2 mm thick hollow galvanized steel pipe of 23 mm diameter and 660 mm length. The performance of the oven was evaluated using the standard performance index, which includes baking capacity, baking efficiency and weight loss of the baked bread. The baked bread’s physical properties were determined and analyzed using Duncan multiple range ANOVA test at significant level of <em>p</em> < 0.05. These properties were optimized to determine the generate regression models using 3D model plot. The baking capacity, baking efficiency, weight loss and optimum baking temperature were: 101.9 kg/h, 46.44% (wood-fired);70.34% (gas-fired), 13.5 g (wood-fired);and 25.5 g (gas-fired), 150<span style="white-space:nowrap;">˚</span>C, respectively. The physical properties of baked bread, wood-fired were found to correspond with that of gas-fired oven. The modified oven can be used for the baking of dough at domestic, small and medium scale bakery.
文摘The baking industry is a part of the food industry. Since the beginning of the 1980s, China has carried out a strategy of developing instant foods. The baking industry has developed rapidly, and has introduced big changes in the structure of its varieties, quality of products, decoration of packages and technical equipment. So far, there are 4, 000 enterprises baking foods in China with 360, 000 staff and workers and an annual capacity of baked foods of two
文摘In this paper, a 2D transient finite element analysis was carried out for a new type of solar powered injera baking system. In the proposed system (currently under development), heat transfer oil is heated using solar energy by parabolic trough and the oil circulates through the space below the baking pan in the kitchen. Based on previous finite element study on existing electric injera baking pans, a new type of baking pan made from ceramic with 8 mm thickness was manufactured and used for the proposed system. The model was further extended to study the heat up time and temperature distributions during initial heat up and cyclic baking of the new model. The proposed baking pan that uses solar energy gives acceptable heat up and baking time compared to existing conventional baking methods. Generally, the finite element model predicts well the temperature distributions during initial heat up and cyclic baking.
文摘Gluten,the protein responsible for the superior viscoelastic properties of refined wheat flour dough over glutenfree cereals,causes celiac disease in people susceptible to gluten-allergy.Moreover,the sustainability of using wheat flour in baked foods is threatened by its high cost,especially in countries that depend on imported wheat for their bakery industry.Research has shown that hydrocolloids serve as gluten replacements in baked foods,in response to these challenges.Food hydrocolloids are a class of high-molecular weight polysaccharides and proteins,which serve as functional ingredients in the food industry that modify the foods’rheological and textural properties.They function as stabilizers,viscosity modifiers,gelling agents,water binders,fibres,and inhibitors of ice crystal in foods.Further,food hydrocolloids have also been reported to possess health-promoting properties,such as lowering of postprandial blood glucose and plasma cholesterol concentrations,colon cancer prevention,and modulation of intestinal transit and satiety.They are obtained from plants,animals or microorganisms,and can be used in their natural or modified forms.The aim of this paper is to review the functional benefits of natural and modified hydrocolloids as gluten replacements in baked foods,emphasizing their physicochemical,nutraceutical,and sensorial importance.The application effects of food hydrocolloids as gluten substitutes in gluten-free baked products’quality were discussed.Also,some practical approaches to improve the quality of gluten-free baked products,in response to an increasing consumers’demand and the rising cost of refined wheat flour were highlighted.
文摘Sodium bicarbonate is sometimes used to aid in the extraction of total polyphenols. Its main effect is to increase the pH of the extraction solution. Raising the pH can cause changes in the chemical structure of polyphenols. This can lead to variations in their biological properties, solubility and stability. This work studied the effect of sodium carbonate on the extraction by aqueous decoction of total polyphenols from the leaves of Combretum micranthum. The content of total phenolic compounds in the extracts was estimated by the Folin-Ciocalteu method. The color of the samples was measured using a colorimeter (type: KONICA MINOLTA. Japan) based on the CIELAB color system. The results obtained were subjected to a one-way ANOVA analysis of variance with R software version 3.2.4 Revised (2018) and Minitab-18 software. The results reveal a drop in the concentration of extracted polyphenols proportional to the addition of sodium carbonate, i.e. a drop from 3.30 to 1.04 mg·AG·100 g<sup>-1</sup> of extract on whole leaves and 3.921 to 2.551 mg·AG·100 g<sup>-1</sup> extract on crushed leaves. On the other hand, the intensity of the coloring of the extracts increases significantly with the addition of sodium carbonate from 0.0 g·L <sup>-1</sup> to 0.666 g·L<sup>-1</sup>.
基金Project(2014DFA51270)supported by the International Science and Technology Cooperation Program of ChinaProject(51421001)supported by the Foundation for Innovative Research Groups of the National Natural Science Foundation of China
文摘The influences of high temperature pre-straining (HT-PS) on the natural aging and bake hardening of Al?Mg?Si alloys were investigated by Vickers microhardness measurements, differential scanning calorimetry (DSC) analysis and transmission electron microscopy (TEM) characterization. The results show that pre-straining at 170 °C immediately after quenching can effectively resolve the rather high T4 temper hardness caused by the conventional room temperature (RT) pre-straining treatment, and give a better bake hardening response (BHR) after paint-bake cycle. HT-PS 7% at 170 °C for 10 min is chosen as the optimum process as it provides lower T4 temper hardness and better BHR. The simultaneous introduction of dislocations and Cluster (2) can significantly suppress the natural aging and promote the precipitation of β″ phase, and reduce the effects of deformation hardening by dynamic recovery.
基金supported by the Postdoctoral Innovation Project of Shandong Province (SDCX-ZG-202303090).
文摘This study investigated the effects of superheated steam(SS)treatment at different temperatures(120℃,150℃,180℃)on the physicochemical properties of broken rice flour and the quality of broken rice cakes.SS treatment at 120℃ significantly enhanced the moisture content of broken rice flour(P<0.05).In contrast,treatments at 150℃ and 180℃ caused decrease of moisture content,amylose leaching,and reduction of damaged starch content.After SS treatment,the pasting properties of broken rice flour increased,along with the rising of storage modulus and loss modulus.The proportion of short chains(DP 6-12)in amylopectin increased from 29.42%to 34.80%(P<0.05),which could delay starch retrogradation.Compared with untreated ones,the SS-150 broken rice cakes showed a significantly higher specific volume(2.96 mL/g,P<0.05),more uniform cell structure,and lower hardness(1.66 N)and chewiness(10.22 mJ).After 7 days of storage,cakes from SS-treated rice flour(150℃ and 180℃)had significantly reduced hardness and chewiness.The study demonstrated that SS treatment could improve the properties of broken rice flour and enhance the quality of broken rice cakes,especially at 150℃ and 180℃.This study presents a method for improving the quality of broken rice flour and rice cakes using superheated steam treatment,addressing challenges related to poor flour characteristics and suboptimal cake quality.The findings offer technical and theoretical support for enhancing rice cake production,contributing to the comprehensive utilization of rice resources.