Effects of Pre-Strain on Bake Hardenability and Precipitation Behavior of Al-Mg-Si Automotive Body Sheets

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.

Natural and modified food hydrocolloids as gluten replacement in baked foods:Functional benefits

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.

Effects of high temperature pre-straining on natural aging and bake hardening response of Al-Mg-Si alloys

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.

Experimental study on Ti+Nb bearing ultra-low carbon bake hardening sheet steel hot-rolled in the ferrite region

A Ti＋Nb bearing ultra-low carbon bake hardening sheet steel hot-rolled in the conventional austenite region and in the ferrite region with lubrication was experimentally studied. Subsequent cold rolling and continuous annealing processes were also conducted. The results show that microstructures of ultra-low carbon bake hardening hot strips at room temperature are basically irregular polygonal ferrites. The yield strength, ultimate tensile strength, n value, and r value of the No.2 specimen hot-rolled in the ferrite region with lubrication are 243 MPa, 364 MPa, 0.29, and 1.74, respectively, which are similar to those of the No.1 specimen hot-roiled in the conventional austenite region. The elongation rate and bake hardening value of No.2 specimen are 51% and 49.4 MPa, respectively, which are greater than those of No. 1 specimen. The No.2 specimen hot-rolled in the ferrite region with lubrication exhibits good mechanical properties and relatively excellent baking hardening performance. Therefore, the hot rolling experiment of Ti＋Nb bearing ultra-low carbon bake hardening steel in the ferrite region with lubrication is feasible and can be considered in the future industrial trial production.

Experimental Study of Flexural Behaviour of Reinforced Baked Clay Beams under Impact Loading

This paper presents behaviour of Reinforced Baked Clay (RBC) beams under drop weight impact loading. The beams were made of two different grades of baked clay with cube crushing strength of 20 MPa and 30 MPa, respectively. The RBC beams were subjected to repeated drop weight loading by a hammer of weight equal to that of the specimen being tested. The results showed that the impact resistance of the RBC beams was governed by the compressive strength of the baked clay. Failure of grade 20 beams occurred due to irregular cracks and the beams of grade 30 failed by opening of a single crack at mid span. It was observed that the beams of grade 30 had sustained about 1.5 times more number of impacts until steel in tension zone yielded and failed completely after necking.

Effect of Reinforcement on Deflection and Cracks in Baked Clay Beams

For low cost houses in Pakistan, Reinforced Baked Clay (RBC) is considered to be a potential construction material as a substitute of Reinforced Cement Concrete (RCC). Deflection and cracks are important parameters for design of beams in a building. However, for RBC beams it is still unknown that how the deflection and crack width could be controlled by increasing ratio of reinforcement. This study investigates the effect of ratio of reinforcement on deflection and cracking behaviour of baked clay beams. The results show that by increasing area of reinforcement by 50% in baked clay beams: 1) deflection was decreased to 2.5 times, and 2) crack width was reduced to three times.

Structural Properties of Baked Clay Bricks Fired with Alternate Fuels

Coal is used as a traditional fuel for firing of clay bricks in kilns. The cost of coal is high and is increasing continuously. This paper describes the effect of alternate fuels on compressive strength, water absorption and density of fired clay bricks. The alternate fuels used in this study were 1) rapeseed husk (Type I), 2) combination of sugarcane-bagasse, rice husk and used clothes (Type II) and 3) coal (Type III). The results show that compressive strength of bricks fired using Type I and Type II fuels was decreased to 11% and 7%, respectively, compared to those fired with coal. However, the values of water absorption and density of bricks fired with Type I and Type II fuels were almost same as exhibited by those baked with coal. This study shows that a saving of 25%, and 18% could be achieved when the bricks were fired using Type I and Type II fuels, respectively, compared to those fired with coal.

Comparison of Compressive and Tensile Strength of Baked Clay with Those of Normal Concrete

Due to high cost of aggregates, cement and steel in plain regions of Pakistan, low income people are unable to get their houses constructed using Reinforced Cement Concrete (RCC). In this study, potential of baked clay as an economical material of building construction is investigated in order to replace normal concrete. For this purpose, compressive strength and tensile strength of baked clay fired at 1000℃ were determined. The results show that the compressive strength and tensile strength of baked clay are about 65%, and 80% more than those of corresponding values of normal concrete, respectively. This implies that by utilizing reinforced baked clay instead of RCC, saving of cement aggregates and reinforcing steel could be achieved.

Effect of Reinforcement on Deflection and Cracks in Baked Clay Beams Subjected to Impact Loading

Attempts are being made to utilize Reinforced Baked Clay (RBC) as a substitute of Reinforced Cement Concrete (RCC) for construction of low cost houses in plains of Pakistan. Since baked clay is considered to be more brittle as compared to concrete. Therefore, it is necessary to investigate how deflection and crack width of RBC beams subjected to impact loading are governed by amount of reinforcement. This paper presents the behaviour of RBC beams under drop weight impact loading. The beams were reinforced with two steel bars, one in compression zone and the other in tension zone. In group A beams, the diameter of steel bars was 12.7 mm, while the beams of group B were reinforced with steel bars of 15.8 mm diameter. The RBC beams were subjected to repeated impacts of a hammer of mass 21 kg falling from a height of 1000 mm. The results show that 1) three times reduction in deflection, and 2) 2.5 times decrease in crack width, were achieved in RBC beams by increasing the area of steel to 50%. In addition to this, all the RBC beams failed within nine blows of the hammer, irrespective of area of reinforcement.

Relation between Compressive Strength of Baked Clay Cubes and Cylinders

Reinforced Baked Clay (RBC) seems to be potential alternative of Reinforced Cement Concrete (RCC) for construction of low cost houses. In order to utilize RBC as a construction material for buildings, it is necessary to understand compression behaviour of baked clay. In this paper, relation between cube crushing strength and cylinder strength of baked clay is presented. For this purpose, clay beams were cast in a mould and compacted at a pressure of 6 MPa. The clay beams were dried and fired in a kiln at a temperature of 900?C. Cubes of 150 mm size were sawed from a baked clay beam. Cylinders of 150 mm diameter and 300 mm height were cut, from another baked clay beam, using core cutter machine. Both the cubes and cylinders were tested for compressive strength in Universal Testing Machine. The results showed that the cube crushing strength of baked clay was 25 MPa and the ratio of the compressive strength of the cylinders and the cubes was found to be 0.6. Suggestions for improvement of compressive strength of baked clay cylinders are also discussed.

Flexural Behaviour of Reinforced Baked Clay Beams

Construction of Reinforced Cement Concrete (RCC) houses is unaffordable for low income people living in plains of Pakistan because of high cost of cement and aggregates. In such regions, use of Reinforced Baked Clay (RBC) is considered to be a cheaper alternative for RCC. This paper presents structural behaviour of RBC beams. The results of RBC beams were compared with a control RCC beam of same size and reinforcement. Both types of the beams showed similar load deflection behaviour in pre-yield stage. Whereas, in post yield stage, the RBC beams showed comparatively more deflection as compared to the RCC beam. The ultimate load carrying capacity of the RBC beams was almost similar to that of the RCC beam. This study suggests that the RBC beams can be used economically instead of RCC beams without losing strength and safety of a building.

Suitability of Large Sized Compacted Baked Clay Blocks as a Walling Material

Some disadvantages associated with conventional brick masonry are: high cost of construction, lower compressive strength and less durability. In order to resolve these problems, a new technique of constructing walls using large size baked clay blocks is introduced. For this purpose, clay blocks of size 150 mm × 300 mm × 1980 mm were cast at a pressure of 6 MPa, and fired at a temperature of 700℃. In this paper, compressive strength and tensile strength of baked clay were investigated in order to find its suitability as a walling material for low cost houses. Cubes of 150 mm sides were tested in compression and the beams were tested in flexure. The results showed that compressive strength of baked clay cubes was found to be 10 MPa and tensile strength, in terms of modulus of rupture, was found to be 2.3 MPa. Since the baked clay blocks are larger in size than traditional bricks, it is inferred that the blocks could be used as a cheaper and stronger walling material.

智能体验再升级——体验第二代长帝e·Bake互联网烤箱CRDF32A

随着人们对生活品质的要求不断提升,烘焙成为很多人生活的一部分。＂分享美食＂、＂晒成果＂、＂圈内交流＂,烘焙的门槛越来越低,不再只是烘焙达人的专属。2015年,第二代长帝e·Bake互联网烤箱CRDF32A让笔者当了一回烘焙达人,体验到烘焙的魅力。更重要的是,这款产品让笔者这个门外汉对如今盛行的各种智能家电有了信心。笔者曾经体验过第一代长帝e·Bake互联网烤箱。当时,笔者觉得那款产品还说得过去,已有几分智能的＂意思＂。

Effects of pre-strain and baking parameters on the microstructure and bake-hardening behavior of dual-phase steel

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.

Bake hardening behavior of TRIP and DP steels

The bake hardening （BH） behavior of transformation-induced plasticity （TRIP） and dual-phase （DP） steels after different prestrains was studied. The experimental results indicate that TRIP steel exhibits good BH ability while DP steel does not, and prestrain displays a strong effect on the BH values of both steels. The comparison of microstructures of the two steels showed that the hard second phase in the matrix might be harmful to the BH ability. For deformed specimens, baking resulted in a loss of uniform elongation, but there was no obvious decrease in uniform elongation for unprestrained specimens.

Microstructural characteristics and paint-bake response of Al-Mg-Si-Cu alloy

The microstructural characteristics and paint-bake response of 6022 alloy with 0.3% Cu(mass fraction)were studied using optical microscope,scanning electron microscope(SEM),transmission electron microscope(TEM)and tensile tester.The results indicate that the phase constituents in the as-cast microstructure are Mg2Si,Si,Al5Cu2Mg8Si6,Al5FeSi,α-Al(MnCrFe)Si and CuAl2.During the following homogenization,CuAl2,Al5Cu2Mg8Si6 and Mg2Si phases are almost completely dissolved,and Al5FeSi transforms to α-Al(MnCrFe)Si particles.After rolling,the phase constituents in the alloy change less except the precipitation of Mg2Si particles,and the precipitation behavior of Mg2Si strongly depends on the thermomechanical conditions.Cu addition significantly increases the paint-bake response of 6022 alloy by facilitating the formation of β-" phase.Therefore,the tensile strength of 6022 alloy with 0.3% Cu is higher than that of 6022 alloy without Cu after paint-bake cycle.

Processing Technique of Carbonizing by Stir-Frying for Baked Rheum tanguticum Maxim.ex Balf. Optimized by Orthogonal Design

[Objectives]To optimize the processing technology of baked Rheum tanguticum carbon.[Methods]Firstly,the baking temperature and baking time were investigated by single factor,and the content of 5-hydroxymethylfurfural(5-HMF)was determined by HPLC.The main influencing factors of baking effect were baking temperature,baking time and tablet specifications.The L 9(34)orthogonal design experiment was carried out to optimize the processing technique of R.tanguticum carbon.[Results]The optimum processing technique was as follows:small-sized tablets,controlled oven baking temperature at(210±2)℃,and baking time of 20 min.[Conclusions]The optimum processing technique of R.tanguticum carbon is reasonable and feasible.Thus,this experiment can provide a certain reference for processing method and quality control of R.tanguticum carbon.

Physicochemical Properties, Baking Performance and Sensory Evaluation of Bakery Shortening Enriched with Diacylglycerol

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.

Sulphuric Acid Bake-Leach Process for the Treatment of Mixed Copper-Cobalt Oxide Ores

A sulphuric acid bake–leach method for the treatment of mixed copper-cobalt oxide minerals was investigated as an alternative to the reductive leaching method. Sulphuric acid bake-leach process of the mixed copper-cobalt oxide ore was carried out by mixing the sample with sulphuric acid followed by baking of the mixture in a muffle furnace. Baking tests were conducted at different conditions such as temperature, time, and varying amounts of acid. The reacted samples were then subjected to water leaching at room temperature to determine the leachability of copper and cobalt from the baked material. The dissolutions of copper and cobalt were dependent on acid concentration with cobalt showing more sensitivity to the amount of acid. Both copper and cobalt were extracted from the baked material within short leaching times and without the addition of reducing agents. The outcome of this work has shown that the sulphuric acid bake-leach process is a possible alternative to the reductive leaching method for copper-cobalt oxide ores.

不同环境下酸性闪长岩沥青混合料长期水稳性能评价研究

通过浸水马歇尔试验、冻融劈裂试验以及车辙试验评价了采用酸碱复合集料、单掺水泥(2%水泥替代矿粉)、消石灰(30%消石灰水浸泡石料)以及抗剥落剂(0.3%抗剥落剂改性沥青)的酸性闪长岩沥青混合料的短期水稳性能,再通过反复冻融劈裂试验、反复冻融烘劈裂试验以及反复酸蚀冻融劈裂试验测试处置酸性闪长岩沥青混合料在不同环境下的长期水稳性能。结果表明:酸性闪长岩的物理力学性能均满足规范要求;处置后酸性闪长岩沥青混合料的短期水稳性能显著提升,满足规范使用要求;但经0.2%抗剥落剂处置的酸性闪长岩沥青混合料在高温下的长期水稳性能较差;经30%消石灰水处置的酸性闪长岩沥青混合料具有良好的长期水稳性能,可推荐应用于工程中。