Estimate the required length of thread engagement that will ensure tensile failure of the cap screw before the threads are stripped in the aluminum block.

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1.A -20 UNF-2A SAE Grade 2 steel cap screw is being considered for use in attaching a cylinder head to an engine block made of 356.0 cast aluminum . It is being proposed to engage the cap screw into an internally threaded hole tapped directly into the aluminum block. Estimate the required length of thread engagement that will ensure tensile failure of the cap screw before the threads are stripped in the aluminum block. Assume that all engaged threads participate equally in carrying the load. Base your estimate on direct shear of the aluminum threads at the major thread diameter, and use the distortion energy theory of failure to estimate the shear yield strength for the aluminum block.

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Calculate the torque required to accomplish this.

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1.A standard coarse-thread metric cap screw made of steel has a major diameter of 10.0 mm. If a torque wrench is used to tighten the cap screw to a torque of 35 N-m, estimate the axial preload force induced in the cap screw. It may be assumed that the coefficient of friction is about 0.15 for both threads and collar.

2. Engineering specifications for a machine tool bracket application call for a nonlubricated M30 2 threaded fastener of property class 8.8 to be tightened to 100 percent of proof load. Calculate the torque required to accomplish this. It may be assumed that the coefficient of friction is about 0.15 for both the threads and the collar.

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you are being asked, as an engineering consultant, whether the available cap screws with head markings of five radial lines can be safely substituted for the broken originals. How do you respond?

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1.A high-speed “closing machine” is used in a tomato canning factory to install lids and seal the cans. It is in the middle of the “pack” season and a special bracket has separated from the main frame of the closing machine because the -24 UNF-2A hex-head cap screws used to hold the bracket in place have failed. The head markings on the failed cap screws consist of the letters BC in the center of the head. No cap screws with this head marking can be found in the storeroom. The -24 UNF-2A cap screws that can be found in the “high-strength” bin have five equally spaced radial lines on the heads. Because it is so important to get up-and-running immediately to avoid spoilage, you are being asked, as an engineering consultant, whether the available cap screws with head markings of five radial lines can be safely substituted for the broken originals. How do you respond? Justify your recommendation.

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Examine a number of large flood gates installed in 1931 for irrigation control at a remote site on the Indus River in Pakistan.

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1.You have been assigned the task of examining a number of large flood gates installed in 1931 for irrigation control at a remote site on the Indus River in Pakistan. Several large steel bolts appear to have developed cracks, and you have decided that they should be replaced to avert a potentially serious failure of one or more of the flood gates. Your Pakistani assistant has examined flood gate specifications, and has found that the original bolts may be well characterized as 32-mm mediumcarbon quenched and tempered steel bolts, of property class 8.8. You have brought with you only a limited number of replacement bolts in this size range, some of which are SAE Grade 7, and others that are ASTM Class A325, type 3. Which, if either, of these replacement bolts would you recommend as a substitute for the cracked originals? Justify your recommendation.

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idea of a critical period to learning language

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Chapter 9 on language development introduced the idea of a critical period to learning language. Erik Lenneberg proposed a hypothesis called the Critical Period Hypothesis that states there is a biologically-determined period of time during which language acquisition must occur. Attempts to learn language after puberty (around age 12), according to this hypothesis, will be more difficult and ultimately unsuccessful. Those who argue in favor of a critical period for learning language often use children who have been deprived of language input and their inability to successfully learn language as the primary evidence (e.g,
genie Those who argue against the critical period for learning language often use evidence from brain development and neuroimaging studies, as well as studies of second language learning. Do you think Lenneberg’s critical period hypothesis is supported by research? In your response, briefly tell me what it means to be successful in learning language (i.e., what should the outcome look like with respect to the 5 basic aspects of language) and then provide at least three (3) reasons why you believe the critical period hypothesis is or is not supported by research. Your answer should appropriately use/cite research. You must use a minimum of 3 references for this prompt. These references may only be peer-reviewed journal articles, chapter, or books. You may not use either web sites or your textbook as a source and cite the 3 references used.