The contribution of small punch testing towards the development of materials for aero-engine applications

This paper, invited for presentation at the 33rd Meeting of the Spanish Group on Fracture and Structural Integrity, March 2016 in San Sebastian, Spain, reviews the recent work carried out in the authors’ laboratory, addressing the elucidation of tensile and creep characteristics of materials for aero engine components. Two specific applications of the Small Punch (SP) test assessment technology were identified, the first of these takes on board the unique potential of the SP test for testing small quantities of materials which are either in development or through their directional structure cannot easily be produced in quantities which would allow conventional mechanical testing. This goal also required the development and procurement of new SP test facilities capable of operation up to 1150 °C. The examples given in this paper are TiAl intermetallic alloys and nickel based single crystals, all studied utilising the Code of Practice for SP Creep Testing. The second application illustrates the use of SP testing to assess both the tensile and creep properties of additive layer manufactured (ALM) alloys such as IN718 and Ti-6Al-4V using the Code of Practice for SP Tensile and Fracture Testing. Due to the unavailability of sufficient material to facilitate conventional testing for comparison of materials property data, SP testing is unable to provide absolute data for all of these applications, nevertheless the ranking capabilities of SP testing are demonstrably proven

Prehistoric human biological adaptation

p. 157-270 : ill., maps ; 26 cm.Includes bibliographical references (p. 255-270)."Skeletal remains from the prehistoric coast of Georgia are the basis for this study. The effects of agriculture on the human skeleton are examined and explained in the present paper. The region was chosen because (1) there is a large skeletal series representative of both an early preagricultural adapatation (2200 B.C.-A.D. 1150) and a later mixed agricultural and hunting-gathering adaptation (A.D. 1150-A.D. 1550); (2) the Georgia coast represents continuous in situ cultural development from at least 2200 B.C. to A.D. 1550, implying human biological continuity for at least 3500 years prior to European contact; and (3) the economic regime for the Georgia coast has been documented by a large body of archaeological and ethnohistoric data. A series of skeletal and dental changes are viewed in light of an adaptational model encompassing disease and size of the hard tissues - skeletal and dental - and their respective responses to the behavioral shift from a hunting and gathering lifeway to one that incorporated corn agriculture after A.D. 1150. The model consists of two parts. First, with the introduction of an agriculture-based diet and consequent increase in population size and density, the pathology reflecting a general rise in occurrence of infectious disease due to an expansion in population size and a high dietary carbohydrate base should increase. Second, with the adoption of corn as a major dietary constituent, the softer foodstuffs and more sedentary lifeway associated with that adaptation should result in a respective decrease in functional demand on the masticatory complex in particular and on the body in general. In addition, the element of poor nutrition should come into play in an economy in which plant domesticates, and corn in particular, are the focus of diet. The comparison and analysis of the pathology and metric data support the model. In addition, the detailed examination of these data by sex suggests that the behavioral alterations that occurred consequent to the change in lifeway differentially affected females"--P. 159

Application of the small punch test to determine the fatigue properties of additive manufactured aerospace alloys

Additive layer manufacturing (ALM) processes are becoming increasingly prevalent in the aerospace industry as design engineers look to profit from the numerous advantages that these advanced techniques can offer. However, given the safety critical nature and arduous operating conditions to which these components will be exposed to whilst in service, it is essential that the mechanical properties of such structures are fully understood. Transient microstructures are a typical characteristic of ALM components and resulting from the thermal cycles that occur during the build operation. Those microstructures make any mechanical assessment an involved procedure when assessing the process variables for any given parameter set. A useful mechanical test technique is small-scale testing, in particular, the small punch (SP) test. SP testing is capable of localised sampling of a larger scale component and presents an attractive option to mechanically assess complex parts with representative geometries, that would not be possible using more conventional uniaxial test approaches. This paper will present the recent development of a small-scale testing methodology capable of inducing fatigue damage and a series of novel tests performed on different variants of Ti-6Al-4V

St. Catherines period mortuary complex

p. 272-341 : ill., 1 map ; 26 cm.Includes bibliographical references (p. 340-341)."The results of archaeological excavations of two St. Catherines period burial mounds - Marys Mound and Johns Mound - by field crews from the University of Georgia and the American Museum of Natural History are presented. Analysis of the ceramics recovered from the two mortuary localities suggests that both mounds were constructed during the terminal phase of the St. Catherines period, probably during the late twelfth or early thirteenth century A.D. Study of the human skeletal remains suggests that these people were physically robust and enjoyed good health, both skeletal and dental. Analysis of nonhuman skeletal remains shows that most identified taxa are present on St. Catherines Island today. In addition, the presence of the domestic pig, Sus scrofa, in association with one iterment from Johns Mound, points to historic (Altahama) period use of this locality. Thin-section analysis of whole clams (Mercenaria mercenaria) from both sites indicates that time of harvesting or death for all specimens falls within 'late fall' to 'late spring' (November to May)"--P. 273

Interracial Public-Police Contact: Relationships with Police Officers’ Racial and Work-Related Attitudes and Behavior

In a sample of Flemish police officers (N = 172), we examined whether interracial public-police contact is associated with police officers’ racial and workrelated attitudes and self-reported behavior. Complementing previous studies, it was revealed that interracial contact (both positive and negative) is related to prejudiced behavior toward immigrants via the mediating role of racial attitudes. Moreover, intergroup contact was also shown to be related to police officers’ organizational citizenship behavior toward colleagues and superiors via their perceptions of organizational fairness. In the discussion section we elaborate on the severe impact of negative contact as well as the applied consequences of our findings within police organizations

Refuge-Deptford mortuary complex

179 p. : ill., maps ; 26 cm.AMNH Library's copies lack t.p.Includes bibliographical references (p. 173-179).Mortuary archaeology on the Georgia coast / David Hurst Thomas and Clark Spencer Larsen -- Archaeological techniques and procedures / David Hurst Thomas and Clark Spencer Larsen -- The Cunningham Mound group / David Hurst Thomas, Clark Spencer Larsen, and Ann Marie Lunsford -- Seaside Mound group / David Hurst Thomas, Clark Spencer Larsen, and Ann Marie Lunsford -- Ceramics / Chester B. DePratter -- Comparisons / David Hurst Thomas -- Implications and some speculations / David Hurst Thomas -- Appendix. Seasonal growth variations in the shells of recent and prehistoric specimens of Mercenaria mercenaria from St. Catherines Island, Georgia / George R. Clark II."Data and implications from nine burial mounds excavated by crews of the American Museum of Natural History on St. Catherines Island, Georgia, are given in this monograph. As a group, these nine sites define a surprisingly homogeneous pattern and these data comprise virtually all that is known regarding the mortuary customs practiced along the Georgia and Florida coast between ca. 1500 B.C. to A.D. 600. The sites are rather unspectacular sand mounds, which exhibit a remarkably consistent stratigraphic patterning. The skeletal materials recovered are poorly preserved, except in the rare case when shell was added to the interment. The radiocarbon evidence, consisting of 29 determinations from the nine mounds, strongly suggests a marked periodicity in the use of these sites. In all cases, the areas seem to have been visited for centuries - in some cases millenia - prior to the actual construction of the mortuary mound. Several graves were placed into this pre-mound surface, and mound-building activities occurred at all sites sometime during the first 600 years A.D. A number of intrusive burials were added shortly thereafter, and then ceremonial activities virtually ceased at all sites. Most cultural materials found inside the mounds were accidental inclusions which resulted from pre-mound sacred (and probably secular) activities. Very few deliberate grave offerings were found. The biocultural evidence suggests that the Refuge-Deptford population enjoyed good health, although they suffered from an extreme rate of dental attrition. Although the data are limited, these sites seem to reflect an egalitarian sociopolitical organization operative during Refuge-Deptford times. The relatively high proportion of bundle burials seems to suggest that the annual round of these peoples exploited both island and mainland resources. We offer a number of cautious speculations regarding the nature of ritual and symbolism during the Refuge and Deptford phases. These suggestions are a variety of hypotheses that require testing with data from both mortuary and habitation sites of this period"--P. 5

A Maternal–Offspring Coadaptation Theory for the Evolution of Genomic Imprinting

Imprinted genes are expressed either from the maternally or paternally inherited copy only, and they play a key role in regulating complex biological processes, including offspring development and mother–offspring interactions. There are several competing theories attempting to explain the evolutionary origin of this monoallelic pattern of gene expression, but a prevailing view has emerged that holds that genomic imprinting is a consequence of conflict between maternal and paternal gene copies over maternal investment. However, many imprinting patterns and the apparent overabundance of maternally expressed genes remain unexplained and may be incompatible with current theory. Here we demonstrate that sole expression of maternal gene copies is favored by natural selection because it increases the adaptive integration of offspring and maternal genomes, leading to higher offspring fitness. This novel coadaptation theory for the evolution of genomic imprinting is consistent with results of recent studies on epigenetic effects, and it provides a testable hypothesis for the origin of previously unexplained major imprinting patterns across different taxa. In conjunction with existing hypotheses, our results suggest that imprinting may have evolved due to different selective pressures at different loci

Natural and cultural history

p. 157-248 : ill., maps ; 26 cm.Includes bibliographical references (p. 244-248).The natural history of St. Catherines Island / David Hurst Thomas -- The prehistory of St. Catherines Island / Clark Spencer Larsen and David Hurst Thomas -- The ethnohistory of the Guale Coast through 1684 / Grant D. Jones -- The history of St. Catherines Island after 1684 / Roger S. Durham and David Hurst Thomas -- Appendix: Notes on ethnohistorical resources and methodology / Grant D. Jones."This volume, the first in a series, considers the natural and cultural background to anthropological research being conducted on St. Catherines Island, Georgia. The island is one of a complex series of barrier islands, of various orgins. The extant vegetation is an interesting mixture of natural succession, periodically disrupted by recent historical processes. Archaeologists have worked on St. Catherines Island discontinuously since 1896, when C.B. Moore conducted excavations in several prehistoric burial mounds. The University of Georgia then conducted a program of burial mound and midden excavations in 1969-1970, and the American Museum of Natural History began intensive archaeological investigations on St. Catherines Island in 1974. The ethnohistory of the Guale Indians is discussed in detail, suggesting that they were essentially a riverine people with strong internal trade contacts. Guale political organization was that of the classic Creek chiefdom. Each chiefdom maintained two principal towns, and may have been organized according to dual political organization. This interpretation contrasts sharply with the traditional view of the Guale, who are often characterized as isolated, scattered, shifting cultivators. The volume concludes with a historical outline of St. Catherines Island from the early Spanish mission period up to present times"--P. 159

Evidence That Replication-Associated Mutation Alone Does Not Explain Between-Chromosome Differences In Substitution Rates

Since Haldane first noticed an excess of paternally derived mutations, it has been considered that most mutations derive from errors during germ line replication. Miyata et al. (1987) proposed that differences in the rate of neutral evolution on X, Y, and autosome can be employed to measure the extent of this male bias. This commonly applied method assumes replication to be the sole source of between-chromosome variation in substitution rates. We propose a simple test of this assumption: If true, estimates of the male bias should be independent of which two chromosomal classes are compared. Prior evidence from rodents suggested that this might not be true, but conclusions were limited by a lack of rat Y-linked sequence. We therefore sequenced two rat Y-linked bacterial artificial chromosomes and determined evolutionary rate by comparison with mouse. For estimation of rates we consider both introns and synonymous rates. Surprisingly, for both data sets the prediction of congruent estimates of α is strongly rejected. Indeed, some comparisons suggest a female bias with autosomes evolving faster than Y-linked sequence. We conclude that the method of Miyata et al. (1987) has the potential to provide incorrect estimates. Correcting the method requires understanding of the other causes of substitution that might differ between chromosomal classes. One possible cause is recombination-associated substitution bias for which we find some evidence. We note that if, as some suggest, this association is dominantly owing to male recombination, the high estimates of α seen in birds is to be expected as Z chromosomes recombine in males