scholarly journals On the performance of birch tar made with different techniques

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Patrick Schmidt ◽  
Matthias A. Blessing ◽  
Tabea J. Koch ◽  
Klaus G. Nickel

AbstractBirch tar is one of the oldest adhesives known in human history. Its production has been discussed in the framework of early complex behaviours and sophisticated cognitive capacities. The precise production method used in the Palaeolithic remains unknown today. Arguments for or against specific production pathways have been based on efficiency or process complexity. No studies have addressed the question whether birch tar made with different techniques is more or less performant in terms of its properties. We therefore investigate the adhesive performance of birch tar made with three distinct methods: the open-air condensation method and two variations of underground structures that approximate the double-pot method in aceramic conditions. We use lap-shear testing, a standard mechanical test used for testing the strength of industrial adhesives. Tar made in 1 h with the condensation method has a shear strength similar to, although slightly higher than, tar made underground if the underground process lasts for 20 h. However, tars from shorter underground procedures (5 h) are significantly less strong (by a factor of about 3). These findings have important implications for our understanding of the relationship between the investment required for Palaeolithic birch tar production and the benefits that birch tar represented for early technology. In this regard, the simple and low-investment open-air condensation method provides the best ratio.

Author(s):  
Bibian Bibeca Bumbila García ◽  
Hernán Andrés Cedeño Cedeño ◽  
Tatiana Moreira Chica ◽  
Yaritza Rossana Parrales Ríos

The objective of the work is to establish the characterization of the auditory disability and its relationship with resilience at the Technical University of Manabí. The article shows a conceptual analysis related to the inclusion and social integration of disabled students. Based on the fact that the person with disabilities grows and develops in the same way as that of people without disabilities and what usually happens is that disabled people are rejected and discriminated against based on a prefabricated and erroneous conceptualization of these people. The results associated with the application of the SV-RES test prepared by the researchers are shown (Saavedra & Villalta, 2008b). Characterization of the auditory deficit is made in the students, and the limitations that derive from it are pointed out. We analyze the particularities related to communication with students who have a hearing disability and resilience in this type of student, where some personal highlights that in this sense constitute an example of resilience. Finally, the results related to the study of the relationship between students' hearing disability and the level of resilience dimensions are shown.


Ramus ◽  
2007 ◽  
Vol 36 (1) ◽  
pp. 25-38 ◽  
Author(s):  
Myles Lavan

(BJ6.350)Those who discard their weapons and surrender their persons, I will let live. Like a lenient master in a household, I will punish the incorrigible but preserve the rest for myself.So ends Titus' address to the embattled defenders of Jerusalem in the sixth book of Josephus'Jewish War(6.328-50). It is the most substantial instance of communication between Romans and Jews in the work. Titus compares himself to the master of a household and the Jewish rebels to his slaves. Is this how we expect a Roman to describe empire? If not, what does it mean for our understanding of the politics of Josephus' history? The question is particularly acute given that this is not just any Roman but Titus himself: heir apparent and, if we believe Josephus, the man who read and approved this historical account. It is thus surprising that, while the speeches of Jewish advocates of submission to Rome such as Agrippa II (2.345-401) and Josephus himself (5.362-419) have long fascinated readers, Titus' speech has received little or no attention. Remarkably, it is not mentioned in any of three recent collections of essays on Josephus. This paper aims to highlight the rhetorical choices that Josephus has made in constructing this voice for Titus—particularly his self-presentation as master—and the interpretive questions these raise for his readers. It should go without saying that the relationship of this text to anything that Titus may have said during the siege is highly problematic. (Potentially more significant, but unfortunately no less speculative, is the question of how it might relate to any speech recorded in the commentaries of Vespasian and Titus that Josephus appears to have used as a source.) What we have is a Josephan composition that is embedded in the broader narrative of theJewish War.


2011 ◽  
Vol 68 (3) ◽  
pp. 528-536 ◽  
Author(s):  
Miguel Bernal ◽  
Yorgos Stratoudakis ◽  
Simon Wood ◽  
Leire Ibaibarriaga ◽  
Luis Valdés ◽  
...  

Abstract Bernal, M., Stratoudakis, Y., Wood, S., Ibaibarriaga, L., Uriarte, A., Valdés, L., and Borchers, D. 2011. A revision of daily egg production estimation methods, with application to Atlanto-Iberian sardine. 2. Spatially and environmentally explicit estimates of egg production. – ICES Journal of Marine Science, 68: . A spatially and environmentally explicit egg production model is developed to accommodate a number of assumptions about the relationship between egg production and mortality and associated environmental variables. The general model was tested under different assumptions for Atlanto-Iberian sardine. It provides a flexible estimator of egg production, in which a range of assumptions and hypotheses can be tested in a structured manner within a well-defined statistical framework. Application of the model to Atlanto-Iberian sardine increased the precision of the egg production time-series, and allowed improvements to be made in understanding the spatio-temporal variability in egg production, as well as implications for ecology and stock assessment.


1974 ◽  
Vol 96 (3) ◽  
pp. 722-728
Author(s):  
Rudolph E. Croteau ◽  
Herman E. Sheets

Underwater plate vibration and its associated noise are of interest for the analysis of ship structures, propeller blades, and other areas of underwater acoustics. In order to analyze the relationship between a plate vibrating underwater and the acoustic pressure in the near-field, optical interferometric holography, using a blue-green laser beam, was used to determine surface displacement for the vibrating plate, which was excited through a fluid-coupled system. Acoustic measurements of the same source were made in a water tower concurrently with the holography and later at a precision acoustic testing facility. This method permits prediction of underwater plate modal frequencies and shapes with high accuracy.


1986 ◽  
Vol 30 ◽  
pp. 59-78 ◽  
Author(s):  
Bruce Nelson

Recent discussions of the history of American communism have generated a good deal of controversy. A youthful generation of “new social historians” has combined with veterans of the Communist party to produce a portrait of the Communist experience in the United States which posits a tension between the Byzantine pursuit of the “correct line” at the top and the impulses and needs of members at the base trying to cope with a complex reality. In the words of one of its most skillful practitioners, “the new Communist history begins with the assumption that … everyone brought to the movement expectations, traditions, patterns of behavior and thought that had little to do with the decisions made in the Kremlin or on the 9th floor of the Communist Party headquarters in New York.” The “new” historians have focused mainly on the lives of individuals, the relationship between communism and ethnic and racial subcultures, and the effort to build the party's influence within particular unions and working-class constituencies. Overall, the portrait has been critical but sympathetic and has served to highlight the party's “human face” and the integrity of its members.


Author(s):  
Анна Леонидовна Краснова

В XVIII в. на основании общего интереса к святыням Востока, а также единой тенденции для крупных монастырей изготавливать гравюры на память для паломников, многие греческие гравюры свидетели русско-афонских отношений попадают на территорию Российской Империи. Сохранились такие гравюры и в Церковноархеологического кабинете Московской духовной академии, собрание которых насчитывает 29 эстампов. Пять гравюр из этого собрания имеют надписи на греческом и на славянском языке. Надписи свидетельствуют о месте и времени создания гравюры, о граверах и заказчиках, являются источниками кратких исторических сведений. В статье приведены выявленные дополнительные факты об этих гравюрах, которые свидетельствуют о наличии церковных, экономических и политических отношений на базе культурных связей между Российской Империей и странами православного Востока. The Russ has always been supporting the relationship with the Orthodox Church of the East. As a result of these connections, we have a lot of icons and other gifts from The Mount Athos, The Saint Catherine’s Monastery and others holy places. There are five Greek engravings in the collection of The Museum of Church Archaeology at the Moscow Theological Academy, which have inscriptions in Greek and Slavic. These engravings were to be spread in Slavic countries. They are dated from the 17th to the 19th century. Some of them were made in Moscow. The images and the inscriptions of the engravings are the subject of a research presented in this article.


Author(s):  
F. Vos ◽  
L. Delaey ◽  
M. De Bonte ◽  
L. Froyen

Abstract Results are presented of a project analysing the relationship between the production parameters of plasma sprayed self-lubricating Cr2O3-CaF2 coatings and their structural, wear and lubricating properties. The production method consists of a preparation step where a powder blend of the matrix material (Cr203) and solid lubricant (CaF2) is agglomerated, followed by atmospheric plasma spraying (APS) of the agglomerates. Selection of the most appropriate agglomeration and plasma spray parameters as well as the microstructure of the coatings will be discussed.


2004 ◽  
Vol 95 (2) ◽  
pp. 517-550 ◽  
Author(s):  
William M. Grove

This article first explains concepts in taxometrics, including the meaning of “taxon” in relation to taxometric procedures. It then mathematically develops the MAXSLOPE procedure of Grove and Meehl which relies on nonlinear regression of one taxometric indicator variable on another. Sufficient conditions for MAXSLOPE's validity are set forth. The relationship between the point of maximum regression slope (MAXSLOPE point) and the HITMAX cut, i.e., the point on a variable which, if used as a diagnostic cut-off score, yields maximum classification accuracy, is analyzed. A sufficient condition is given for the MAXSLOPE point to equal the HITMAX cut; however, most distributions have different MAXSLOPE and HITMAX points. Equations and an algorithm are spelled out for making a graphical test for the existence of a taxon, estimating taxometric parameters, and conducting consistency tests; the latter serve as stringent checks on the validity of a taxonic conjecture. The plausibility of assumptions made, in deriving MAXSLOPE equations, is discussed, and the qualitative effects of violations of these assumptions are explained.


2013 ◽  
Vol 12 (1) ◽  
pp. 112-132
Author(s):  
Paul Avis

AbstractHow can we explain the fact that the Anglican Covenant divides people of equal integrity and comparable wisdom around the world? We need to ask whether we have correctly understood both the ecclesiology of the Anglican Communion and the terms of the Covenant. What is implied in being a Communion of Churches, where the churches are the subjects of the relationship of communion (koinonia)? What does the Covenant commit its signatories to and, in particular, what does it say about doctrinal and ethical criteria for communion? Is it legitimate to apply biblical covenant language, in which the covenant relationship is between God and Israel, to relations between churches? By addressing some of the concerns of those who oppose it, a case is made in favour of the Covenant and some reassurances are offered. In conclusion, the mystical dimension of being in communion is affirmed.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Kongning Li ◽  
Deng Wu ◽  
Xi Chen ◽  
Ting Zhang ◽  
Lu Zhang ◽  
...  

Cell death is a critical biological process, serving many important functions within multicellular organisms. Aberrations in cell death can contribute to the pathology of human diseases. Significant progress made in the research area enormously speeds up our understanding of the biochemical and molecular mechanisms of cell death. According to the distinct morphological and biochemical characteristics, cell death can be triggered by extrinsic or intrinsic apoptosis, regulated necrosis, autophagic cell death, and mitotic catastrophe. Nevertheless, the realization that all of these efforts seek to pursue an effective treatment and cure for the disease has spurred a significant interest in the development of promising biomarkers of cell death to early diagnose disease and accurately predict disease progression and outcome. In this review, we summarize recent knowledge about cell death, survey current and emerging biomarkers of cell death, and discuss the relationship with human diseases.


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