Metal objects mapping after small charge explosions. A study on AISI 304Cu steel with two different grain sizes

Evidence of exposure of a metal component to a small charge explosion can be detected by observing microstructural modifications; they may be present even if the piece does not show noticeable overall plastic deformations. Particularly, if an austenitic stainless steel (or another metal having a face-centered cubic structure and a low stacking fault energy) is exposed to an explosive shock wave, high-speed deformation induces primarily mechanical twinning, whereas, in nonexplosive events, a lower velocity plastic deformation first induces slip. The occurrence of mechanical twins can be detected even if the surface is damaged or oxidized in successive events. In the present research, optical metallography (OM) and scanning electron microscopy (SEM), and scanning tunneling microscopy (STM) were used to detect microstructural modifications caused on AISI 304Cu steel disks by small-charge explosions. Spherical charges of 54.5 or 109 g TNT equivalent mass were used at explosive-to-target distances from 6.5 to 81.5 cm, achieving peak pressures from 160 to 0.5 MPa. Explosions induced limited or no macro-deformation. Two alloy grain sizes were tested. Surface OM and SEM evidenced partial surface melting, zones with recrystallization phenomena, and intense mechanical twinning, which was also detected by STM and X-ray diffraction. In the samples' interior, only twins were seen, up to some distance from the explosion impinged surface and again, at the shortest charge-to-sample distances, in a thin layer around the reflecting surface. For forensic science locating purposes after explosions, the maximum charge-to-target distance at which the phenomena disappear was singled out for each charge or grain size and related to the critical resolved shear stress for twinning.     

The issue of instability in a simple policy game between the central bank and a representative union

In the recent economic literature the independence of the central bank is often considered to be one of the most effective guarantees to achieve price stability. A strong theoretical basis for this proposition is that the monetary policy delegation given to an independent central bank is an optimal instrument to avoid the time inconsistency problem of monetary policy. This paper investigates the stability properties of this solution in a simple game in which the private sector (i.e. the trade unions) and the public sector (i.e. the central bank) simultaneously interact. A representative monopoly union is considered, and – in line with the recent economic debate – two types of unions are investigated: (i) the standard micro-founded trade union; (ii) the inflation-averse trade union. In both cases, we find that the requirement for the Nash equilibrium to be stable imposes a limit to the conservativeness of the central bank. Instability of the Nash equilibrium reveals a strategic co-ordination failure between the public and the private sector.     

Beyond Ethical Codes: The Management of Integrity in the Netherlands Tax and Customs Administration

Trust in government is foundering. Ethics codes have limited utility in bolstering public trust, and a clear correlation between such codes and changed behavior must still be established. They are a means for external oversight, but they do nothing in terms of providing an internal moral compass. To rebuild trust in government, employees must also act with integrity. Actions that are both ethical and carried out with integrity are necessary—neither is sufficient. Acknowledging this, the Dutch Tax Administration undertook a two-pronged approach focused on the management of integrity as a means to codify the operational ethics of the organization, as well as to foster shared values and behaviors. This approach is noteworthy because it guides behaviors while retaining street-level discretion. It also is the first step toward creating a bureaucracy of mutual relationships that creates an ongoing moral consciousness serving both democracy and efficiency not only through control, but also through self-reflection, interaction, and association.     

Accumulation by Dispossession and Its Limits: The Southern Africa Paradigm Revisited

The dispossession of agricultural producers from the land has long been considered a condition of successful capitalist development. The main contention of this paper is that such dispossession has in fact become the source of major developmental handicaps for at least some and possibly many countries of the global South. We develop our argument by focusing on the South(ern) African experience as a paradigmatic outlier case of accumulation by dispossession—that is, as one of its extreme instances capable of highlighting in almost ideo-typical fashion its nature and limits. After reconstructing interpretations of capitalist development in Southern Africa that in the early 1970s established the region as a paradigm of accumulation by dispossession, we discuss how useful these interpretations are for understanding the more recent developmental trajectory of South Africa. We then suggest ways in which these interpretations from the 1970s should be reformulated in light of subsequent developments. We conclude by briefly examining the theoretical and policy implications of the analysis.     

Legal Validity as Doxastic Obligation: From Definition to Normativity

The paper argues for viewing legal validityas a doxastic obligation, i.e. as the obligation toaccept a rule in legal reasoning. This notion of legalvalidity is shown to be both sufficient for thelaywers' needs and neutral in regard to varioustheories of the grounds of validity, i.e. theoriesintended to identify what rules are legally valid, byproposing different grounds for attributing validity.All of these theories, rather then being alternativedefinitions of validity, presuppose the notion hereprovided.This notion is purely normative, but it allows for theconstruction of theories of the grounds of validitywhich give due importance to social expectations andinstitutions. As an example of how this may happen,one such theory is also provided. This theory, whichis presented through a detailed example of a judicialdebate, is based upon the recognition of the(instrumental) value of co-ordination, as thenecessary way to achieve the most valuable purposes ofthe law.     

Convergence in Transition Countries – Focus on Investment: Central and Eastern Europe, 1970–1996

Our data on investment in Central and Eastern European economies reveal that, though investment rates were typically high in the 1970s, the marginal efficiency of investment was low. Investment shares begun to decline in the 1980s, before the collapse of the communist system, but there was some recovery in most countries after transition. We use the Kalman filter framework to test for convergence in investment rates. We find some evidence of convergence in Central European countries – former Czechoslovakia, Poland and the countries of the former Yugoslavia. For the remainder of the socialist bloc, however, we were unable to isolate convergence in investment shares.     

Sweat testing in addicts under methadone treatment: an Italian experience

In determining the possibility that a specific weapon was responsible for a specific injury it is often valuable to examine the damage marks left on any clothing worn by a victim. Correlating this damage both to the skin and clothing with the dimensions of the suspect weapon (if available) may help in determining these possibilities. In this work four different types of knives were used to produce damage marks on various different fabrics both stretched and loose over skin. Statistically significant differences were found between the length of wound on the skin and the corresponding damage to the fabrics when the fabric was stretched over the skin while no statistically significant differences were observed when the fabric was loose over the skin. This was true for all of the knives examined.     

The economics of collective knowledge and technological communication

Technological knowledge can be understood as a collective good when it is the outcome of the integration between internal to the firm investments in R&D and learning and the absorption of competencies and technologies provided by external organizations (such as, other firms, universities, R&D centers). Technological communication is a crucial strategy in such dynamic interaction between the firm and the system. Only under effective conditions of technological communication the private and social benefits derived from the exploitation of spillovers are higher than the private losses due to partial inappropriability. The article presents a simple microeconomic framework to understand knowledge production and distribution, integrating the effects and conditions of technological communication within a knowledge production function. The interaction between internal investments in R&D and learning, partial inappropriability, the conditions for the access to external knowledge and the exploitation of spillovers explains increasing returns in the production of knowledge.

Italy's Antitrust Chief: The Case For Regulating Fake News Online

Because of the unlimited amount of information on the internet, there is a less pluralistic exchange of different opinions than in traditional media.