Implementation of the IMO Second Generation Intact Stability Guidelines

This paper provides a discussion of the technical and theoretical ambiguities, requirements, and limitations to develop a practical implementation of the IMO Second Generation Intact Stability criteria. This discussion is the result of industry collaboration, where two implementations of the guidelines were developed jointly, albeit independently. Both implementations were then used to assess four sample cases: C11 container ship, KRISO container ship (KCS), barge, and fishing vessel, for which the detailed particulars and results are given. Conclusions on the practicalities of use, a comparison of the results, and suggestions on how the criteria might be integrated into a workflow are also given.

Development and study of the stability of comenic acid solutions

Introduction. The article presents the development of solutions based on the comenic acid substance. The criteria of the studied compositions that affect their stability during storage are evaluated within the framework of the Quality-by-Design concept. The optimal compositions of comenic acid solutions have been established.Aim. The purpose of the study is to develop solutions based on the comenic acid substance and determine the most stable variants of execution.Materials and methods. The study of comenic acid solutions was carried out by using a laboratory pH meter PB-11-P11 (SARTORIUS, Germany) and a liquid/ion chromatograph "Stayer" ("Akvilon" JSC, Russia).Results and discussion. The study made it possible to determine the most stable compositions of solutions based on the comenic acid substance and to establish optimal indicators of their stability criteria. It was found that solutions of comenic acid are the most stable in the pH range: from 4.0 to 6.0. At the same time, regardless of the studied methods of neutralization of comenic acid, solutions are unstable at concentrations of 25 mg/ml or more.Conclusion. As a result of the study, the optimal compositions of solutions based on the comenic acid substance were determined. A comparative analysis of excipients that increase the solubility of comenic acid in aqueous solvents is performed. The stability criteria of the studied solutions are established and their values for ensuring the stability of the developed drug are determined.

Phase Stability, Elastic Modulus and Elastic Anisotropy of X Doped (X = Zn, Zr and Ag) Al3Li: Insight from First-Principles Calculations

In present work, the effects of alloying elements X (X = Zn, Zr and Ag) doping on the phase stability, elastic properties, anisotropy and Debye temperature of Al3Li were studied by the first-principles method. Results showed that pure and doped Al3Li can exist and be stable at 0 K. Zn and Ag elements preferentially occupy the Al sites and Zr elements tend to occupy the Li sites. All the Cij obey the mechanical stability criteria, indicating the mechanical stability of these compounds. The overall anisotropy decreases in the following order: Al23Li8Ag > Al3Li > Al23Li8Zn > Al24Li7Zr, which shows that the addition of Zn and Zr has a positive effect on reducing the anisotropy of Al3Li. The shear anisotropic factors for Zn and Zr doped Al3Li are very close to one, meaning that elastic moduli do not strongly depend on different shear planes. For pure and doped Al3Li phase, the transverse sound velocities νt1 and νt2 among the three directions are smaller than the longitudinal sound velocity νl. Moreover, only the addition of Zn is beneficial to increasing the ΘD of Al3Li among the three elements.

HISTORICAL TRAILS OF SHIP BROACHING-TO

The article intends to bring back to light old perceptions about the “broaching-to” behaviour of ships. The signature of broaching-to is the sudden loss of controllability. The phenomenon sometimes ends with vessel capsize. The findings of an investigation into old bibliographical sources are reported, spanning more than 300 years of use of the term. Several citations have been identified in texts of nautical or related content, including voyagers’ records, nautical journals, training manuals, old encyclopaedias and even literary sources and leisure magazines. At a time when broaching-to is considered in the currently formulated new ship stability criteria at IMO, this paper provides a historical perspective on a problem that has maintained relevance despite the changes in ship technology and design.

THE DIRECT EVALUATION METHOD OF DEAD SHIP STABILITY FOR INTACT SHIP

The International Maritime Organization is currently establishing second generation intact stability criteria, the dead ship stability is considered one important criterion, so the development of its direct stability assessment regulation has become a topic undergoing close review. In this paper a peak-over-threshold (POT) method is proposed to evaluate the dead ship stability, which focuses on the statistical extrapolation that exceed the threshold, also the traditional Monte Carlo simulation is carried out to approve the method. On the basis of verification calculation of the sample ship CEHIPAR2792, the capsizing probability of a certain warship is also conducted. Moreover, the influence of initial stability height GM and effective wave slope coefficient Y on the capsizing probability is analysed. The results and the possible reason for the difference are examined. This study is expected to provide technical support for the second-generation stability criteria and establish the capsizing probability of damaged dead ship stability.

Application of the IMO Second Generation Intact Stability Criteria to a Ballast-Free Containership

A methodology is presented to systematically modify the hull shape of a ballast-free container ship, in order to manage the issue of righting lever variation in waves. The IMO second generation intact stability criteria have been identified as a stability performance assessment tool, while the vertical prismatic coefficient has been selected as the leading parameter of hull modifications to carry out the sensitivity analysis. A revised Lackenby procedure has been chosen to make systematic changes at the hull form. The outcomes of this investigation point out that the proposed procedure is suitable to enable the ship to be fully compliant with the IMO vulnerability levels with minor design adjustment.