Search Results (5)

Risk assessment is a critical sub-process in information security risk management (ISRM) that is used to identify an organization’s vulnerabilities and threats as well as evaluate current and planned security controls. Therefore, adequate resources and return on investments should be considered when reviewing assets. However, many existing frameworks lack granular guidelines and mostly operate on qualitative human input and feedback, which increases subjective and unreliable judgment within organizations. Consequently, current risk assessment methods require additional time and cost to test all information security controls thoroughly. The principal aim of this study is to critically review the Information Security Control Prioritization (ISCP) models that improve the Information Security Risk Assessment (ISRA) process, by using literature analysis to investigate ISRA’s main problems and challenges. We recommend that designing a streamlined and standardized Information Security Control Prioritization model would greatly reduce the uncertainty, cost, and time associated with the assessment of information security controls, thereby helping organizations prioritize critical controls reliably and more efficiently based on clear and practical guidelines. Full article

In this study, concrete was selected to investigate the real-time splitting tensile mechanical and fracture behaviours of brittle materials using the Brazilian test under concentrated and distributed boundary conditions. The digital image correlation (DIC) method was adopted to evaluate the tensile strength and failure process in Brazilian tests using a high-resolution camera. The DIC results showed that the position of the crack initiation randomly occurred at the centre of a disc and at the boundary in Brazilian tests with concentrated loads (BTC). Comparatively, the crack initiated at the centre of discs in most Brazilian tests with distributed loads (BTD), as validated by the DIC results. Our results indicated that the average nominal tensile strength of specimens cracking at the boundary was larger than that of specimens cracking at the centre in the BTC, suggesting that the nominal tensile strength measured by the Brazilian test was related to the failure process of the discs. Moreover, this study demonstrated that the tensile strength measured by the Brazilian test was dependent on the boundary conditions. The equation recommended by the ISRM (International Society for Rock Mechanics) might slightly overestimate the tensile strength of brittle materials based on the pure elastic theory and hyperbolic-distributed loading conditions at the boundaries. Full article

Uniaxial compressive strength (UCS) testing requires high-quality core samples, which is a difficult task for weak, highly fractured, thinly bedded, foliated, and weathered rocks. In addition, it is time-consuming and expensive. Because of the good relationship between rock point load strength (PLS) and UCS, the PLS could be used to estimate rock UCS quickly. The lump structure and layer structure of carbonaceous slate are revealed in the tunnels of the China–Laos Railway in the Laos Luang Prabang Suture Zone as one of the important factors leading to tunnel squeezing deformation and support structures. To reveal the relationship between the PLS and UCS of carbonaceous slate in the Luang Prabang Suture Zone, PLS tests and UCS tests of lump-structure carbonaceous slate (lamina plane inconspicuous) and layer-structure carbonaceous slate (lamina plane conspicuous) were performed. Results show that the I_s(50) of lump-structure carbonaceous slate ranged from 0.06 MPa to 0.30 Mpa, the I_s(50) of layer-structure carbonaceous slates which were loaded perpendicular to the lamina plane ranged from 0.64 MPa to 1.25 MPa, the I_s(50) of layer-structure carbonaceous slates which were loaded parallel to the lamina plane ranged from 0.49 MPa to 0.71 MPa, and the correction power index m ranged from 0.42 to 0.51 with an average value of 0.47. Four correlation expressions of carbonaceous slate relationships between PLS and UCS were fitted by zero-intercept linear expression, nonzero intercept linear expression, power expression, and logarithmic expression, and the calculation results were compared with results calculated by the International Society of Rock Mechanics (ISRM) correlation equation. It is concluded that the correlation equation between UCS and PLS recommended by ISRM specifications easily causes soft rock strength overestimation, which affects the correct evaluation of the surrounding rock property and the structural design safety of tunnels and underground projects. The zero-intercept linear equation UCS = 18.45I_s(50) has better goodness of fit and higher accuracy in predicting the UCS of the carbonaceous slate in the Luang Prabang Suture Zone. Full article

The present study investigates the aggregate suitability and geochemical characteristics of limestone (LS) from the Samana Suk Formation, Pakistan, for the construction industry. With the advent of CPEC, the demand for construction materials has seen a manifold increase. The Sheikh Budin Hills and Trans Indus Ranges comprise huge deposits of limestone and provide great potential for source rocks for construction materials in the region. In the Upper Indus Basin of Pakistan, the Samana Suk Formation is acknowledged as the most significant carbonate deposits of Mesozoic strata. The results of aggregate parameters reveal that specific gravity (SG = 2.6); water absorption (WA = 0.47%); bulk density (BD = 1.58 g/cm³); flakiness index (FI = 16.8%); elongation index (EI = 16.39%); soundness (S = 1.6%); aggregate impact value (AIV = 14%); Los Angeles Abrasion value (LAAV = 23.51%); clay lumps (CL = 0.35%); uniaxial compressive strength (UCS = 86.7 MPa); point load test (PLT = 5.18 MPa); ultrasonic pulse velocity (UPV = 5290 m/s); and Schmidt hammer rebound test (SHRT = 49 N) are in accordance with the ASTM, ISRM, and BSI. Petrographically, the LS is dominantly composed of ooids, peloids, bioclasts, and calcite mineral (CaCO₃) with a trace concentration of dolomite [(Ca,Mg)CO₃]. The mineralogical and geochemical study (n = 18) revealed that the LS is dominantly composed of calcite (95.81%); on average, it is composed of 52.08 wt.% CaO; 1.13 wt.% SiO₂; 0.66 wt.% MgO; 0.80 wt.% Al₂O₃; and 0.76 wt.% Fe₂O₃, and loss on ignition (LOI) was recorded as 42.13 wt.%. On the other hand, P₂O₅, TiO₂, MnO, K₂O and Na₂O were found in trace amounts. The regression analysis demonstrated that the empirical correlation equation for estimating uniaxial compressive strength with ultrasonic pulse velocity is more reliable than the Schmidt hammer rebound test and point load test. Consequently, the feasibility of using LS of the Samana Suk Formation as an aggregate for construction materials and cement manufacturing is recommended based on the testing results of mechanical, physical, and geochemical properties. Full article

The objective of the current study was to compare results relating to the compressive and tensile strength of rocks obtained during research undertaken according to Polish Standards (as part of the European standards known as Eurocodes), American Society for Testing and Materials (ASTM) Standards, and the recommendations of the International Society for Rock Mechanics (ISRM). A total of 130 experiments for uniaxial compression on axisymmetric samples, point loads, and transverse compression (so-called Brazilian tests) were performed on rock samples comprising granite, limestone, and sandstone. Geometric properties of the samples were selected depending on the applied research method, and the relationship between the specimen’s slenderness and shape, and the obtained values of compressive and tensile strength, were analyzed. The results of the study showed that values of compressive and tensile strength obtained in a laboratory depend significantly on specimen slenderness, different values of which are imposed by various ISRM standards and recommendations, wherein this sensitivity was much higher in the case of compressive strength. The study also raised doubt about the usefulness of the so-called point load test as a method for determination of the compressive strength of rocks and potential estimation of the tensile strength. Full article