Investigation of photon, neutron and proton shielding features of H3BO3–ZnO–Na2O–BaO glass system

The current study aims to explore the shielding properties of multi-component borate-based glass series. Seven glass-samples with composition of (80-y)H3BO3–10ZnO–10Na2O–yBaO where (y = 0, 5, 10, 15, 20, 25 and 30 mol.%) were synthesized by melt-quench method. Various shielding features for photons, neutrons, and protons were determined for all prepared samples. XCOM, Phy-X program, and SRIM code were performed to determine and explain several shielding properties such as equivalent atomic number, exposure build-up factor, specific gamma-ray constants, effective removal cross-section (SR), neutron scattering and absorption, Mass Stopping Power (MSP) and projected range. The energy ranges for photons and protons were 0.015–15 MeV and 0.01–10 MeV, respectively. The mass attenuation coefficient (µ/?) was also determined experimentally by utilizing two radioactive sources (166Ho and 137Cs). Consistent results were obtained between experimental and XCOM values in determining µ/? of the new glasses. The addition of BaO to the glass matrix led to enhance the µ/? and specific gamma-ray constants of glasses. Whereas the remarkable reductions in SR, MSP, and projected range values were reported with increasing BaO concentrations. The acquired results nominate the use of these glasses in different radiation shielding purposes

Exposure assessment of radon in the drinking water supplies: a descriptive study in Palestine

<p>Abstract</p> <p>Background</p> <p>Radon gas is considered as a main risk factor for lung cancer and found naturally in rock, soil, and water. The objective of this study was to determine the radon level in the drinking water sources in Nablus city in order to set up a sound policy on water management in Palestine.</p> <p>Methods</p> <p>This was a descriptive study carried out in two phases with a random sampling technique in the second phase. Primarily, samples were taken from 4 wells and 5 springs that supplied Nablus city residents. For each source, 3 samples were taken and each was analyzed in 4 cycles by RAD 7 device manufactured by Durridge Company. Secondly, from the seven regions of the Nablus city, three samples were taken from the residential tap water of each region. Regarding the old city, ten samples were taken. Finally, the mean radon concentration value for each source was calculated.</p> <p>Results</p> <p>The mean (range) concentration of radon in the main sources were 6.9 (1.5-23.4) Becquerel/liter (Bq/L). Separately, springs and wells' means were 4.6 Bq/L and 9.5 Bq/L; respectively. For the residential tap water in the 7 regions, the results of the mean (range) concentration values were found to be 1.0 (0.9-1.3) Bq/L. For the old city, the mean (range) concentration values were 2.3 (0.9-3.9) Bq/L.</p> <p>Conclusions</p> <p>Except for Al-Badan well, radon concentrations in the wells and springs were below the United State Environmental Protection Agency maximum contaminated level (U.S EPA MCL). The level was much lower for tap water. Although the concentration of radon in the tap water of old city were below the MCL, it was higher than other regions in the city. Preventive measures and population awareness on radon's exposure are recommended.</p

Manufacturing and Supply Chain Flexibility: Building an Integrative Conceptual Model Through Systematic Literature Review and Bibliometric Analysis

The purpose of this study is twofold: first, to establish the current themes on the topic of manufacturing and supply chain flexibility (MSCF), assess their level of maturity in relation to each other, identify the emerging ones and reflect on how they can inform each other, and second, to develop a conceptual model of MSCF that links different themes connect and highlight future research opportunities. The study builds on a sample of 222 articles published from 1996 to 2018 in international, peer-reviewed journals. The analysis of the sample involves two complementary approaches: the co-word technique to identify the thematic clusters as well as their relative standing and a critical reflection on the papers to explain the intellectual content of these thematic clusters. The results of the co-word analysis show that MSCF is a dynamic topic with a rich and complex structure that comprises five thematic clusters. The value chain, capability and volatility clusters showed research topics that were taking a central role in the discussion on MSCF but were not mature yet. The SC purchasing practices and SC planning clusters involved work that was more focused and could be considered more mature. These clusters were then integrated in a framework that built on the competence–capability perspective and identified the major structural and infrastructural elements of MSCF as well as its antecedents and consequences. This paper proposes an integrative framework helping managers keep track the various decisions they need to make to increase flexibility from the viewpoint of the entire value chain

Application of CR-39 Microfilm for Rapid Discrimination Between Alpha-Particle Sources

This work presents a new technique for discriminating between alpha particles of different energy levels. In a first study, two groups of alpha particles emitted from radium-226 and americium-241 sources were successfully separated using a CR-39 microfilm of appropriate thickness. This thickness was adjusted by chemical etching before and after irradiation so that lower-energy particles were stopped within the detector, while higher-energy particles were revealed on the back side of the detector. The number of tracks on the front side of the microfilm represented all alpha particles incident on that side from the two sources. However, the number of tracks on the back side of the microfilm represented only the long-range alpha particles of higher energy that arrived at that side. Therefore, by subtracting the number of tracks on the back side from the number of tracks on the front side, one could easily determine the number of tracks for the short-range alpha particles of lower energy that remained embedded in the microfilm. Discrimination of the two energy levels is thus achieved in a simple, fast, and reliable process

The role of entrepreneurial orientation in developing SMEs resilience capabilities throughout COVID-19

Through the lens of entrepreneurial orientation, this study investigates operational practices that (small and medium-sized enterprises) have either adopted or improvised to support small and medium-sized enterprises’ resilience in the face of coronavirus disease 2019. Qualitative data were collected through 43 semi-structured interviews with entrepreneurial resource providers, owners and managers of several small and medium-sized enterprises across different industrial sectors in Jordan. The study contributes to the further understanding of small and medium-sized enterprises’ resilience by conceptually advocating a five-pillars practitioner-grounded framework of small and medium-sized enterprises’ resilience capability (efficiency-based capability, adaptive-capability, collaborative-capability, change-capability and learning-capability). Entrepreneurial orientation has been found to transition and mobilise small and medium-sized enterprises’ resilience to survive major disruptions and threats. Entrepreneurial orientation, in this study, grounded on risk-taking, innovation and proactivity, facilitates developing new capabilities that shield the firm against different threats. Practically, the study suggests several recommendations for small and medium-sized enterprises to meet the challenges of coronavirus disease 2019 and similar future major shocks. Notably, the study suggests that small and medium-sized enterprises should balance short-term operational actions with long-term strategic thinking to build a resilience capability pool

Effectiveness of Consistency Measures in Crash Prediction Models for Two-Lane Highways in Palestine

Crash prediction models (CPMs) are important tools to predict the safety performance of highways based on their operational and geometric characteristics. Most of these models use geometric design characteristics to predict the number of crashes. However, few studies have identified the effectiveness of geometric design consistency measures in explaining crash occurrence probability and crash prediction. Crash prediction models that incorporate design consistency measures for rural two-lane, two-way roadways in the West Bank of Palestine have been developed. This study compares the effectiveness of the resulting models with those which rely on geometric design characteristics only. Approximately 118�km length of two-lane rural highways in the West Bank was selected covering a variety of highway classifications, locations, and characteristics. Different design consistency measures were considered in the developed CPM. The generalized linear regression modeling approach was used, and different mathematical forms were tested. The research presents a quantitative comparison between CPMs that explicitly consider design consistency with the Highway Safety Manual models, which use geometric design characteristics. The study proposes an approach to identify geometrically inconsistent locations using the safety-consistency factor. The results indicate that geometric consistency measures could provide more reliable crash prediction models, thus predicting collision potential more accurately. � 2018, King Fahd University of Petroleum & Minerals.Scopu

CFD-based investigation of heat transfer characteristics of flue gas-water eat exchanger panels produced with a novel manufacturing proces

This study describes the characteristics of a panel geometry obtained by a novel manufacturing process for the development of ultra-compact flue gas-water condensing heat exchangers. In this process two stainless steel sheets are prepared and stacked and then brazed together in a special pattern outlining a desired configuration of water ducts and connecting manifolds. By injecting pressurized fluid to the clearance between the bonded sheets, the sheets are deformed and the enlarged clearance becomes a flow pass of water. By stacking several such bonded panels together, the clearances between them work as flue-gas passages. The principle of using this process is that panels can be produced more economically and with sufficient control over the parameters of the obtained geometry as well as the strength. Because of this manufacturing process, the cross-section of the water duct obtains a special noncircular shape, so the heat transfer characteristics must be specifically assessed for the new geometry, in order to qualify the new design. Through CFD analysis, we evaluate the heat transfer performance of the water duct in the novel heat exchanger by comparing with the heat transfer performance of a standard circular duct which has the same hydrodynamic diameter as the investigated water duct.Design EngineeringIndustrial Design Engineerin

Simple equations for predicting the rotational ductility of fiber-reinforced-polymer strengthened reinforced concrete joints

Achieving a certain limit of rotational ductility in retrofitted reinforced concrete (R.C) joints is very important in the design of earthquake-resistant structures. Strengthening of R.C joints using wraps of fiber-reinforced polymers (FRP) is a common attractive technique and has an effect on the ductility of such joints. This study focuses on developing simple conceptual equations to predict the ductility of exterior reinforced concrete (R.C) beamcolumn joints as a function of the applied FRP. The equations are derived based on statistical regression through parametric study using results from a high-fidelity finite element model created using ABAQUS. The validated model includes material and geometric nonlinearities, in addition to the use of realistic nonlinear contact behavior between FRP and concrete. The proposed simple equations can be used as an initial conceptual design step for checking the adequacy of R.C beam-column joints in seismic design of R.C buildings. The proposed equations consider FRP, relative column-to-beam inertia, and transverse reinforcement in the beam and joint as the main parameter. This study defines the types of failure based on the ductility, and it develops the equations for ductile and brittle failures for both CFRP-strengthened joints and non-strengthened joints. This research confirms quantitatively the effectiveness of using CFRP to increase the ductility in most cases of the R.C beamcolumn joints. However, contribution of the CFRP is limited for some cases