Pattern and risk factors of acute poisoning in a tertiary hospital of Central Bangladesh

Objective: Acute poisoning is a common cause of hospital admission in Bangladesh. But, risk factors and characteristics of victims of different modes of poisoning have not been evaluated for possible intervention strategies. So, in this study we aimed to describe the pattern of acute poisoning in central Bangladesh as well as identifying risk factors for various mode of poisoning. Methods: A prospective observational study was undertaken in Dhaka Medical College Hospital in 2015. Consenting adult acute poisoning victims were included as study subjects. A pretested structured case record form was used to systematically record the cases. The poisoning cases were defined by clinical toxidrome (sympathomimetic, antimuscarinic, opioids, cholinergic, sedative, etc) during acute presentation with suspected poisoning and groups accordingly. SPSS 20 was used for data analysis and statistical tests including mean ± standard division (SD), percentage, t test and chi-square were used accordingly. Results: Total poisoning cases were 1155. Suicidal (62.25%, n = 719), commuter poisoning (24.16%, n = 279) and accidental poisoning (12.38%, n = 143) were main types of poisoning. Risk factors of suicidal poisoning were young females of 11 to 30 years, married, housewives and students (P < 0.0001). Stressful relationship was the commonest reason of suicidal poisoning. Pesticides and sedatives were frequently chosen for easy availability. Commuter poisoning was common in males and urban areas (P < 0.0001). Accidental poisoning was more in males and rural areas (P < 0.0001) and snake envenomation was the main cause. Conclusion: Poisoning burden is high in central Bangladesh. Identified risk factors will help develop poisoning prevention strategies

Boundary Lubricated Tribology of an Aluminum-Silicon Alloy Sliding Against Steel

We have slid steel pins on aluminium-silicon alloy discs in the boundary lubrication regime in the presence of one drop of oil. We have explored the effect of base oil and additivated engine oil on friction and wear and analyzed the data in terms of the formation of a mechanically mixed layer at the interface and the corrosive action of additive addition

Environmental citizenship and solid waste management in Chattogram, Bangladesh

Chattogram city is grappling with problems caused by inadequate solid waste management (SWM). Because the successful policy intervention regarding proper SWM depends on the intrinsic motivation of the city dwellers along with government intervention, the objective of this paper was to conduct an attitudinal study of the residents of Chattogram regarding their roles and responsibilities towards the SWM, and thus, the sustainable development of the city. It is a cross-sectional study based on a sample size of 150. Data was collected using a structured, pretested questionnaire. The result showed that the residents were unable to prioritize the city’s environmental problem over other problems due to the lack of knowledge and awareness about the environmental problems and its impacts on the Chattogram. However, in respect of SWM in the city, their eagerness for participation is appreciable, even though they are more dependent on government policy initiatives. An attitudinal gap was also observed here among the respondents pertaining to the vacuum of knowledge and awareness. Therefore, strong policy decisions and the awareness campaign can make people aware of their roles and responsibilities for a sustainable city and intrinsically motivate them to participate in SWM

Use of polydispersity index as control parameter to study melting/freezing of Lennard-Jones system: Comparison among predictions of bifurcation theory with Lindemann criterion, inherent structure analysis and Hansen-Verlet rule

Using polydispersity index as an additional order parameter we investigate freezing/melting transition of Lennard-Jones polydisperse systems (with Gaussian polydispersity in size), especially to gain insight into the origin of the terminal polydispersity. The average inherent structure (IS) energy and root mean square displacement (RMSD) of the solid before melting both exhibit quite similar polydispersity dependence including a discontinuity at solid-liquid transition point. Lindemann ratio, obtained from RMSD, is found to be dependent on temperature. At a given number density, there exists a value of polydispersity index (delta (P)) above which no crystalline solid is stable. This transition value of polydispersity(termed as transition polydispersity, delta (P) ) is found to depend strongly on temperature, a feature missed in hard sphere model systems. Additionally, for a particular temperature when number density is increased, delta (P) shifts to higher values. This temperature and number density dependent value of delta (P) saturates surprisingly to a value which is found to be nearly the same for all temperatures, known as terminal polydispersity (delta (TP)). This value (delta (TP) similar to 0.11) is in excellent agreement with the experimental value of 0.12, but differs from hard sphere transition where this limiting value is only 0.048. Terminal polydispersity (delta (TP)) thus has a quasiuniversal character. Interestingly, the bifurcation diagram obtained from non-linear integral equation theories of freezing seems to provide an explanation of the existence of unique terminal polydispersity in polydisperse systems. Global bond orientational order parameter is calculated to obtain further insights into mechanism for melting

Ultra mild wear in lubricated tribology of an aluminium alloy

Flat faces of steel pins were slid on an eutectic aluminium silicon alloy under lubricated condition in the 1-100 MPa mean contact pressure range and 0.2 m/s sliding speed. Two transition in wear rate were observed, at 10 MPa and 70 MPa. The wear rate in the 1-10 MPa regime was found to be very small and within the measuring instrument resolution and also insensitive to contact pressure. The regime is designated ultramild wear. Lack of plastic flow, minimal fragmentation of silicon particles, and the presence of undistorted voids on the fractured and unfractured silicon particles in the subsurface suggest that the state of stress in the near surface region is elastic. Contact mechanical calculations demonstrate that at contact pressures &lt;13.7 MPa, the system is likely to shakedown to an elastic state

Solid-liquid transition in polydisperse Lennard-Jones systems

We study melting of a face-centered crystalline solid consisting of polydisperse Lennard-Jones spheres with Gaussian polydispersity in size. The phase diagram reproduces the existence of a nearly temperature invariant terminal polydispersity (delta(t) similar or equal to 0.11), with no signature of reentrant melting. The absence of reentrant melting can be attributed to the influence of the attractive part of the potential upon melting. We find that at terminal polydispersity the fractional density change approaches zero, which seems to arise from vanishingly small compressibility of the disordered phase. At constant temperature and volume fraction the system undergoes a sharp transition from crystalline solid to the disordered amorphous or fluid state with increasing polydispersity. This has been quantified by second- and third-order rotational invariant bond orientational order, as well as by the average inherent structure energy. The translational order parameter also indicates a similar sharp structural change at delta similar or equal to 0.09 in case of T* = 1.0, phi = 0.58. The free energy calculation further supports the sharp nature of the transition. The third-order rotationally invariant bond order shows that with increasing polydispersity, the local cluster favors a more icosahedral arrangement and the system loses its local crystalline symmetry. Interestingly, the value of structure factor S(k) of the amorphous phase at delta similar or equal to 0.10 (just beyond the solid-liquid transition density at T* = 1) becomes 2.75, which is below the value of 2.85 required for freezing given by the empirical Hansen-Verlet rule of crystallization, well known in the theory of freezing

Ultra Mild Wear in Lubricated Tribology of an Aluminium Alloy

Flat faces of steel pins were slid on an eutectic aluminium silicon alloy under lubricated condition in the 1–100 MPa mean contact pressure range and 0.2 m/ s sliding speed. Two transition in wear rate were observed, at 10 MPa and 70 MPa. The wear rate in the 1–10 MPa regime was found to be very small and within the measuring instrument resolution and also insensitive to contact pressure. The regime is designated ultramild wear. Lack of plastic flow, minimal fragmentation of silicon particles, and the presence of undistorted voids on the fractured and unfractured silicon particles in the subsurface suggest that the state of stress in the near surface region is elastic. Contact mechanical calculations demonstrate that at contact pressures < 13.7 MPa, the system is likely to shakedown to an elastic state

Use of polydispersity index as control parameter to study melting/freezing of Lennard-Jones system: Comparison among predictions of bifurcation theory with Lindemann criterion, inherent structure analysis and Hansen-Verlet rule

Using polydispersity index as an additional order parameter we investigate freezing/melting transition of Lennard-Jones polydisperse systems (with Gaussian polydispersity in size), especially to gain insight into the origin of the terminal polydispersity. The average inherent structure (IS) energy and root mean square displacement (RMSD) of the solid before melting both exhibit quite similar polydispersity dependence including a discontinuity at solid-liquid transition point. Lindemann ratio, obtained from RMSD, is found to be dependent on temperature. At a given number density, there exists a value of polydispersity index (delta (P)) above which no crystalline solid is stable. This transition value of polydispersity(termed as transition polydispersity, delta (P) ) is found to depend strongly on temperature, a feature missed in hard sphere model systems. Additionally, for a particular temperature when number density is increased, delta (P) shifts to higher values. This temperature and number density dependent value of delta (P) saturates surprisingly to a value which is found to be nearly the same for all temperatures, known as terminal polydispersity (delta (TP)). This value (delta (TP) similar to 0.11) is in excellent agreement with the experimental value of 0.12, but differs from hard sphere transition where this limiting value is only 0.048. Terminal polydispersity (delta (TP)) thus has a quasiuniversal character. Interestingly, the bifurcation diagram obtained from non-linear integral equation theories of freezing seems to provide an explanation of the existence of unique terminal polydispersity in polydisperse systems. Global bond orientational order parameter is calculated to obtain further insights into mechanism for melting