Fire Safety in the Readymade Garment Sector in Bangladesh: Structural Inadequacy Versus Management Deficiency

The readymade garment (RMG) industry plays a vital role in the socio-economic development of Bangladesh, yet the sector suffers from poor fire safety records. Given the lack of fire risk assessment in the industry, this paper develops a Fire Risk Index (FRI) for individual RMG factories and surveys 60 such factories to develop an understanding of the fire safety conditions in the sector. The paper differentiates the risk factors into structural (hard) and management related (soft) parameters and develops FRIs for the structural factors. The FRI for structural parameters is then compared with the FRI for management factors, published earlier. While an overall mean FRI of 2.12 on a 4 point scale indicates that fire safety condition is quite poor, the FRI for soft parameters (1.80) are even lower than the FRI for hard parameters (2.58), indicating the critical importance of the soft parameters in fire safety assessment of the RMG factories. Within the hard parameters, there appears to be more reliance on firefighting and means for escape than on precautionary measures to contain the fire, which could explain the higher frequency of fire occurrences in the industry. FRI for both hard and soft parameters appear to follow a U shaped relationship with factory size, possibly indicating a Kuznet’s effect in fire safety in the garment sector. The poor FRI for hard factors indicates large deviations from safety requirements set in this work and asks for a stricter monitoring and enforcement regime. Improving the performance in the soft parameters, however, would require changes in the safety culture and practices.     

Synthesis and characterization of novel pH-, ionic strength and temperature- sensitive hydrogel for insulin delivery

A series of novel silane crosslinked hydrogel was prepared from kappa carrageenan (KC), acrylic acid (AA) using vinyltriethoxysilane (VTESi). Potassium persulphate initiated the grafting and copolymerization reactions between reactants. In addition, the condensation of the hydroxyl groups of KC and VTESi resulted into crosslinking. Novelty of this work is the use of VTESi as crosslinker for such a composition of hydrogel. The structure of prepared hydrogels was characterized by Fourier transform infrared spectroscopy. The analysis of spectra confirmed the presence of feed components in the prepared hydrogels. Thermogravimetric analysis showed an increase in the stability of the hydrogels either having high AA contents or crosslinker amount. The effect of feed components, pH (buffer, non-buffer), electrolytic media and temperature on the swelling behaviour of the hydrogels is reported here.Most promising results with high swelling ratio were observed in hydrogel having low monomeric ratio (KC:AA = 1:7). pH response of this hydrogel in acidic and neutral pH makes it suitable for drug delivery application. Insulin, a protein based drug was selected as a model drug. It requires its delivery in small intestine for proper action; therefore its release behaviour was studied in-vitro in simulated stomach and intestinal fluids. The release profile of insulin showed negligible release in simulated gastric fluid (SGF) and sustained release in simulated intestinal fluid (SIF). The obtained results are in good agreement with the swelling response of this hydrogel. The weak structure of this hydrogel makes it preferable for drug delivery, as it is able to get crumbled after releasing the drug for 6 h at neutral pH.     

An experimental study on thermal mixing in a square body inserted inclined narrow channels

An experimental study has been performed on thermal mixing phenomena in a narrow channel by twin-jets at different temperatures. Water was used as working fluid and it is supplied by hot and cold taps. The channel has a circular exit hole to supply continuity of mass. An adiabatic square shaped object, which in the thickness of the channel, is inserted into the channel to control thermal mixing as a passive technique. Other parameters in experiments are ratio of flow rate of inlet fluid, inclination angle of the channel, jet diameter and jet velocities. Finally, a thermal mixing index was calculated from measured values of temperatures for different parameters. Temperature distribution is obtained for whole channel and isotherms are plotted. The obtained results indicated that higher thermal mixing efficiency is observed for ? = 60^o and inserted body can be a control parameter for thermal mixing for the same geometrical parameters.     

Microstructural and wear properties of the Al-B4C composite coating produced by hot-press sintering on AA-2024 alloy

Journal of Mechanical Science and Technology - In this study, the surface of an AA-2024 alloy was covered with reinforced composite coating using hotpress sintering method. Al and B4C powders were...     

Magneto-Acoustic Properties of UCuGe Single Crystal

We report on results of sound velocity and sound-attenuation measurements performed on the antiferromagnetic (T _N =48 K) UCuGe. The measurements have been done on a UCuGe single crystal at different frequencies for longitudinal ultrasound waves propagating along the [001] direction in static (up to 18 T) and pulsed (up to 60 T) magnetic fields applied along the same direction. The temperature dependences of the sound velocity and attenuation display a pronounced anomaly at T _N , which is evidence for a strong magneto-elastic interaction. The pulse-field measurements at 4.2 K show a minimum in the sound velocity followed by a jump-like anomaly at 37 T, and another kink-like anomaly at 48–49 T. These anomalies are due to field-induced spin rearrangements as measured in magnetization studies. In the paramagnetic state (T>T _N ), both acoustic characteristics show large frequency-dependent changes revealing the presence of an unusual relaxation mechanism which might be due to vacancy dynamics.     

A negative dual rectangle cancellation algorithm for the linear assignment problem

In this paper, we consider three alternative primal models and their corresponding alternative dual models for the linear assignment problem. We then define the concept of Negative Dual Rectangle (NDR) and suggest an algorithm that solves two of these dual problems by repeatedly finding and cancelling NDRs until it yields an optimal solution to the assignment problem. The algorithm is simple, flexible, efficient, and unified. We also introduce the notion of partial zero cover as an interpretation of an NDR. We then introduce some heuristic methods for finding NDRs. We also state and prove a lemma to establish the optimal use of an NDR. Furthermore, we show that on a new class of benchmark instances that is introduced in this paper the running time of our algorithm is highly superior to a well-known pure shortest path algorithm.     

Lagrangian relaxation and constraint generation for allocation and advanced scheduling

Diverse applications in manufacturing, logistics, health care, telecommunications, and computing require that renewable resources be dynamically scheduled to handle distinct classes of job service requests arriving randomly over slotted time. These dynamic stochastic resource scheduling problems are analytically and computationally intractable even when the number of job classes is relatively small. In this paper, we formally introduce two types of problems called allocation and advanced scheduling, and formulate their Markov decision process (MDP) models. We establish that these MDPs are “weakly coupled” and exploit this structural property to develop an approximate dynamic programming method that uses Lagrangian relaxation and constraint generation to efficiently make good scheduling decisions. In fact, our method is presented for a general class of large-scale weakly coupled MDPs that we precisely define. Extensive computational experiments on hundreds of randomly generated test problems reveal that Lagrangian decisions outperform myopic decisions with a statistically significant margin. The relative benefit of Lagrangian decisions is much higher for advanced scheduling than for allocation scheduling.     

Improved transesterification of waste cooking oil into biodiesel using calcined goat bone as a catalyst

In this study, potassium hydroxide-treated animal bones were employed? as a solid heterogeneous catalyst in transesterification of waste cooking oil. This catalyst was characterized by the Fourier-transform infrared spectroscopy (FTIR), and it displayed high-catalytic activity for biodiesel production. Optimum conditions for biodiesel production were catalyst loading 6.0% (w/w) of oil, methanol/oil molar ratio 9:1, calcination temperature 800°C, reaction temperature 65°C, and reaction time of 5 h, which gave maximum biodiesel yield of 84%. Reusability of the catalyst was also confirmed by repeated use of the same catalyst three times without losing much of its activity. Hence, calcined goat bones were found to be a potentially applicable catalyst for biodiesel production at industrial scale.