Isobutanol and 3-methyl-1-butanol production by saccharomyces cerevisiae in aerobic condition

Alternative fuels from renewable sources are receiving public and scientific attention due to continuous depletion of petroleum fuel-reserves and environmental problem such as global warming and climate change. Higher alcohols (C3-C5) possess many advantages thus become suitable candidate in replacing gasoline as transprtation fuel. This paper investigates the production of isobutanol and 3-methyl-1-butanol as well as the toxicity of these alcohols towards Saccharomyces cerevisiae. This yeast was able to produce both alcohols with the highest concentration of 92 mg/ L (isobutanol) and 245 mg/L (3-methyl-1-butanol). Saccharomyces cerevisiae was capable to grow in more than 2% isobutanol but unable in concentration of 3-methyl-1-butanol higher than 1%

Kinetic modeling of LDPE pyrolysis using coats-Redfern method

Pyrolysis of polymer waste can potentially be a source of renewable energy, as it is a possible way to produce liquid fuel. In order to industrialize the process, the kinetic behavior of the pyrolysis has to be well understood. In this study, pyrolysis of virgin low density polyethylene (LDPE) was studied using thermogravimetric analysis (TGA). The test was carried out from 303-923 K at 20K/min in a nitrogen atmosphere. The TGA result was used to develop suitable models to calculate the activation energy, E, and pre-exponential factor, A, using Coats-Redfern method. Proximate and elemental analysis was also carried out on the LDPE sample. It was discovered that all reaction models were able to produce satisfactory linear fit of the data, with high correlation coefficients. Therefore, Coats-Redfern method cannot be used alone, but must be coupled with other methods to determine the correct reaction mechanism for the pyrolysis. By assuming first-order reaction, the calculated activation energy and pre-exponential factor are 166.75 kJ/mol and 4.97 x 1011 s-1, respectively

Performance comparison of baseline routing protocols in pocket switched network

Pocket Switched Network (PSN) is a branch of Delay Tolerant Network (DTN) which is intended to work in a challenged network. Challenged network is network with lack of infrastructure such as disaster area. As such, the network has intermittent connectivity. PSN provides a new paradigm to distribute messages in the network by taking advantage of roaming nodes from one place to another. In this paper, network performances of eight PSN routing protocols are investigated namely, First Contact, Direct Delivery, Epidemic, PRotocol using History of Encounter and Transitivity (PRoPHET), Spray and Wait, Binary Spray and Wait, Fuzzy Spray, Adaptive Fuzzy Spray and Wait. The performance metrics are packet delivery ratio, overhead ratio and average latency. Opportunistic Network Environment (ONE) simulator is used to evaluate the network performance. Experiments show that Epidemic has the best performance in term of message delivery ratio, but it has the highest overhead ratio. Direct Delivery has the lowest overhead ratio (zero overhead ratio) and PRoPHET has the lowest latency average

3D scientific data mining in ion trajectories

In physics, structure of glass and ion trajectories are essentially based on statistical analysis of data acquired through experimental measurement and computer simulation. Invariably, the details of the structure-transport relationships in the data have been mistreated in favour of ensemble average. In this study, we demonstrate a visual approach of such relationship using surface-based visualisation schemes. In particular, we demonstrate a scientific datasets of simulated 3D time-varying model and examine the temporal correlation among ion trajectories. We propose a scheme that uses a three dimensional visual representation with colour scale for depicting the timeline events in ion trajectories and this scheme could be divided into two major part such as global and local time scale. With a collection of visual examples from this study, we demonstrate that this scheme may offer an effective tool for visually mining 3D timeline events of the ion trajectories. This work will potentially form a basis of a novel analysis tool for measuring the effectiveness of visual representation to assist physicist in identifying possible temporal association among complex and chaotic atom movements in ion trajectories

A review of nanocellulose adsorptive membrane as multifunctional wastewater treatment

Dyes, inorganic and organic solvents, heavy metals and oils represent a substantial danger to water supplies, which is a major global problem. Advanced research and development in the manufacture of green-adsorptive membranes as well as simple operation, high separation efficiency, low energy consumption, eco-friendly and affordable cost have led the way to the development of sophisticated treatments for water remediation. To date, nanocellulose has been extensively investigated as excellent biomaterials in membrane filtration due to their exceptional properties such as large specific surface area, anti-fouling behaviour, high aspect ratio, high thermal resistance, outstanding mechanical properties, biodegradability and biocompatibility. The large surface area of nanocellulose contains a large number of free hydroxyl groups, which are easily modified and functionalized has been discussed. In addition, recent progresses in the application of modified nanocellulose for heavy metal removal, oily water separation and dye extractions are surveyed, since they are potentially useful as adsorbents in the filtration membrane to enhance its performance

Chemically treated chicken bone waste as an efficient adsorbent for removal of acetaminophen

Present of pharmaceutical as the emerging pollutants arise the concerns of environment community regarding the potential impact of acetaminophen (ACT) on ecological and human health. Adsorption process has been proven as an effective treatment being activated carbon as the adsorbent to remove many types of pollutant including low concentration of pollutants. However, on large scale industrial processes, utilisation of activated carbon is limited because of their high production cost. Synthesis of waste materials as a precursor of adsorbent is an attractive approach in sustainable management and economic availability. In this study, the removal of ACT from aqueous solution by chemically treated chicken bone (AC) waste was investigated. The adsorption process was conducted in a batch adsorption and affected by several experimental parameters including contact time, pH, adsorbent dose, initial concentration and temperature. With AC dosage of 0.1 g about 93 % of 1,000 mg/L ACT was removed from the aqueous solution that had pH of 2 and temperature of 25 °C. Kinetic of ACT adsorption was well described by pseudo-second order kinetic model. Meanwhile, effect of initial concentration of acetaminophen adsorption data was fitted well with Freundlich isotherm model with an R2 of 0.9909. Finally, the data obtained from effect of temperature was used to determine the adsorption thermodynamic including the enthalpy, ΔH, Gibbs energy, ΔG and entropy, ΔS. It was found that the ΔG was negative at all temperature while both, ΔH and ΔS was also negative between temperatures of 25 °C to 70 °C indicating the process of ACT adsorption was exothermic reaction and the adsorption reaction is spontaneous at low temperature

Process optimisation of effective partition constant in coconut water via progressive freeze concentration

Concentration technique via progressive freeze concentration was applied to increase the concentration of coconut water for commercialisation. The process will eliminate portion of water from coconut water and retain pure nutritional compound with high sugar content. To obtain the optimum condition, which is the objective of this study, optimisation process was conducted using Response Surface Methodology (RSM) through STATISTICA Software. RSM was utilised to optimise the process parameters for effective partition constant (K) in progressive freeze concentration (PFC) of the coconut water. The effects of circulation flowrate, circulation time, initial solution concentration and coolant temperature on effective partition constant were observed. Results show that the data adequately fit the second-order polynomial model. The linear and quadratic independent variables, circulation flowrate, circulation time, initial concentration and coolant temperature have significant effects as well as interactions on the effective partition constant. It was observed that the optimum process parameters within the experimental range for the best K would be with circulation flowrate of 3,400 mL/min, circulation time of 23 min, initial concentration of 3.4 % Brix and coolant temperature of -7 °C. Under these conditions, the K can be enhanced up to 0.3

Guidelines for Process Safety Hazard Assessment Based on Process Information

In any new chemical process development and design, process safety is a critical aspect to be considered besides economic and technical feasibility of the manufacture of the product. A lack of proper hazard assessment during the design phase may later result in accidents with disastrous consequences to workers, the public as well as the environment. Many methods have been introduced to qualitatively and quantitatively assess the safety level of processes. Despite the availability of a large amount of methods, a systematic framework that details guidelines for hazard identification, risk assessment, safety measure design, and safe critical decision-making is still missing. To address this issue, the main objective of this study was to propose a systematic framework that outlines comprehensive guidelines for assessing the safety performance of processes based on information from the piping and instrumentation diagram (P&ID). Apart from proposing the framework, appropriate strategies for minimizing safety hazards and risks are also recommended. In addition, the user is assisted in selecting the most appropriate assessment method according to his or her needs and the scope and constraints of the assessment. A case study is presented to illustrate the application of the proposed framework