The factors affecting the performance of activated carbon prepared from oil palm empty fruit bunches for adsorption of phenol

Powdered activated carbons (PACs) were produced from oil palm empty fruit bunches (EFB) by varying the operating parameters of temperatures, CO₂ gas flow rates and activation times using 2-level full factorial experimental design. The EFB samples were first carbonized for 30 min using nitrogen gas followed by physical activation using CO₂ to optimize best production conditions. The optimum conditions for PACs produced were investigated through adsorption tests on aqueous solution of phenol. The results of this study demonstrated that the activation temperature with the range of 800–900 °C had the most significant effect on the adsorption characteristics as well as the yield of the activated carbon produced. Based on the analysis of variance (ANOVA) and model equation developed, the optimum production conditions for the EFB PAC were found to be at the activation temperature of 900 °C with CO₂ gas flow rate of 0.1 L/min and activation time of 15 min. Characterization of PAC produced showed that the activation conditions would find good-quality adsorbent with the BTE surface area of 345.1 m²/g and well forming pores distribution.     

Dynamic programming solution to the batching problem in just-in-time flow-shops

Mixed-model manufacturing systems are widely used by companies, in order to meet the customers’ demand for a variety of products, in an efficient way. This paper is concerned with a special class of mixed-model manufacturing systems: flow-shops. In a flow-shop, each product has to be processed by a number of machines, following a common route. We study the production smoothing problem under presence of non-zero setup and processing times which also vary among the products. We split the master problem into two sub-problems which are concerned with determining the batch sizes and production sequences, respectively. We develop a dynamic programming procedure to solve the batching problem, and suggest using an existing method from the current literature to solve the sequencing problem. We conduct a computational study and show that our solution approach is effective in meeting the JIT goals and efficient in its computational requirements.     

A beam search-based algorithm and evaluation of scheduling approaches for flexible manufacturing systems

This paper presents a new algorithm for the flexible manufacturing system (FMS) scheduling problem. The proposed algorithm is a heuristic based on filtered beam search. It considers finite buffer capacity, routing and sequence flexibilities and generates machine and automated guided vehicle (AGV) schedules for a given scheduling period. A new deadlock resolution mechanism is also developed as an integral part of the proposed algorithm. The performance of the algorithm is compared with several machine and AGV dispatching rules using mean flow time, mean tardiness and makespan criteria. It is also used to examine the effects of scheduling factors (i.e., machine and AGV load levels, routing and sequence flexibilities, etc.) on the system performance. The results indicate that the proposed scheduling algorithm yields considerable improvements in system performance over dispatching rules under a wide variety of experimental conditions.     

Regional Evacuation Modeling System (REMS): A decision support system for emergency area evacuations

In this paper we present a decision support system being developed at the University of Florida. The system is a PC-based software package that is capable of testing different emergency scenarios due to hurricanes, chemical accidents or nuclear accidents. The underlying models are optimization models based on a regional transportation network. One of the most significant aspects of the software is its ability to handle time dimension of the problem explicitly. It is this aspect of REMS that makes incorporation at any time of road blockages due to the presence of extremely hazardous substances or inundation of roads due to accidents or flooding possible in evacuation scenarios tested. The software has the ability to animate the evacuation process in time and display the flow of traffic on the links of the transportation network in a time-lapsed manner with color codes. Additionally REMS is also capable to animate the progress of the plume exposure pathway of an extremely hazardous substances as it evolves in time onto the evacuation network and to display the dynamic vehicle flow in time simultaneously.     

Comparison of Two Drying Schedules for European Hophornbeam (Ostrya carpinifolia Scop.) Lumber

Two types of conventional kiln-drying schedules (mild and harsh) based on moisture content (MC) were compared with regard to time, drying quality, and energy cost. The results were evaluated according to the classification of the European Drying Group. Proper drying periods of mild and harsh schedules were found to be 550 and 514 h, respectively. Evaluations in terms of drying quality indicated that better results were achieved with the mild schedule, especially when comparing drying defects and final MC. From an energy efficiency point of view, the harsh schedule, by saving 36 h of drying time, reduced electricity by 594 KWh and was therefore found to be $65 more profitable in this trial.     

Softening hard wellwaters with Moringa oleifera seed extracts

A study into the use of Moringa oleifera seed extract in the softening of hard water has been carried out with samples from 17 hand‐dug wells in Kano metropolis, Nigeria. Of the 17 samples tested, 7 contained calcium and magnesium hardness while 10 contained calcium hardness only. The softening dose of Moringa oleifera varied from 700–2000 mg/l and the required dose increased with initial hardness of the samples. The level of softening was found to be directly proportional to the dose used; and water samples with both calcium and magnesium hardness required more Moringa oleifera than samples with only calcium hardness, to achieve the same level of softening. All samples had hardness reduced to ≤ 200 mg/l CaCO₃, the highest desirable concentration of hardness in drinking water recommended by the WHO. The softening mechanism was postulated to be a combination of adsorption and precipitation of the soluble hardness causing ions to insoluble solids/flocs. The adsorption isotherm developed was linear and of the Langmuir type.     

A direct borohydride–peroxide fuel cell–LiPO battery hybrid motorcycle prototype – II

In this study, a direct borohydride–peroxide fuel cell (DBPFC)–LiPo battery hybrid motorcycle, called HYBROTO, was developed. The hybrid system was designed using a 10-cell DBPFC stack with 120 W of maximum power as the main power source, a 12 LiPo battery pack with 6300 mAh and 65 C for energy storage and as auxiliary power source, and a brushless DC (BLDC) motor. In addition, a voltage-monitoring integrated circuit for fuel cells, a battery management unit, and a motor control circuit were developed to command the DBPFC, LiPo battery, and BLDC motor, respectively. The hybrid system was managed and synchronized by a main control unit (MCU) containing a synchronous bidirectional buck–boost converter and a boost converter. For performance tests, the DBPFC–battery system and BLDC motor were installed in an electric motorcycle body. Performance tests were carried out in the hybrid system under a constant load of 60 W. The hybrid system showed a satisfactory performance under the constant load with an efficiency of 67%. However, the MCU requires further improvement to provide more stable power output. The motorcycle prototype was tested at the 2016 International Symposium on Sustainable Aviation organized by the Sustainable Aviation Research Society.     

An aluminum/cobalt/iron/nickel alloy as a precatalyst for water oxidation

Among different strategies, water splitting toward hydrogen production is a promising process to store energy from intermittent sources. However, the anodic water oxidation is a bottleneck for water splitting. In this paper, we report an aluminum/cobalt/iron/nickel alloy as a precatalyst for the electrochemical water oxidation. The alloy electrode contains different metal ions including cobalt, iron, and nickel which all are efficient for water oxidation is tested. We characterized this electrode using scanning electron microscopy, transmission electron microscopy, diffuse reflectance infrared Fourier transform spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and electrochemical methods. After stabilization, the electrode shows an onset overpotential of 200.0 mV and affords a current density of 3.5 mA cm^?2 at an overpotential of 600.0 mV in KOH solution at pH 13.     

A slurry sampling method for the determination of iron and zinc in baby food by flame atomic absorption spectrometry

A slurry sampling method is proposed for the determination of iron and zinc in baby food by flame atomic absorption spectrometry without sample digestion prior to analysis. The effect of slurry concentration (the ratio of solid sample to total slurry volume), different acids at various concentrations as diluent and the addition of dispersant on accuracy and precision were investigated. The samples were dried at 105 °C overnight and ground using an agate mortar. To obtain quantitative recoveries, 500 mg of sample was slurried in 20 ml of 0.05% Triton X-114 containing 0.1 M HNO(3), homogenised using a high-performance overhead disperser at 15,000 rpm for 5 min and directly aspirated into the flame. The accuracy of the method was tested by determination of analytes in various certified reference materials. The limits of detection of the method (N = 10; 3σ) for iron and zinc were 5.5 and 3.4 μg g(-1), respectively, using a very dilute slurry of baby food, which gave a very low background signal. Finally, the proposed method was applied to the determination of iron and zinc in different baby food samples obtained from markets in Turkey. The range of iron and zinc content for the samples were 33-76 and 15-73 μg g(-1), respectively.