Challenges and perspectives on innovative technologies for biofuel production and sustainable environmental management

Specifically, human activities, such as those in industry and transportation, have resulted in an increase in the demand for fossil fuels, resulting in severe environmental problems.Throughout this article, we discuss the potential and challenges associated with the production of biofuels from a variety of feedstocks and advances in processing technologies utilizing a range of feedstocks. Based on the conclusion of the study, we conclude that bioenergy is a green alternative to be used for diverse energy needs, once the appropriate conversion processes are applied. The production of biofuels and their use in industries and transportation have significantly reduced the use of fossil fuels. The literature review concluded that producing biofuels from energy crops and microalgae was the most efficient and attractive method. The purpose of this review is to explain all aspects of biofuels and their sustainability criteria. With a particular focus on the role of nanotechnology in biofuel production, this article discusses the most recent advances in biofuel production. A number of emerging techniques have been investigated for improving process quality, including integrated techniques, less energy-intensive distillation strategies, and the use of microorganisms in engineering. A challenging aspect of biofuel production on a large scale remains; therefore, a novel technology must be developed in order to enhance biofuel production in order to meet the challenges and meet future energy needs

Virtual mimic of lab experiment using the computer-based Aspen Plus® Sensitivity Analysis Tool to boost the attainment of experiment's learning outcomes and mitigate potential pandemic confinements

The computer-based Aspen Plus® Sensitivity Analysis Tool (APSAT) was used as a virtual environment to mimic a gas absorption lab experiment in the Unit Operations Lab within the curriculum for the Bachelor of Science in Chemical Engineering at Qatar University. A pool of 35 students enrolled in three lab sections was utilized. The approach was applied in three stages to foster the attainment of the learning outcomes of the experiment by testing and evaluating some parameters that cannot be examined using the physical lab equipment. Results show that the approach helped the students gain a profound understanding and address conceptual mistakes while discussing the results of the APSAT outputs. Students who were engaged in the APSAT activity demonstrated a strong interest in this approach. This approach can be implemented to facilitate the teaching of lab courses. Furthermore, it is a practical choice to optimize the resources and a good substitute for lab experiments in case of any pandemic, confinement or interest in testing the effects of hazardous conditions to ensure sustaining the learning outcomes from corresponding experiments.The Qatar National Library and Qatar University funded the publication of this article. Funding Open access funding is provided by the Qatar National Library.Scopus2-s2.0-8514162046

Techniques For High Quality Arabic Speech Synthesis

The paper proposes a diphone/sub-syllable method for Arabic Text-to-Speech (ATTS) systems. The proposed approach exploits the particular syllabic structure of the Arabic words. For good quality, the boundaries of the speech segments are chosen to occur only at the sustained portion of vowels. The speech segments consists of consonants-half vowels, half vowel-consonants, half vowels, middle portion of vowels, and suffix consonants. The minimum set consists of about 310 segments for classical Arabic

Techniques For High Quality Arabic Speech Synthesis

The paper proposes a diphone/sub-syllable method for Arabic Text-to-Speech (ATTS) systems. The proposed approach exploits the particular syllabic structure of the Arabic words. For good quality, the boundaries of the speech segments are chosen to occur only at the sustained portion of vowels. The speech segments consists of consonants-half vowels, half vowel-consonants, half vowels, middle portion of vowels, and suffix consonants. The minimum set consists of about 310 segments for classical Arabic

Instability in CH3NH3PbI3 perovskite solar cells due to elemental migration and chemical composition changes

Organic-inorganic halide perovskites have rapidly grown as favorable materials for photovoltaic applications, but accomplishing long-term stability is still a major research problem. This work demonstrates a new insight on instability and degradation factors in CH3NH3PbI3 perovskite solar cells aging with time in open air. X-ray photoelectron spectroscopy (XPS) has been used to investigate the compositional changes caused by device degradation over the period of 1000 hrs. XPS spectra confirm the migration of metallic ions from the bottom electrode (ITO) as a key factor causing the chemical composition change in the perovskite layer besides the diffusion of oxygen. XPS results are in good agreement with the crystallographic marks. Glow discharge optical emission spectrometry (GD-OES) has also been performed on the samples to correlate the XPS results. Based on the experimental results, fundamental features that account for the instability in the perovskite solar cell is discussed. - 2017 The Author(s).The authors are thankful to the Center for Advanced Materials (CAM), Qatar University for the laboratory support during the experimental work. The authors are also grateful to the Gas Processing Center (GPC), Qatar University for providing the XPS analysis facility. Thanks to HORIBA Scientific – Jocelyne Marciano, Sofia Gaiaschi and Patrick Chapon for the GD measurements and interpretation. This publication was also made possible by NPRP grant # 6-175-2-070 from Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors.Scopu

Conversión de Oleum papaveris seminis en ésteres metílicos mediante un proceso de esterificación: Optimización y estudio cinético

This paper presents an acid pre-treatment process and a kinetic study for the esterification reaction of Oleum papaveris seminis oil with methanol in the presence of amberlite 120 as a solid catalyst to convert the oil into methyl esters. Response surface methodology (RSM) was applied to optimize the reaction parameters, i.e. reaction time, percentage of the catalyst and volume ratio of methanol to oil. The results revealed that 0.87% w/w of catalyst concentration and 44.70% v/v of methanol to oil ratio provided final free fatty acid (FFA) contents of 0.60% w/w at 102.40 min of reaction time. It proved that the contribution of Amberlite 120 in the esterification of FFA was highly significant. The kinetics of the esterification in Oleum papaveris seminis oil with methanol in the presence of the amberlite 120 catalyst were also investigated to establish the reaction rate constant (k), reaction order, and activation energy. The study was performed under the optimized parameters at three reaction temperatures (50, 55, and 60 ºC). The value of k was in the range of 0.013 to 0.027 min-1. The first-order kinetics’ model was suitable for this irreversible FFA esterification with the activation energy of about 60.9 KJ·mol-1.En este artículo se presenta un proceso de pre-tratamiento con ácido, y un estudio cinético de la reacción de esterificación. Se utiliza Oleum papaveris seminis con metanol en presencia de Amberlite 120 como catalizador sólido para la formación de los ésteres metílicos. Se aplicó una metodología de superficie de respuesta (RSM) para optimizar los parámetros de la reacción; es decir, tiempo de reacción, porcentaje de la relación de catalizador y volumen de metanol - aceite. Los resultados mostraron que el 0,87% w/w de la concentración de catalizador y 44,70% v/v de metanol en relación al aceite dan lugar a un contenido final de ácidos grasos libres (FFA) de 0,60% w/w en 102,40 min de tiempo de reacción. Se demostró que la contribución de Amberlite 120 en la esterificación de los FFA fue altamente significativa. La cinética de la esterificación del Oleum papaveris Seminis con metanol en presencia del catalizador Amberlite 120 también se investigó para establecer la constante de velocidad de reacción (k), orden de la reacción, y la energía de activación. El estudio se realizó bajo los parámetros optimizados a tres temperaturas de reacción (50, 55, y 60 °C). El valor de la constante k fué del rango de 0.013 a 0,027 min-1. El modelo de cinética de primer orden fue el adecuado para esta esterificación FFA irreversible con una energía de activación de aproximadamente 60,9 KJ mol -1

Influence of casting solvents on co2/ch4 separation using polysulfone membranes

Polysulfone membranes exhibit resistance to high temperature with low manufacturing cost and high efficiency in the separation process. The composition of gases is an important step that estimates the efficiency of separation in membranes. As membrane types are currently becoming in demand for CO2/CH4 segregation, polysulfone will be an advantageous alternative to have in further studies. Therefore, research is undertaken in this study to evaluate two solvents: chloroform (CF) and tetrahydrofuran (THF). These solvents are tested for casting polymeric membranes from polysulfone (PSF) to separate every single component from a binary gas mixture of CO2/CH4 . In addition, the effect of gas pressure was conducted from 1 to 10 bar on the behavior of the permeability and selectivity. The results refer to the fact that the maximum permeability of CO2 and CH4 for THF is 62.32 and 2.06 barrer at 1 and 2 bars, respectively. Further, the maximum permeability of CF is 57.59 and 2.12 barrer at 1 and 2 bars, respectively. The outcome selectivity values are 48 and 36 for THF and CF at 1 bar, accordingly. Furthermore, the study declares that with the increase in pressure, the permeability and selectivity values drop for CF and THF. The performance for polysulfone (PSF) membrane that is manufactured with THF is superior to that of CF relative to the Robeson upper bound. Therefore, through the results, it can be deduced that the solvent during in-situ synthesis has a significant influence on the gas separation of a binary mixture of CO2/CH4 .Scopu

Micro-fabrication of Carbon Structures by Pattern Miniaturization in Resorcinol-Formaldehyde Gel

A simple and novel method to fabricate and miniaturize surface and sub-surface micro-structures and micro-patterns in glassy carbon is proposed and demonstrated. An aqueous resorcinol-formaldehyde (RF) sol is employed for micro-molding of the master-pattern to be replicated, followed by controlled drying and pyrolysis of the gel to reproduce an isotropically shrunk replica in carbon. The miniaturized version of the master-pattern thus replicated in carbon is about one order of magnitude smaller than original master by repeating three times the above cycle of molding and drying. The micro-fabrication method proposed will greatly enhance the toolbox for a facile fabrication of a variety of Carbon-MEMS and C-microfluidic devices.Comment: 16 pages, 5 figure

Cataract surgery by appointment – a pilot study

BACKGROUND: "Cataract Surgery by Appointment" is a new method of delivery of cataract surgery that reduces the time a patient spends in hospital by their direct arrival at the operating theatre, having self-prepared for surgery, thus avoiding admission to the ward or time spent in the Day Case Unit. The patient can stay as little as 20 minutes from their arrival to going home. We describe the process in detail, and seek to evaluate the visual outcome, safety and patient satisfaction of same. METHODS: Visual outcome and safety data were obtained from patients' medical records, prospectively. Patients were also surveyed by a questionnaire to determine their satisfaction with the service and viability as a prospect for providing a more efficient cataract surgery service. RESULTS: In 2002, fifty-one eyes of 39 consecutive patients underwent "Cataract Surgery by Appointment". There were 16 male and 23 female. The pre-operative best-corrected visual acuity was 6/9 or better in 17 (33%) eyes. The post-operative best-corrected visual acuity was 6/9 or better in 44 (86%) eyes. There were no per-operative complications. Post-operative complications occurred in 3 (6%) eyes. The average number of days from surgery to final discharge was 14.5 days. Twenty-eight (72%) completed questionnaires were returned. The results show that the majority of patients were satisfied with their overall experience of this mode of delivery for cataract surgery. CONCLUSION: "Cataract Surgery by Appointment" performed under local anaesthesia by a skilled ophthalmic surgeon appears to be safe and effective for highly selected cases. This method of delivery gave a high level of patient satisfaction, and is the ultimate form of day case cataract surgery. The method may gain widespread use should per-operative intracameral pupil dilatation prove to be effective and acceptable. Attention should be paid to risk-stratification, so complex cases are allocated more time on the operating list