• Energy Research

Calcium based catalysts have been studied as promising heterogeneous catalysts for production of methyl esters via transesterification; however a few were explored on catalyst synthesis with high surface area, less particle size, and Ca leaching analysis. In this work, an active Razor shell CaO with crystalline size of 87.2 nm, SBET of 92.63 m2/g, pore diameters of 37.311 nm, and pore volume of 0.613 cc/g was synthesized by a green technique “calcination-hydro aeration-dehydration.” Spectrographic techniques TGA/DTA, FTIR, SEM, XRD, BET&BJH, and PSA were employed for characterization and surface morphology of CaO. Two-step transesterification of Jatropha curcas oil was performed to evaluate CaO catalytic activity. A five-factor-five-level, two-block, half factorial, central composite design based response surface method was employed for experimental analysis and optimization of Jatropha methyl ester (JME) yield. The regression model adequacy ascertained thru coefficient of determination (R2: 95.81%). A JME yield of 98.80% was noted at C (3.10 wt.%), M (54.24 mol./mol.%), T (127.87 min), H (51.31°C), and R (612 rpm). The amount of Ca leached to JME during 1st and 4th reuse cycles was 1.43 ppm ± 0.11 and 4.25 ppm ± 0.21, respectively. Higher leaching of Ca, 6.67 ppm ± 1.09, was found from the 5th reuse cycle due to higher dispersion of Ca2+; consequently JME yield reduces to 76.40%. The JME fuel properties were studied according to biodiesel standards EN 14214 and comply to use as green biodiesel.

This paper presents the result of investigations carried out in studying the emission and performance of diesel engine using the castor biodiesel and its blend with diesel from 0% to 40% by volume. The acid-based catalyzed transesterification system was used to produce castor biodiesel and the highest yield of 82.5% was obtained under the optimized condition. The FTIR spectrum of castor biodiesel indicates the presence of C=O and C–O functional groups, which is due to the ester compound in biodiesel. The smoke emission test revealed that B40 (biodiesel blend with 40% biodiesel and 60% diesel) had the least black smoke compared to the conventional diesel. Diesel engine performance test indicated that the specific fuel consumption of biodiesel blend was increased sufficiently when the blending ratio was optimized. Thus, the reduction in exhaust emissions and reduction in brake-specific fuel consumption made the blends of caster seed oil (B20) a suitable alternative fuel for diesel and could help in controlling air pollution.

In this work, polylactic acid (PLA) reinforced cellulose nanowhiskers (CNW) were prepared through solution casting technique. The CNW was first isolated from oil palm empty fruit bunch microcrystalline cellulose (OPEFB-MCC) by using 64% H2SO4 and was designated as CNW-S. The optical microscopy revealed that the large particle of OPEFB-MCC has been broken down by the hydrolysis treatment. The atomic force microscopy confirmed that the CNW-S obtained is in nanoscale dimension and appeared in individual rod-like character. The produced CNW-S was then incorporated with PLA at 1, 3, and 5 parts per hundred (phr) resins for the PLA-CNW-S nanocomposite production. The synthesized nanocomposites were then characterized by a mean of tensile properties and thermal stability. Interestingly to note that incorporating of 3 phr/CNW-S in PLA improved the tensile strength by 61%. Also, CNW-S loading showed a positive impact on the Young's modulus of PLA. The elongation at break (Eb) of nanocomposites, however, decreased with the addition of CNW-S. Field emission scanning electron microscopy and transmission electron microscopy revealed that the CNW-S dispersed well in PLA at lower filler loading before it started to agglomerate at higher CNW-S loading (5phr). The DSC analysis of the nanocomposites obtained showed that Tg,Tcc and Tm values of PLA were improved with CNW-S loading. The TGA analysis however, revealed that incopreated CNW-S in PLA effect the thermal stability (T10,T50 and Tmax) of nanocomposite, where it decrease linearly with CNW-S loading.

In this work, polylactic acid (PLA) composites filled with microcrystalline cellulose (MCC) from oil palm biomass were successfully prepared through solution casting. Fourier transform infrared (FT-IR) spectroscopy indicates that there are no significant changes in the peak positions, suggesting that incorporation of MCC in PLA did not result in any significant change in chemical structure of PLA. Thermogravimetric analysis was conducted on the samples. The T50 decomposition temperature improved with addition of MCC, showing increase in thermal stability of the composites. The synthesized composites were characterized in terms of tensile properties. The Young's modulus increased by about 30%, while the tensile strength and elongation at break for composites decreased with addition of MCC. Scanning electron microscopy (SEM) of the composites fractured surface shows that the MCC remained as aggregates of crystalline cellulose. Atomic force microscopy (AFM) topographic image of the composite surfaces show clustering of MCC with uneven distribution.

The physiochemical properties of biodiesel are significantly influenced by its fatty acid composition (FAC). This research investigates FAC of Jatropha biodiesel (JB) synthesized using feedstocks originated from the east (JBEM) and west (JBWM) Malaysian regions together with biofuel properties. The critical properties of pure biodiesels and blends were analysed according to ASTM D6751/EN 14214 standards. The JB properties were precisely regulated by its FAC features such as saturated fatty acids (SFAs), unsaturated fatty acids (USFAs), degree of unsaturation, and long chain saturated factor. The influence of SFA and USFA was inversely associated over biodiesel properties. The presence of higher SFA greatly affects biodiesel properties like the cetane number, cold filter plugging point, kinematic viscosity, density, cloud point, and pour point; conversely, the fuel properties such as oxidation stability, iodine value, acid value, water content, and flash point were improving with USFA contents. Blending of biofuels with petro diesels considerably improved their fuel properties.

Les catalyseurs hétérogènes sont souvent utilisés dans leur ensemble pour produire du biodiesel à partir d'huiles brutes végétales non comestibles telles que l'huile de Jatropha curcas (JCO). Dans cette étude, un catalyseur de CaO hétérogène actif a été synthétisé à partir d'un coquillage de biodiversité tropicale Anadara granosa (A.granosa). L'efficacité catalytique de A.granosa CaO a été étudiée dans la transestérification de JCO sous forme de biodiesel. Le catalyseur A.granosa CaO a été synthétisé en utilisant le protocole « Calcination – hydratation – déshydratation ». La caractérisation spectrale du catalyseur a été étudiée en utilisant des techniques spectrographiques FT-IR, SEM, BET et BJH. La conception expérimentale a été exécutée avec quatre paramètres de réaction qui comprennent la concentration du catalyseur (CC), le taux de méthanol (MR), le temps de transestérification (TT) et la température de réaction (RT). Les réactions de transestérification de JCO ainsi que l'impact des paramètres de réaction sur le rendement en biodiesel de Jatropha (JBY) ont été analysés. La suffisance des résultats expérimentaux était conforme grâce à des tests de validation séquentiels, en conséquence, une moyenne de 96,2% JMY a été notée dans des conditions paramétriques optimales, CC de 3wt. %, TT de 120 min, MR de 5 mol. et RT de 60ºC à une vitesse d'agitation constante de 300 tr/min. Une JMY moyenne de 87,6 % a été obtenue à partir du catalyseur A.granosa CaO lors de leurs études de recyclage et de réutilisation jusqu'au troisième cycle de réutilisation. Los catalizadores heterogéneos se utilizan a menudo en general para producir biodiésel a partir de aceites crudos vegetales no comestibles, como el aceite de Jatropha curcas (JCO). En este estudio, se sintetizó un catalizador de CaO heterogéneo activo a partir de conchas marinas de biodiversidad tropical Anadara granosa (A.granosa). Se investigó la eficiencia catalítica de A.granosa CaO en la transesterificación de JCO como biodiesel. El catalizador de CaO de A.granosa se sintetizó utilizando el protocolo 'Calcinación – hidratación – deshidratación'. La caracterización espectral del catalizador se investigó empleando técnicas espectrográficas FT-IR, SEM, BET y BJH. El diseño experimental se ejecutó con cuatro parámetros de reacción que incluyen concentración de catalizador (CC), relación de metanol (MR), tiempo de transesterificación (TT) y temperatura de reacción (RT). Se analizaron las reacciones de transesterificación de JCO, así como el impacto de los parámetros de reacción en el rendimiento de biodiésel de Jatropha (JBY). La suficiencia de los resultados experimentales se conformó a través de pruebas de validación secuencial, como resultado, se observó un promedio de 96.2% de JMY en condiciones paramétricas óptimas, CC de 3wt. %, TT de 120 min, MR de 5 mol. y RT de 60ºC a una velocidad de agitación constante de 300rpm. Se obtuvo un JMY medio del 87,6% del catalizador de Cao de A.granosa durante sus estudios de reciclaje y reutilización hasta el tercer ciclo de reutilización. Heterogeneous catalysts are often used at large to produce biodiesel from non-edible vegetable crude oils such as Jatropha curcas oil (JCO). In this study, an active heterogeneous CaO catalyst was synthesized from a tropical biodiversity seashells Anadara granosa (A.granosa). The catalytic efficiency of A.granosa CaO was investigated in transesterification of JCO as biodiesel. The A.granosa CaO catalyst was synthesized using 'Calcination – hydration – dehydration' protocol. The spectral characterization of the catalyst were investigated by employing FT-IR, SEM, BET and BJH spectrographic techniques. The experimental design was executed with four reaction parameters that include catalyst concentration (CC), methanol ratio (MR), transesterification time (TT) and reaction temperature (RT). The JCO transesterification reactions as well as impact of reaction parameters on the Jatropha biodiesel yield (JBY) were analyzed. The sufficiency of the experimental results conformed through sequential validation tests, as a result, an average of 96.2% JMY was noted at optimal parametric conditions, CC of 3wt. %, TT of 120 min, MR of 5 mol. and RT of 60ºC at a constant agitation speed of 300rpm. An average JMY of 87.6% was resulted from the A.granosa CaO catalyst during their recycling and reuse studies up to third reuse cycle. غالبًا ما تستخدم المحفزات غير المتجانسة بشكل عام لإنتاج الديزل الحيوي من الزيوت الخام النباتية غير الصالحة للأكل مثل زيت جاتروفا كركاس (JCO). في هذه الدراسة، تم تصنيع محفز CaO غير متجانس نشط من أصداف البحر الاستوائية للتنوع البيولوجي Anadara granosa (A.granosa). تم التحقيق في الكفاءة التحفيزية لـ A.granosa CaO في تحويل JCO كديزل حيوي. تم تصنيع محفز A.granosa CaO باستخدام بروتوكول "التكليس – الترطيب – التجفيف". تم التحقيق في التوصيف الطيفي للمحفز من خلال استخدام تقنيات FT - IR و SEM و BET و BJH الطيفية. تم تنفيذ التصميم التجريبي بأربعة معلمات تفاعل تشمل تركيز المحفز (CC) ونسبة الميثانول (MR) وزمن التحويل (TT) ودرجة حرارة التفاعل (RT). تم تحليل تفاعلات التحويل JCO بالإضافة إلى تأثير معلمات التفاعل على محصول الديزل الحيوي Jatropha (JBY). تمت مطابقة كفاية النتائج التجريبية من خلال اختبارات التحقق المتسلسلة، ونتيجة لذلك، لوحظ متوسط 96.2 ٪ JMY في الظروف البارامترية المثلى، CC من 3wt. ٪، TT من 120 دقيقة، MR من 5 مول. و RT من 60 درجة مئوية عند سرعة تحريك ثابتة تبلغ 300 دورة في الدقيقة. نتج متوسط JMY بنسبة 87.6 ٪ من محفز A.granosa CaO أثناء دراسات إعادة التدوير وإعادة الاستخدام حتى دورة إعادة الاستخدام الثالثة.

Abstract Due to global warming, extreme hydroclimatic events (e.g., floods) are expected to happen more frequently and last longer. This study investigated such an extreme flood in the transboundary Teesta River that occurred in October 2021. We attempted to quantify the event's impact using data from time series flood levels, precipitation-related satellite images, and two-dimensional hydromorphological modeling. We found it challenging for people to cope with such a hazardous event since the depth of the flooding increased 6.98-fold in just 24 h. Our simulation results indicate that a sand-filled sediment measuring 0.27 m thick covered more than 33% cropland, and the velocity increased by almost 2.5 times. 136,000 individuals were marooned in the water. Compared to previous flooding events in its basin, which occurred in India and Bangladesh, the river appears to have some natural shock absorption features, i.e., a wide braided plain. We propose impact-based forecasting with a proactive early response as a valuable tool for managing such extreme events.

AbstractSustainable urban development is a key compoment in the United Nation’s Sustainable Development Goals. Monitoring urbanization is critical for planners, governments and non-governmental organizations, and scientists to design policies that maximize the use of natural resources and accommodate development while reducing environmental effects. This research aims to analyze how urbanization patterns have changed in the largely unknown least developed regions of Bangladesh. Multispectral satellite imageries over 30 years (1991 to 2021) were used to analyze the urbanization pattern of Jamapur district. Utilizing object-based image classification and on-field validation for seven Land Use and Land Cover classes, it was found that built-up area expanded by 748.92% during the past three decades while depleting bare soil (− 97.65%), deep waterbody (− 79.33%), shallow waterbody (− 8.46%), light vegetation (− 14.28%) and agricultural land (− 26.33%).. Because of increased in built-ups, the land surface temperatures (LST) were also increased over the study period (the minimun recorded LST were 12.84 °C, 15.89 °C, 15.8 °C and 17 °C while the maximun LST were 17.93 °C, 23.7 °C, 23.79 °C and 26.73 °C for the year of 1991, 2001, 2013 and 2021 respectively). This study will act as a baseline for future studies It be insightful to urban planners and policymakers in developing countries regarding urban sustainability and minimizing urban risks and hazards in the least developed districts.