bluuebunny/crossref_metadata_2025 huggingface dataset:
Routine Histopathological Analysis of the Synovium in Patients with Primary Total Knee Arthroplasty
Authors: Utkan Ali , Caliskan Emrah , Gencer Batuhan , Ozkurt Bulent
Published: May 2020

Although there are numerous studies about routine histopathological analysis during arthroplasty surgeries, most of them showed that new diagnoses have rarely been obtained as a result. The aim of this study was to evaluate the efficacy of routine pathological analyses of synovia resected during primary total knee arthroplasty in patients with osteoarthritis and its relevance in the treatment process. Of the 47 included patients who were followed up prospectively, 26 patients had clinical and histopathological concordant diagnoses and 21 patients had discrepant diagnoses. Oxford knee score and visual analogue score were performed for all the patients. Kallgren-Lawrence score was used for radiological analyses. The Mann-Whitney U test was used to examine the differences between the abnormally distributed variables. Mean age was 65.9 ± 4.3 years (range, 50–89 years) and mean follow-up time was 19 ± 7.8 months (range, 6–39 months). Grade IV gonarthrosis was found to be statistically lower in the discrepant group (p = 0.046). The mean preoperative Oxford knee score was 16.8 ± 2.3 (range, 2–23) and the mean postoperative Oxford knee score was 44.6 ± 1.8 (range, 27–48; p = 0.016). Postoperative Oxford knee scores and VAS were significantly increased in both the concordant and discrepant groups (p = 0.026 and p = 0.035, p = 0.019 and p = 0.039, respectively). Resection and histopathologic analyses of the hypertrophied and inflamed synovium encountered during primary arthroplasty procedure should be performed. This examination not only could provide crucial information that may influence the postoperative follow-up guidelines but also could help us to expand our knowledge and awareness of rare diseases that might yield osteoarthritis. The level of evidence for the study is level II.
Efficacy of Arthroscopic Arthrolysis in the Treatment of Arthrofibrosis: A Systematic Review
Authors: Cohen Jordan S. , Gu Alex , Kapani Nisha , Asadourian Paul A. , Stake Seth , Quan Theodore , Malahias Michael A. , Sculco Peter K.
Published: May 2020

Stiffness after total knee arthroplasty (TKA) remains a clinical challenge for health care professionals. Historically, arthroscopic arthrolysis is a treatment modality that has been reserved for patients that have failed other conservative modalities, including manipulation under anesthesia. However, a systematic review of the literature evaluating the clinical efficacy and complications of arthroscopic arthrolysis for stiffness after TKA has not been performed. A systematic review of medical databases (PubMed, EMBASE, Cochrane Library) was undertaken for articles published from January 1980 to October 2018. A descriptive and critical analysis of the results was performed. From 1,326 studies, 7 studies met the inclusion criteria for this study. A total of 160 patients who underwent arthroscopic arthrolysis for arthrofibrosis following TKA were included for analysis. The quality of the evidence for the included studies ranged between moderate and high. Overall, patients had significant increased range of motion and flexion by 32.5 and 26.7 degrees, respectively following arthroscopic arthrolysis. Functional outcome scores also significantly improved for patients who underwent arthroscopic arthrolysis after TKA. Arthroscopic arthrolysis is an efficacious modality for treatment of stiffness following TKA. The greatest benefit is seen among patients that present with significant loss of flexion. Arthroscopic arthrolysis should be reserved for patients that have previously failed more conservative modalities.
Single-Cut Single-Screw Capitate-Shortening Osteotomy for Kienbock's Disease
Authors: Bain Gregory I. , Krishna Sathya Vamsi , MacLean Simon Bruce Murdoch , Agrawal Parth
Published: May 2020

Background Kienbock's disease, in spite of an uncertain natural history, is known to cause lunate compromise, leading to central column collapse, carpal instability, and degenerative arthritis of the wrist. Joint leveling procedures are performed in the early stages of Kienbock's disease to “unload” the lunate. Capitate shortening is the preferred procedure in Kienbock's patients with positive ulnar variance.

Description of Technique We describe the rationale and a simplified technique of capitate shortening in early Kienbock's disease. This is a single-cut osteotomy with single-screw stabilization.

Patients and Methods We have performed this technique in three cases. We present a case of a 26-year-old male who presented with a 1-year history of pain in his right wrist. Radiology performed demonstrated lunate sclerosis. Diagnostic arthroscopy revealed healthy articular surfaces. Single osteotomy capitate shortening was performed with an oscillating saw and fixed with a single cannulated compression screw. A shortening of 1.5mm was obtained with this technique.

Results At 1- to 2-year follow-up, all three patients had considerable pain relief but did not have a complete resolution of pain. There was a significant improvement in function and grip strength. There have been no cases with infection, nonunion, avascular necrosis or a need for a salvage procedure.

Conclusion The simplified technique of capitate shortening is easy to perform, less traumatic to the capitate vascularity, and leads to good short-term functional results.
Radar points the way to detecting cosmic neutrinos
Authors: Wilson R. Mark
Published: May 2020

A laboratory experiment at SLAC offers the first observations of radio-wave reflections from ionization trails of particle showers in a transparent solid.
Localized electric field manipulates a nuclear spin
Authors: Berkowitz Rachel
Published: May 2020

The atom-level control could provide the precision required for some quantum computing applications.
Spongy hydrogels clean textured paintings
Authors: Miller Johanna L.
Published: May 2020

Washing away the dirt from an artistic masterpiece is especially tricky when the surface is not flat. New materials can help.
Thermal extremes in regulated river systems under climate change: an application to the southeastern U.S. rivers
Authors: Cheng Yifan , Voisin Nathalie , Yearsley John R , Nijssen Bart
Published: May 2020

High river temperatures, or ‘thermal extremes’, can cause fish mortality and thermoelectric powerplant derating. Under climate change, projected higher air temperature and stronger surface energy fluxes will lead to increased water temperatures, exacerbating thermal extremes. However, cold hypolimnetic releases from thermally stratified reservoirs can depress tailwater temperatures and therefore alleviate thermal extremes. Thermal extremes are more harmful when they coincide with low flows, which we refer to as ‘hydrologic hot-dry events’. To assess multi-sectoral impacts of climate change over large regions, we evaluate thermal events according to three impact attributes: duration (D), intensity (I), and severity (S). We apply an established model framework to simulate streamflow and stream temperature over the southeastern US regulated river system. We quantify climate change impacts (by the 2080s under RCP8.5) by comparing historical and future periods and quantify regulation impacts by comparing unregulated and regulated model setups. We find that climate change will exacerbate thermal extremes (all three metrics) in both unregulated and regulated model setups, albeit less in the regulated setup. Thermal mitigation from reservoir regulation will be stronger under climate change, decreasing the three metrics compared to the unregulated case. Even so, thermal extremes in the regulated setup will still be more severe under climate change, and only 12.2%, 19.7%, and 26.0% of D, I, and S can be mitigated by reservoirs. Despite stronger reservoir stratification, the number of regulated river segments that experience simultaneous high temperature and low flow events (hydrologic hot-dry events) will increase by 21.4% by the 2080s under RCP8.5. These events will have a median annual duration of 10.3 day/year, over 10 times the historical value.
Geopolymer production for conservation-restoration using Sicilian raw materials: feasibility studies
Authors: Barone G , Caggiani M C , Coccato A , Finocchiaro C , Fugazzotto M , Lanzafame G , Occhipinti R , Stroscio A , Mazzoleni P
Published: May 2020

In the last decades, particular attention has been aimed to innovative materials class with high-tech features to apply in conservation-restoration of Cultural Heritage, ensuring both aesthetic compatibility and adequate properties with regards to the original rock substrate. AGM for CuHe project aims to valorise Sicilian raw materials, natural and industrial by-products, for the development of alkali-activated materials, as geopolymers. These materials are produced by the activation of an aluminosilicate precursors in alkaline environment. Volcanic raw materials (volcanic ash, volcanic paleo-soils and pumice) and ceramic industrial waste were mixed with an alkaline solution and cured at room temperature. In some cases, small quantities of metakaolin were added to the mixture to increase the reactivity of the precursors. In order to obtain the geopolymeric reaction, the precursors need to be fully characterized. A similar approach is also applied to the synthesized geopolymers in order to understand its behaviour in relation to the original building materials. Therefore, a multi-analytical approach is proposed: chemical and mineralogical studies (XRF and XRD), combined with spectroscopic (FT-IR) and morphological (SEM and μCT) analyses. These preliminary results confirm the feasibility of this eco-friendly class of materials using the proposed local raw materials.
Silver fir characterized by micro-imaging NMR and FTIR spectroscopy
Authors: Longo S , Capuani S , Corsaro C , Fazio E
Published: May 2020

Nuclear Magnetic Resonance micro-imaging (μMRI) approach with multiparametric measurement and FTIR spectroscopy was adopted to investigate silver fir. In particular, we investigated weakly interacting and bound water, detected by NMR and FTIR techniques, hypothesizing a water interaction with the main structures of the wood. For instance, by means of NMR analyses, we obtain information about the principal wood morphological/structural modifications, which are associated with humification processes, reflected in the changes of aromatic C-H and C-O vibration modes shown by FTIR. Thus, the combined use of NMR and FTIR allows characterizing the mobility of water with respect to lignin and cellulose features, which can serve as a benchmark for wood degradation conditions.
New perspectives for the green economy in Sicily
Authors: Parisi F , Sabatino G , Marciano G , Mottese A , Nania G , Leonetti F , Sfameni S , Bella M Di , Mazzoleni P , Barone G , Tripodo A , Drommi D , Magazu S
Published: May 2020

Geopolymers are synthetic materials, which attract increasing interest because they represent a supplementary cementitious material as an alternative to Portland cement. Geopolymers are considered as environmentally friendly materials, due to the low processing temperature and the absence of CO2 gas emissions. These ecological features, linked to their technical properties, such as high strength, high acid resistance, and/or high-temperature resistance, make them very innovative technological materials. In addition, geopolymers show good performance if realized by the utilization of secondary raw materials (industrial wastes like fly ash or slag), thus improving strong interest in such technology from countries with growing industrialization. Here, in order to reduce global impacts and to stimulate the Sicilian green economy, we provide the evaluation of the Life Cycle Assessment (LCA) through the employ of local raw materials to produce geopolymers in Sicily. To reach this aim, geopolymers have been produced in collaboration with a Sicilian cement industry, through the use of local raw materials (furnace blast slag from Sicilian steelworks and Calabrian kaolinite) and the construction of a pilot plant. The obtained results show, for different scenarios, a considerable reduction of both CO2 emissions and energy consumption, but also a general improvement of the environmental indicators.
Synthesis and characterization of silver nanoparticles as a potential sensor for volatile organosulfides for visual detection of postharvest storage in garlic
Authors: Motol R K C , Espineli C A , Tapit C M V , Tiangco C E
Published: May 2020

Garlic, one of the most popular spices used in manufacturing many food products, is subjected to fungal and bacterial diseases resulting to substantial losses in quantity and quality. Specific detection tools for garlic spoilage will be an asset in relieving these losses during postharvest storage. In this study, stable yellow-colored silver nanoparticle colloidal solution was studied as a potential sensor for volatile organosulfides in garlic. The silver nanoparticles (AgNPs) were synthesized by chemical reduction method where silver nitrate was taken as metal precursor, sodium borohydride as reducing agent, and polyethylene glycol as stabilizing agent. The silver nanoparticles were characterized by UV-Vis Spectroscopy and Dynamic Light Scattering (DLS). The spectral analysis revealed the formation of silver nanoparticles by exhibiting the typical surface plasmon absorption peak at around 395 nm. The DLS results show two populations of AgNPs with particle sizes of 3 nm and 50 nm. The volume ratio of sodium sulfite to be added in the silver nanoparticle and the reaction time was also determined. Synthesized AgNPs could detect sodium sulfite at 0.52 to 50 µM concentration range. This simple method indicated the potential of silver nanoparticles as a powerful detection tool for volatile organosulfides in garlic.
Photocatalytic degradation of Atrazine herbicide using nano-Hydroxyapatite from Cow Bone synthesized via Simulated Body Fluid
Authors: Vicente Rubi Rugi , Roque Erison , Dela Rosa Francis , Martin Estoque Rey , Olvido Gerald , Jane Perey Patricia , Teresa Jabin Sta. , Anne Tesalona May
Published: May 2020

The excessive usage of herbicide in agricultural industry has known to cause unexpected side effects both on human and environment. This present study investigates the viability of using nano-Hydroxyapatite as a catalyst in the photodegradation of the herbicide Atrazine. Nano-hydroxyapatite (nHAp) was synthesized using cow bone as the calcium source via simulated body fluid (SBF). Physical and morphological characterization was done using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The SEM analysis results indicates the formation of globular precipitated nHAp with 22 to 114 nm particle diameter size. The FTIR and XRD results confirmed the presence of functional groups and crystal structure associated to presence of hydroxyapatite. The photodegradation of the Atrazine herbicide results showed a steady increase in efficiency with the increasing amount of catalyst and UV exposure time. The highest degradation efficiency of 52% was achieved with 0.7 g nHAp for 2.5 hrs exposure. This study showed that Atrazine herbicide can be effectively treated with the proposed method to reduce the environmental impact of the herbicide by converting it into potentially less dangerous by-products that can be less harmful.
Mesoporous silica nanoparticles as vehicles for drug delivery
Authors: Adristya I M , Suryaningtyas A D , Wijaya J , Pangestu F C , Hartono S B , Soewignyo L H , Irawaty W
Published: May 2020

Silica-based materials such as mesoporous silica nanoparticle MCM-41 and hollow mesoporous silica have been synthesized at room temperature. Several characterization techniques such as N2 adsorption-desorption analysis, SEM and FTIR have been employed to assess the formation of the nanoparticles. Rifampicin, commonly used in tuberculosis treatment, was selected as the target drug to assess the ability of the two nanoparticles to host this antibiotic. Following the loading of rifampicin on the particle surface, the dissolution behaviour of rifampicin in a media was investigated. Surface characterizations show HMS exhibits higher surface area as well as pore size and volume compared to MCM-41. However, rifampicin was not attached on the latter particles until it was modified with APTES. HMS particles store more rifampicin molecules on the particle surface than the modified MCM-41. The in-vitro drug release was investigated with buffer phosphate (pH=7.4) and the results shown that the rifampicin-loaded HMS particles were capable of releasing 18% rifampicin content after 77 h. Further investigation was necessary to support the promising application of mesoporous silica nanoparticles for pulmonary drug delivery.
The effect of uric acid in the detection of calcium stones in urine through turbidimetry method
Authors: Bacani P A , Maglaqui J A , Tadeo A A , Quinto E
Published: May 2020

An increase of 10-12 percent in the number of Filipinos afflicted with kidney or renal disease is recorded per year according to the National Kidney Transplant Institute. Thus, the diagnosis of calcium stone formation, or urinalysis, in urine is a significant contribution to the medical industry. This study presents a diagnostic LED photoresistor sensor that can selectively determine calcium stones in the presence of uric acid. The LED photoresistor sensor, with Hantek data logger, was used to determine the concentration of Ca (II) in the urine sample. The features of the sensor system have a signal stability of 0.0596 % relative standard deviation (RSD) and repeatability of 10.35% RSD when 80 ppm of standard Ca (II) is compared to a blank in the presence of 60 ppm of uric acid. The calcium sensor photoresistor shows a calibration curve of y=0.0001x-0.0023 with a limit of detection of 46.84 ppm. The linear coefficient of the calibration curve, R2 is 0.9902.
The Optimal Condition on the Growth of Green Haematococcus Pluvialis as one of the Future Natural Resources
Authors: Retti Witono Judy , Gunadi Alvin , Santoso Herry , Miryanti Arry , Kumalaputri Angela J.
Published: May 2020

In the developing world nowadays, the need of antioxidants as counteracting free radicals becomes more and more. Astaxanthin is a carotenoid pigment with high antioxidant content. It can be obtained from natural sources or chemical synthesis. Haematococcus pluvialis is one of natural sources of astaxanthin which accumulates large amounts of astaxanthin under stressful condition. The growth of H. pluvialis in the green phase determines the amount of astaxanthin that can produced. It is influenced by various conditions such as amount and type of growing medium, light intensity, pH of medium, temperature, and initial inoculum concentration. The goal of this research is to obtain the optimum condition on the growth of H. pluvialis at the green stage using the experimental design i.e. Central Composite Design (CCD). The variables observed were the effect of the initial inoculum concentration (25-35% -v/v), the concentration of nutrients (1-2 mL/L liquid water), and the types of growth medium (Walne’s and BG-11). Before the experiment, H. pluvialis was cultured until its optical density (OD = 1 – 1.2). The responses observed were the cell density based on optical density (OD) using a spectrophotometer and cell number counted by using haemacytometer every day during 5 days. The results were examined using the Design Expert 7.0. It showed that the optimal growth conditions of H. pluvialis cells was in BG-11 medium with initial inoculum concentration and the number of nutrients were 37, 07% and 1.5 mL/L respectively. The highest cell number was found 23, 75 x 106 cells / mL in the 3rd day. Whereas by using Walne media, the optimum condition was obtained at the initial inoculum concentration and the amount of nutrients were 35% and 2 mL respectively. And the highest cell density number obtained was 17, 5 x 106 cells / mL on the 3rd day.
Performance of Stored Electrolyzed Seawater for Disinfection of Pseudomonas aeruginosa
Authors: Ferrer Michelle Joan C. , Lim Ryan Kenneth L. , Cue Russell Dillon A. , Beltran Arnel B. , Damalerio Regina G. , Uba Marigold O.
Published: May 2020

Electrolysis of seawater has the ability to produce free chlorine (FC), sodium hypochlorite (NaClO), hypochlorous acid (HOCl) and other oxidants which enable it to kill pathogens making it a viable disinfectant. However, the stability of this disinfectant is somewhat unpredictable during storage. This study determined the effects of storage time on the stability of electrolyzed seawater (ESW) in terms of its physicochemical properties, specifically pH, oxidation-reduction potential (ORP), and free chlorine concentration (FCC) for 83 days and evaluated its disinfection performance on Pseudomonas aeruginosa. The effect of dilution in the disinfection was also investigated at ESW to water ratio of 1:0, 1:1, and 3:6. Pre-filtered seawater was electrolyzed at 1.5 A for 20 minutes using platinum-coated titanium mesh electrodes. The ESW was transferred to opaque high-density polyethylene (HDPE) bottles stored at ambient temperature without direct exposure to sunlight. The physicochemical properties of ESW at different storage times were determined, and its disinfection capability against P. aeruginosa was evaluated. This study has made use of two trials for the physicochemical test due to two different batches of seawater were taken. pH was found to increase over time, having a range of 6.32 to 7.705. The ORP and FCC, on the other hand, decreased over time. In accordance with the literature found, the pH ranges show that hypochlorous acid is the main driver of disinfection. Complete disinfection of ESW at 3:6 dilution was observed until 48 days of storage, while the 1:0 dilution was until 83 days and 1:1 dilution was until 51 days. FC decay (k=-0.1449 day−1 and k=-0.0544 day−1) was determined using Chick’s Law. Even at different dilution levels, ESW still proved its bactericidal efficacy in this research.
Mechanism and kinetic model for glycerolysis of shellac
Authors: Hartanto D T , Rochmadi  , Budhijanto
Published: May 2020

Shellac is a resin which is secreted from Kerria lacca, that can be utilized for coating and polyester. This material is brittle and stiff, hence modification of shellac is needed. One alternative to change its properties is by modification with glycerol. The purpose of this study is to investigate reaction between shellac and glycerol in the absence of catalyst. Moreover, in this research, the effect of hydroxyl position of glycerol is studied. In this present work, reaction was carried out for 2 hours and samples were taken every 15-30 minutes for analyzing the residual glycerol. Residual glycerol was analyzed using the periodic acid method. The reaction was carried out at various temperatures (160°C, 170°C, 180°C and 200°C). The results showed that glycerolysis reaction could be undertaken between 160°C - 180°C. In addition, the effect of ratio between glycerol and shellac was also investigated. In this study glycerol:shellac ratios were = 1:1; 1.5:1; and 2:1. The average relative error between experimental data and model in various temperature is 8.79%, while in the various ratio of glycerol and shellac is 8.26%. It showed that the kinetics model can describe well the reaction between glycerol and shellac.
Preliminary Modified Biodiesel Production by Coupling Reactive distillation with a Steam Reformer via Aspen Plus®
Authors: Treeyawetchakul C
Published: May 2020

The conventional two-step biodiesel production process (esterification step followed by a transesterification step) from crude palm oil (CPO) has been carried out for years. However, the production cost from this process still cannot compete with fossil diesel. To reduce the capital and operating cost, the process should be modified by replacing both the reactor and the distillation column of the transesterification step with reactive distillation. In addition, glycerol, a by-product of the process, could convert to H2, a high value-added product, via a steam reformer to help reduce the biodiesel production cost. The energetic and economic possibility of the modified biodiesel production process was studied and simulated via Aspen Plus software in this work. The biodiesel production capacity from CPO (15 wt.% FFA) of ca.1, 000 kghr−1 employed from previous researches was considerably basis. The conventional and modified processes in terms of process utility and biodiesel production cost were compared. The simulation results show that the biodiesel cost from the modified process decreased by 40.85% compared to the conventional ones, because of the reduction of capital cost and selling H2. The result preliminarily confirmed that the modified biodiesel process was promising due to energy saving and economic concern.
Optimization of the production of a complete fertilizer formulation by batch impregnation using clinoptilolite zeolite as carrier
Authors: Catli N B J , Migo V P , Alfafara C G , Maguyon-Detras M C , Brutas C C P
Published: May 2020

Fertilizer inefficiencies caused by uncontrolled and rapid nutrient release pose serious environmental threats and economic losses. Adsorption of nutrients in carriers such as clinoptilolite zeolite (CZ) has been proven to be effective in minimizing environmental pollution and improving the duration of nutrient availability in soil. In this study, a complete fertilizer was formulated via the batch impregnation of the combination of nutrient sources, such as urea, calcium hydroxyapatite (CaHAp), and muriate of potash (MoP), in CZ carrier in a 1:1 ratio. Carrier pre-treatment was done by washing CZ with deionized water and ethanol, followed by calcination at 600 °C for 4 hours. The process has 86.92% recovery and increased the cation exchange capacity (CEC) of the carrier from 41.30 cmol(+)/kg soil to 47.7630 cmol(+)/kg soil. The effect of mixture factors (% Urea : % CaHAp : % MoP ratio) and process factors (mixing time and sonication time) on the total nitrogen (N), phosphorus (P), and potassium (K) content was investigated using an Optimal (Combined Mixture) Experimental Design. Statistical analysis showed the direct effect of the mixture factors and the insignificant effect of the process factors on the said responses. The optimum conditions obtained via numerical optimization is as follows: (1) 50 : 23.99 : 14.61 : 11.39 (% PCZ : % Urea : % CaHAp : % MoP) ratio, (2) mixing time of 158.57 minutes, and (3) sonication time of 30 minutes. This resulted to a fertilizer with a total N, P, and K content of 4.65 % 2.76 %, and 5.42 %, respectively. Moreover, it has about 1.96 % bound N, 0.28 % bound P, and 2.93 % bound K due to a successful adsorption process. The adsorption process has a high fertilizer yield of 96.49 %. DLS analysis revealed that the optimized product has an average particle size of 4105.8 nm; thus, it cannot be characterized as a nanofertilizer. Cost analysis showed that the formulated complete fertilizer is priced at Php 465.82 per kilogram, which is more expensive than the 14-14-14 conventional fertilizer due to higher cost of production. However, the possible slow/controlled release property of the NPK-PCZ fertilizer could offset the high price due to longer availability of nutrients in soil. As such, this could mean lower rate of fertilizer application thus allowing to save up in resources and manpower.
Parameters study on the production of isoamyl acetate via milli-reactor in a solvent-free system
Authors: Mansor Nuraini , Singaravelan Rajaviknesswaran , Rizal Abd Shukor Syamsul
Published: May 2020

Isoamyl acetate is an aromatic ester that has a similar smell to banana. This ester is high in demand for various industries application, especially in the flavour and fragrance sectors. This research aims to investigate the effects of synthesis parameters on the production of isoamyl acetate in a milli-reactor. Non-catalyzed reaction was performed by reacting isoamyl alcohol with acetic anhydride without further dilution. The flow rate of 40 to 80µL/min, reaction temperature of 20 to 50°C, and acid-alcohol molar ratio of 0.5 to 2.0 were chosen as the reaction parameters. All samples were analyzed through gas chromatography with flame-ionization detection (GC-FID). The results revealed that the highest production of isoamyl acetate was obtained at the flow rate of 60µL/min and temperature of 50°C with the acid-molar ratio of 0.5. In conclusion, these synthesis parameters significantly influences the non-catalyzed esterification reaction of isoamyl acetate production in a milli-reactor.
Rate-based simulation study of boric acid promoted potassium carbonate capture system
Authors: Ayittey Foster K , Saptoro Agus , Kumar Perumal , Wong Mee K
Published: May 2020

This study presents parametric analysis and process modification on a post-combustion carbon dioxide (CO2) capture system using boric acid promoted potassium carbonate (K2CO3) solution. The model was simulated in Aspen Plus® V10 and ELECNRTL property package was employed. Un-promoted K2CO3 system was adopted as a base case study and its simulation was validated using literature data. The K2CO3 concentration in the lean solvent makeup was then varied from 25 wt% to 40 wt% to examine the effects of lean solvent concentration on key operating variables such as stripper reboiler duty, stripper condenser duty and CO2 capture rate. A 2 wt%, 4 wt% and 6 wt% aqueous boric acid solutions were then added as promoter to the hot K2CO3 solvent and the simulation results indicated that capture rate efficiency can be enhanced by 0.7%, 0.9% and 1.2% respectively. Energy saving process modification was also carried out to the stripper column. Compared to the conventional unmodified H3BO3/K2CO3 system, the modified promoted system is able to achieve 21.09% savings in reboiler duty.
Multi-Objective Optimization for Combined Heat Power Operations considering Flexibility, Costs and Environmental Emissions
Authors: Wei Jen Lok , Yin Ng Lik , Andiappan Viknesh
Published: May 2020

Optimal operation of a combined heat and power (CHP) system proves to be a challenge. This is because CHP systems could be operated in several alternative configurations. In fact, each technology may have different heat and electricity outputs, costs, emissions and flexibilities. To address such challenge, operational optimization must be considered. In this paper, a mathematical optimization model was developed to optimise cost, carbon dioxide emissions and flexibility for a CHP system operation to meet increased energy production requirements. The developed model employs multi-objective optimization to determine a trade-off between costs, carbon dioxide emissions and flexibility. To demonstrate the proposed approach, a multi-fuel CHP case study was solved. Results indicate that a trade-off CHP configuration that achieves the best possible balance between costs, emissions and flexibility was determined.
Optimization of methanol production via CO2 hydrogenation: comparison of sampling techniques for process modeling
Authors: Borisut P , Nuchitprasittichai A
Published: May 2020

This paper compares performances of three different sampling techniques in representing nonlinear response surface for optimization problem, with five decision variables. Three studied sampling techniques are Central Composite Design (CCD), Box – Behnken Design (BBD) and Latin Hypercube Sampling ( LHS). Simulation – based optimization of methanol production via CO2 hydrogenation process was used as a case study. The objective of this optimization problem is to minimize the methanol production cost. The nonlinear model ( the objective function) represents the relationship between operating conditions and methanol production cost. The results show that the response surface of this case study is trend to be the third order model ( with R – squared value greater than 0.97) for all sampling techniques. BBD is the most suitable sampling technique in this study, resulting in the percent error less than 1.2. The LHS shows comparable performance with BBD if it has suitable number of sample points.
Impact of biomass upgrading via hydrothermal treatment on slagging and fouling during cofiring with coal
Authors: Yan Mi , Ar Rahim Dicka , Susanto Herri , Dennie Agustin Pohan Rahmad , Hantoko Dwi
Published: May 2020

Palm oil empty fruit bunch (EFB) is a by-product produced during palm oil processing. In South East Asian countries, EFB is abundant and can be utilized as a renewable energy source. Cofiring of EFB with coal can be beneficial for preserving coal and reducing CO2 emission. However, EFB has some weaknesses in its properties such as; low bulk density, high moisture content, high alkaline contents, etc. Moreover, high amount of silicon and potassium in EFB tend to increase ash agglomeration which causes slagging and fouling in the equipment. In this study, hydrothermal treatment (HT) was employed to improve the physicochemical properties of the EFB by turning into biochar. Biochars are obtained after EFB is treated hydrothermally at a temperature range of 200-300 oC for 60 minutes were characterized for their proximate and ultimate compositions, mineral composition, calorific values, and ash fusion temperature. The analyses showed that fixed carbon increased while volatile matter decreased after HT. These changes were more prominent with increasing reaction temperature. The calorific values of EFB increased from 19.05 MJ/kg to 29.31 MJ/kg after HT at 300 oC. The biochar was then mixed with coal at different ratios (1:1, 1:2, and 2:1) for cofiring. The results showed that the energy densification increased with increasing reaction temperature. XRF results showed that the contents of Na, K and Si in EFB decreased after HT, resulting in the increased ash melting temperature. Consequently, the fouling and agglomeration potential could be reduced. The optimum ratio for cofiring between biochar and coal was found to be 2:1, as the fouling and slagging indices were lowest. It can be concluded that HT is a promising method for upgrading EFB as a feedstock for cofiring with coal.
Effect of glucose concentration and cultivation days on Chlorella vulgaris growth via immobilization technique for biodiesel production
Authors: Abu Sepian N R , Mat Yasin N H , Zainol N
Published: May 2020

Immobilization technique had been utilized to simplify the separation process of microalgae biomass for biodiesel production in the present study. The optimization using response surface methodology (RSM) through central composite design (CCD) approach had been applied to maximize the number of cells growth and minimized the cells loss of Chlorella vulgaris cells via immobilization technique. Two effects were optimized by CCD consisting of glucose concentration and cultivation days. The glucose concentration at 23.99 g/L and 7.96 days of cultivation time were found to be the optimum conditions for the maximum number of cells growth (3.30 × 109 cells/mL) and a minimum number of cells lost (1.07 × 104 cells/mL). The optimization using CCD had increased the lipid to 51.6 % and the result of fatty acid methyl ester (FAME) profile is similar to non-bearing oil crop. The findings had revealed the potential of immobilized microalgae biomass as an alternative feedstock for biodiesel production. Moreover, this study had reported optimum conditions for an efficient recovery process via immobilization technique using mixed matrices.
Kinetic analysis of co-pyrolysis of biomass/sorbent mixtures at different ratios
Authors: Ariffen A R , Yusoff N
Published: May 2020

Biomass is one of the most promising sources of renewable energy. Gasification of carbonaceous and lignocellulosic biomasses produces gases, which can be upgraded as a clean feedstock for power plants. However, control and optimization of industrial gasification is still a challenging task due to a lack of understanding in solid state reaction mechanisms. This work attempts to improve kinetic modelling of a gasification process through analyses of four locally available biomasses, namely, oil palm trunk, fronds, empty fruit bunches, and coconut fibre. The biomasses were mixed with sorbents to enhance the pyrolysis and gasification reaction in a thermogravimetric analyser. In addition to common sorbents such as oxides of magnesium and calcium, two other sorbents, namely, rice husk and eggshell (a source of calcium carbonate) were blended at different ratios of biomasses to investigate their behaviour under pyrolytic decomposition conditions. Activation energies of the mixtures were obtained with the Reaction Rate Constant Model (RRCM). It was found that the mixtures had higher activation energies as compared to pure biomasses. For example, oil palm trunk without sorbent and with 50 wt% calcium oxide had activation energies of 26.87 and 46.83 kJ/mol, respectively. Majority of the sorbents also increased the thermal stability of the biomasses by increasing the mixtures’ resistance to weight loss under high temperature. However, rice husk reduced the mixtures’ thermal stability when compared with pure biomasses as evident in the oil palm trunk case when the mixture became 6.2% less thermally stable.
A comparison of the acid mine drainage (AMD) neutralization potential of low grade nickel laterite and other alkaline-generating materials
Authors: Turingan C. , Singson G. , Melchor B. , Alorro R. , Beltran A. , Orbecido A.
Published: May 2020

Acid mine drainage (AMD) is a serious environmental problem caused by the weathering of sulfur-rich minerals found in mine sites, typically pyrite. Passive treatment methods have been extensively studied exploring various materials and treatment systems. Limestone is typically used as neutralizing media through open channels or anoxic limestone drains. However, the armouring that occurs when heavy metals precipitate on the surface restricts the lifespan of limestone treatment systems to 15-20 years. Goethite has been characterized to be a good adsorbent of heavy metals found in wastewater. It is abundant in a layer of nickel laterite deposit which are considered mine wastes due to the low amount of nickel present. This study investigates the performance of locally available nickel laterite ore rock, limestone, fly ash, and cement waste as media for AMD neutralization. The treatment efficiency are evaluated based on the physiochemical properties of the AMD, namely: pH, redox potential (ORP), conductivity, total dissolved solids (TDS), and dissolved oxygen (DO).
Effect of Coolant Temperature and Stirring Rate in the Separation of Oil from Bilge Water using a Stirred Freeze Crystallizer
Authors: Mustapha S. N. A. , Amran N. A. , Samsuri S.
Published: May 2020

Each year, marine activities has contributed to nearly half of the discharged oil into the oceans, where 10% of it were dumped bilge oil. The tankers release oily and chemical residue, causing pollution to the marine environment due to excessive contamination of bilge water. Therefore, all marine ships over 400 tons are required to install an oil-water separator (OWS) system on board to limit the discharge of oil into the oceans. However, the current OWS technologies such as gravity and centrifugation method have difficulties to comply with the oil/grease discharge standard of 15 mg/L set by Malaysia’s Department of Environment (DOE). This paper aims to introduce progressive freezing (PF) process as a new OWS method where it separates two liquid compounds based on their freezing point difference. One with higher freezing point will solidify first while another one will remain as liquid. In this study, the effect of coolant temperature and stirring rate towards oil/grease values were investigated. It was found that the highest efficiency of the PF process was obtained at stirring rate of 200 rpm and coolant temperature of -6°C. In addition, the best oil/grease value obtained was found to be lower than the discharge standard permitted by the Department of Environment (DOE), Malaysia.
Effect of Biocover Thickness on Methane Oxidation Rate of Landfill Gas Emission from Municipal Solid Waste Landfill in Tropical Climate Region
Authors: Yusnan  , Razi F. , Munawar E.
Published: May 2020

The landfilling of municipal solid waste (MSW) in developing countries mostly is carried out by means of open dumping or control landfills. The degradation of organic compounds of MSW inside the landfill will produce the landfill gas, where the main component is methane (CH4) and carbon dioxide (CO2) are categorized as the greenhouse gas (GHG). These gases if not managed properly will escape and increase the GHG accumulation in the atmosphere. There is many methods has been established and apply to reduce landfill gas emission, but mostly required high investment so not affordable for developing countries. Method that might be applied to reduce GHG emissions from landfill in developing countries is utilization the microorganism to oxidizing CH4 commonly called biocover. The purpose of the study was to analyze the effect of biocover thickness on the oxidation efficiency of CH4 from landfill gas in tropical countries. The concentration CH4 in landfill gas throughout landfill simulator reactor (LSR) covered by 20-60 cm of thick the biocover was measured daily by using the gas analyzer (Sewerin, Multitec 540). The LSR was made of acrylic pipe with a diameter of 25 cm and height of 100 cm. The landfill gas was used has an initial concentration of CH4 approximately 30% and the moisture content of biocover used was maintained at 40%. The experimental results obtained shows the CH4 oxidation efficiency of biocover for 20 cm, 40 cm and 60 cm thick were 8.12%, 9.72% and 4.56%, respectively.
Total phenolic content and antioxidant activity of Pandanus amaryllifolius by soaking and microwave-assisted extraction
Authors: Asyikin Md Zaki Nurul , Abd Hashib Syafiza , Kalthum Ibrahim Ummi , Ani Narisa Ahmad Bakhtiar Putri
Published: May 2020

Many studies have reported on the limitation of conventional extraction methods. Therefore, this work aims to compare the effects of conventional soaking extraction and microwave-assisted extraction (MAE) on the total phenolic content (TPC) and antioxidant activity of Pandanus amaryllifolius leaves. For soaking method, the pandan leaves were soaked in various ethanol-water mixture (50, 75 and 100%) at different temperatures (40, 50, 60, 70°C) for 10 minutes. Meanwhile for MAE method, the pandan leaves were extracted in the same concentrations of ethanol-water and subjected to different microwave power level (100, 180, 300, 450, 600 and 850W) for 10 minutes. It was found that MAE resulted in higher yield of TPC (1.557 mg/g gallic acid equivalent) compared to conventional soaking method (0.979 mg/g gallic acid equivalent). MAE could remarkably retain bioactive total phenolic content and antioxidant activity and has huge potential and application in the food industry.
Estimating species concentration in CO2-loaded monoethanolamine using Raman spectroscopy
Authors: Syukri Na’im Bin Mohd Hanafiah Ahmad , Shah Maulud Abdulhalim
Published: May 2020

Operation of amine plant for CO2 removal had long been plagued with inefficiencies due to suboptimal operating parameter leading to losses in operational expenditure. Improving the system requires understanding into thermodynamics and kinetics of the process which can be made possible through having information on the qualitative and quantitative speciation in the alkanolamine system. In this work, potential of Raman spectroscopy as a monitoring tool for species concentration in CO2-loaded aqueous monoethanolamine (MEA) system was investigated. CO2 loading data from experimental work were used with Kent Eisenberg model to estimate species concentrations (dissolved CO2, Protonated amine, Bicarbonate, Carbonate, Carbamate and unreacted MEA). Each species concentration were fitted to experimentally-acquired Raman spectrum using Partial Least Square Regression (PLSR) technique to develop calibration model. Evaluation of regression plots, R2 and Root Mean Square Error (RMSE) shows good predictive accuracy compared to the thermodynamically-predicted species concentration.
Study of progressive freeze concentration and eutectic freeze crystallization technique for salt recovery
Authors: Mazli W N A , Samsuri S , Amran N A
Published: May 2020

In this industrial era, salt recovery from seawater has become an important issue from the environment perspective. Few freezing technologies have been proposed as capable way to separate the salt from the seawater because of the energy used in the previous technologies is higher. A study of Progressive Freeze Concentration (PFC) and Eutectic Freeze Concentration (EFC) method have been carrying out and further investigated on their performance in recovering the salt. For the PFC method, pure water crystallizes into crystal and the concentrate is left behind as in liquid form while for the EFC method, both ice crystals and salt crystallize at the same time when the initial concentration of water salt mixture is exactly the same as eutectic concentration. In EFC, salt sinks to the bottom while ice floats at the top of the crystallizer and both are separated by gravity separation. Effective partition constant and solute recovery are calculated to evaluate the efficiency of PFC and EFC. In this study, the PFC method has shown an effective partition constant of 0.28 and recovered solute of 0.88 g of sodium chloride per 1 g of initial sodium chloride while for EFC method, effective partition constant and solute recovery obtained are 0.59 and 0.66. Overall, both techniques are applicable for the seawater desalination process.
Study of raw and chemically treated Sansevieria ehrenbergii fibers for brake pad application
Authors: S Senthil Kumaran , Srinivasan Kathiravan , M Ponmariappan , S Yashwhanth , S Akshay , Hu Yuh-Chung
Published: May 2020

The replacement for synthetic fiber and other materials with natural fiber in the brake pad has become a key research area in many industries. Many production industries are always focused on natural fiber over synthetic fibers because of its advantage of biodegradability, less expensive, availability, and environment friendly. However, natural fibers cannot be used directly in composites because of its poor adhesion behavior between matrix and fiber and observe high water content in the fiber. Further, the excess water content in the inside fiber has been removed by using alkaline, benzoylation, and acetylation treatment. It has been achieved by the same chemical concentration but with different time duration. The Fourier-transform infrared spectroscopy (FT-IR) analysis revealed that the amount of cellulose content after chemical treatment was improved and decrease in other substances like hemicellulose, lignin, and wax content. X-Ray Diffraction (XRD) analysis study confirmed that the rise in the crystalline index (70.41 from 52.7) of alkali-treated SEFs at 30 min. The thermogravimetric analysis study has confirmed that the increase in the degradation temperature of Benzoyl-treated SEFs (387 °C) at 60 min when compared with untreated fiber (320 °C). The Scanning Electron Microscope (SEM) results have confirmed that the elimination of impurities from the fiber surface after chemical treatment. Further, the acetyl- treated fibers have shown that better hydrophobic properties than other treated fibers. In the above tests have been concluded that the chemically treated fibers, as one of the suitable materials for the development of the brake pad application.