An experimental investigation of microalgal dewatering efficiency of a belt filter system

Profitable large-scale production of biofuel from microalgae has not yet been demonstrated. A major bottleneck is high operational cost of microalgal harvesting. This is due to small cell size and dilute microalgal suspension. A belt filter system is preferred over other dewatering technologies as it has lower energy consumption. However, a microalgal feed concentration of 10 - 40 g dry wt. /L is required prior to dewatering on a belt filter system. The objective of this study was to investigate the microalgal dewatering efficiency of a belt filter system. A prototype belt filtration system designed for feed concentration of 50 g dry wt. /L was used for this investigation. A mixed laboratory culture of freshwater species dominated by three eukaryotic green microalgae (Chlorella vulgaris, Scenedesmus sp., and Kirchneriella sp.) was cultivated in wastewater effluent. Bench-scale gravity filtration tests were conducted to determine the filtration belt mesh needed for the prototype system. Based on the test results a 70 micron mesh size resulted in the highest microalgal recovery rate and was subsequently used for all dewatering tests conducted in this study. Belt dewatering tests conducted on untreated microalgal suspensions - pond water at the KU Field Station and stationary growth phase samples from the microalgal lab culture - resulted in negligible recovery. The highest concentration of microalgal suspension available for testing on the prototype belt filtration system was 6 g dry wt. /L obtained from biomass settling tanks at the Lawrence, Kansas domestic wastewater treatment plant that resulted in 84% biomass recovery. To further investigate this, 54 Liters of 4 g dry wt. /L were produced from bench-scale flocculation using an alum dosage of 200 mg/L at pre-test pH value of 6.5. Results of belt dewatering tests indicated that the percent of microalgae recovered for 4 g dry wt. /L suspension, 46%, was significantly lower than 6 g dry wt. /L suspension. Sealed filter section would likely improve the microalgal recovery (subsequently reducing the number of filtration passes required for maximum microalgal recovery)

Elmer FEM-Dakota: A unified open-source computational framework for electromagnetics and data analytics

Open-source electromagnetic design software, Elmer FEM, was interfaced with data analytics toolkit, Dakota. Furthermore, the coupled software was validated against a benchmark test. The interface developed provides a unified open-source computational framework for electromagnetics and data analytics. Its key features include uncertainty quantification, surrogate modelling and parameter studies. This framework enables a richer understanding of model predictions to better design electric machines in a time sensitive manner

Influence of stress triaxiality on fracture ductility for stereo lithography

Stress triaxiality is one of the most important factors that controls fracture ductility. The objective of this study was to investigate the influence of stress triaxiality on fracture ductility for specimens’ printed using stereolithography (SL). Dog bone shape specimens were printed using Formlabs® Form 2 Desktop SLA 3D printer. The specimens were built layer by layer with the help of this 3D printer. Each layer of liquid photopolymer is solidified through a computer-controlled ultraviolet (UV) light source with a laser spot size of 140 m. A photopolymer resin supplied by the manufacturer which comprised of a proprietary mix of Methacrylated oligomers, Methacrylated monomer, photo initiators and trace amount of pigments and additives was used for printing the specimens. The length of the specimens was 92.06 mm and the width of the specimens in the gage length portion was 6 mm. Uniaxial tensile tests were conducted on 3D printed specimens. Numerical simulations of the uniaxial tensile tests were performed using the commercial finite element code, ABAQUS. Material properties of 3D printed specimens were calibrated using Abaqus/Isight. The stress triaxiality distribution in the critical cross section at a displacement corresponding to fracture displacement was evaluated. The maximum and average stress triaxialities at the critical cross section was recorded. Triaxiality versus equivalent strain to fracture was plotted for the tested specimens. The results indicate a strong dependence of fracture ductility on stress triaxiality for the 3D printed specimens investigated in this study.https://commons.und.edu/me-pp/1000/thumbnail.jp

ANTIMICROBIAL STUDY OF VYADHIVIDHWANSANA RASA (AN HERBOMINERAL PREPARATION): IN VITRO STUDY

Ayurveda-The traditional medicinal science in India has holistic approach and practiced widely in the subcontinent. Large parts of the Ayurvedic drugs are heromineral preparations. These preparations are broad spectrum as far as its indications are concerned. Definite mode of action of these drugs are inexplicable. Vyadhividhwansana Rasa is an herbomineral preparation used for treating acute fever, interrupted fever, fever of unknown origin, ascites, splenomegaly, colic pain, Vata vyadhi, Aama jwara (first stage of fever) and Vishama jwara (irregular fever). In view of its therapeutic indications an antimicrobial study was designed to ascertain its probable mode of action. The present study aims to evaluate the antimicrobial activity of Vyadhividhwansana Rasa against test organisms at different concentration. Vyadhividhwansana Rasa was prepared as per Ayurvedic texts. Positive control Streptomycin [5mg(w/v)] and negative control 20% dimethyl sulfoxide (DMSO) were prepared. Solution of Vyadhividhwansana Rasa were prepared in three concentrations at 50 mg/ml, 100 mg/ml and 150 mg/ml in DMSO and was tested for its antimicrobial activity against Escherichia coli, Streptococcus pyogenes, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi by agar-well diffusion method. The measured Inhibition Zone ranged from 4-34 mm for all the sensitive bacteria. All the bacteria except Salmonella typhi were found Susceptible (S) against Vyadhividhwansana Rasa compared to standard. Salmonella typhi was found Intermediate sensitive (I). The antimicrobial activity of the extracts increased when the solution is more concentrated

The choice of a constitutive formulation for modeling limb flexion-induced deformations and stresses in the human femoropopliteal arteries of different ages

Open and endovascular treatments for peripheral arterial disease are notorious for high failure rates. Severe mechanical deformations experienced by the femoropopliteal artery (FPA) during limb flexion and interactions between the artery and repair materials play important roles and may contribute to poor clinical outcomes. Computational modeling can help optimize FPA repair, but these simulations heavily depend on the choice of constitutive model describing the arterial behavior. In this study finite element model of the FPA in the standing (straight) and gardening (acutely bent) postures was built using computed tomography data, longitudinal pre-stretch and biaxially determined mechanical properties. Springs and dashpots were used to represent surrounding tissue forces associated with limb flexion-induced deformations. These forces were then used with age-specific longitudinal pre-stretch and mechanical properties to obtain deformed FPA configurations for seven age groups. Four commonly used invariant-based constitutive models were compared to determine the accuracy of capturing deformations and stresses in each age group. The four-fiber FPA model most accurately portrayed arterial behavior in all ages, but in subjects younger than 40 years, the performance of all constitutive formulations was similar. In older subjects, Demiray (Delfino) and classic two-fiber Holzapfel–Gasser–Ogden formulations were better than the Neo-Hookean model for predicting deformations due to limb flexion, but both significantly overestimated principal stresses compared to the FPA or Neo-Hookean models

Anticataleptic activity of various extracts of the aerial parts of Achyranthes aspera

Achyranthes aspera is traditionally used in the treatment of cough and bronchitis and therefore it was our objective to study the effect various extracts of the plant on clonidine and haloperidol induced catalepsy to study its antihistaminic effect. Petroleum ether extract (200 mg/kg, i.p.) of the plant significantly inhibited clonidine-induced catalepsy but not inhibited haloperidol-induced catalepsy. This proves the antihistaminic activity of the plant. The extract was standardized by HPTLC in presence of standard β-sitosterol, which proves that the antihistaminic activity may be due to β-sitosterol.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Beneficial impacts of goat milk on the nutritional status and general well-being of human beings: Anecdotal evidence

Goats provide an essential food supply in the form of milk and meat. Goat milk has distinct qualities, but it shares many similarities with human and bovine milk regarding its nutritional and therapeutic benefits. Because of their different compositions, goat and cow milk products could have different tastes, nutrients, and medicinal effects. Modification in composition aid of goat milk determining the viability of goat milk processing methods. Comparatively, goat's milk has higher calcium, magnesium, and phosphorus levels than cow's or human milk but lower vitamin D, B12, and folate levels. Goat milk is safe and healthy for infants, the old, and healing ailments. Capric, caprylic, and capric acid are three fatty acids that have shown promise as potential treatments for various medical issues. Considering the benefits and drawbacks of goat milk over cow milk is essential; goat milk is more digestible, has unique alkalinity, has a better buffering capacity, and has certain medicinal benefits. Acidifying goat milk shrinks fat globules and makes protein friable (with less αs1-casein and more αs2-casein). Goat milk treats malabsorption illnesses because it has more short- and medium-chain triglycerides that give developing children energy. In wealthy countries, goat milk and its products—yoghurt, cheeses, and powdered goods—are popular with connoisseurs and persons with allergies and gastrointestinal issues who need alternative dairy products. A food product category containing fermented goat milk with live probiotic microbes appears promising nutritionally and medicinally. This article presents anecdotal evidence of the therapeutic effects of consuming goat milk for human health and its nutritional value

OpenFOAM Dakota interface

Traditionally, multi-physics/phase simulation software programs lack tools for uncertainty quantification and optimization. More recently, there is a growing body of research that has integrated these tools into multi-physics/phase simulation software programs [1-4]. Building on this methodology, the study integrated open-source software programs, OpenFOAM [5] for multi-physics/phase simulations and DAKOTA [6] for optimization and uncertainty quantification. Furthermore, the coupled software was successfully applied to benchmarks. The overarching goal was to develop an open-source framework for multi-physics/phase simulations, optimization and uncertainty quantification. The applications of this open-source framework span several industries ranging from aerospace and energy to healthcare and manufacturing.https://commons.und.edu/me-pp/1002/thumbnail.jp

An experimental investigation of microalgal dewatering efficiency of belt filter system

The objective of this study was to investigate the microalgal dewatering efficiency of a belt filter system for feed concentrations below 10 g dry wt./L. A prototype belt filtration system designed for 50 g dry wt./L microalgal feed concentration was used for this investigation. The highest concentration of microalgal suspension available for testing on the prototype belt filtration system was 6 g dry wt./L obtained from biomass settling tanks at the Lawrence, Kansas domestic wastewater treatment plant. For preparation of feed suspension with concentrations below 10 g dry wt./L, microalgal cultivation was followed by flocculation. A mixed laboratory culture of freshwater species dominated by three eukaryotic green microalgae (Chlorella vulgaris, Scenedesmus sp., and Kirchneriella sp.) was cultivated in wastewater effluent. This was followed by flocculation which resulted in a microalgal feed suspension concentration of 4 g dry wt./L. Belt dewatering tests were conducted on microalgal suspensions with feed concentrations of 4 g dry wt./L and 6 g dry wt./L. The maximum microalgal recovery with the belt dewatering system was 46% from the 4 g dry wt./L, and 84% from the 6 g dry wt./L suspensions respectively. The results of this study indicate that microalgal suspension concentrations as low as 6 g dry wt./L can be recovered with a belt filter system improving the overall dewatering efficiency of the system