Low Concentrated Research Articles

Effects of 8 Weeks Feeding Diet with Low and High Isoflavones Soy Protein Concentrate on Serum Isoflavones in Non-alcoholic Fatty Liver Disease (NAFLD) Rat Model

ObjectivesTo examine the effects of 8 weeks feeding of low and high isoflavones levels in soy protein concentrate on the total serum isoflavones in a NAFLD obese rat model.Methods42 six-week old lean (L, n = 21) and obese (O, n = 21) Zucker rats were randomly assigned to 1 of 3 dietary groups: casein diet (C = control), soy protein with low isoflavones (LIF), or soy protein with high isoflavones (HIF) for 8 weeks (n = 7 rats/group). Rats were weighed twice weekly. After 8 weeks, all rats were sacrificed and serum for total isoflavones (genistein, daidzein and equol) were measured using a validated UPLC-MS/MS method and quantified utilizing stable-labeled internal standards.ResultsObese rats gained significantly more weight (P < 0.0001) than lean rats for all three diet groups. There was no detectable serum IF for both LC and OB groups. The mean ± SD for LIF vs HIF serum total IF (uM) for genistein were; (0.11 + 0.04 vs 2.55 + 1.04; p < 0.001), daidzein (0.07 + 0.02 vs 1.14 + 0.45; p < 001) and equol (0.07 + 0.03 vs 1.84 + 0.8; p < 0.001). For OLIF vs OHIF serum genistein were; (0.22 + 0.08 vs 3.69 + 1.52; p < 0.001), daidzein (0.12 + 0.04 vs 1.58 + 0.70; p < 001) and equol (0.06 + 0.03 vs 2.40 + 0.7; p < 0.001). Comparing serum genistein LLIF vs OLIF; p < 0.05 for Daidzein p < 0.05 and equol p = 0.86.ConclusionsHigh isoflavones soy protein concentrate compared to low isoflavones increased serum genistein and daidzein but had no effects on serum equol in a NAFLD rat model.Funding SourcesThis project is support USDA #12889791 to RH.

A significantly improved polymer||Ni(OH)2 alkaline rechargeable battery using anthraquinone-based conjugated microporous polymer anode

Alkaline rechargeable batteries (ARBs) are predicted to be an attractive solution for large-scale electrochemical energy storage applications. However, their advancement is greatly hindered by the lack of high-performance and sustainable anode that can stably operate in less-corroding, low electrolyte concentration. Herein, we report the first example of polymer ARB able to operate in low concentrate electrolyte (1м potassium hydroxide [KOH]) due to the employment of a robust anthraquinone-based conjugated microporous polymer (IEP-11) as anode. The assembled IEP-11||Ni(OH)2 achieves high cell voltage (0.98 V), high gravimetric/areal capacities (150 mAh/g/7.2 mAh/cm2 at 3.5 and 65 mg/cm2, respectively), long cycle life (22,730 cycles, 960 h, 75% capacity retention at 20C), excellent rate performance (75 mAh/g at 50C) and low temperature operativity (75 mAh/g at −10 °C). Furthermore, rate capability, low-temperature performance and ability to prepare high mass loading anodes, along with low self-discharge is improved compared to conventional linear poly (anthraquinone sulfide) (PAQS) in commonly used 10 м KOH. This overall performance for IEP-11||Ni(OH)2 is not only far superior to that of PAQS||Ni(OH)2 owing to porous polymer's high specific surface area, combined micro-/mesoporosity and robust and mechanically stable three-dimensional (3D) architecture compared to the linear PAQS, but also surpass most of the reported organic||nickel [Ni]/cobalt [Co]/manganese [Mn] alkaline rechargeable batteries (ARBs).

Quantum Dot–Block Copolymer Hybrids for Low Scattering Luminescent Solar Concentrators

Quantum Dot–Block Copolymer Hybrids for Low Scattering Luminescent Solar Concentrators

Maximization of the output power of low concentrating photovoltaic systems by the application of reflecting mirrors

Solar energy is among the most commonly used sources of renewable energy since sun is available for a significant portion of the year in most parts of the world. Energy from sun can be harnessed through several technologies with continuous progress and development. Concentrated solar power systems apply mirrors or lenses as well as solar tracking systems for the concentration of a large solar radiation area into a tiny PV area. Due to high price of solar panels, several efficiency enhancement methods are being evaluated by researchers throughout the world. In this research, a form of solar technology, i.e. photovoltaic system, was applied to present developed low concentrator photovoltaic system (LCPVS) with cooling. This project aimed to determine how solar panel power output was changed by the application of mirrors to concentrate solar radiation; which they had concentration onto panel for increasing power output from 1 to 4 mirrors with the cooling system. In fact, the aim was to increase the output power by enhancing the amount of solar radiation which reaches the same surface area of solar panel via mirrors. Furthermore, application of mirrors saves PV area which is more economical. Also, the results were compared to a reference solar panel for determining how to increase the power output of a single panel (normal panel receiving solar radiation directly). The results showed that the value of the DC current (A) output of the four mirrors reflecting on the panel is three times greater than that of the reference panel, and the DC power (W) is almost three times greater than the reference panel's power.

The Remodeling Effects of High-Concentrate Diets on Microbial Composition and Function in the Hindgut of Dairy Cows.

At present, research on high-concentrate (HC) diets mostly focused on the rumen, and there is a paucity of information on the hindgut microbiota of dairy cows. In the present study, a 2 × 2 crossover design with four healthy Holstein cows was used, and the metagenomics approach was adopted to reveal the remodeling effects of HC diets on hindgut microbiota and their metabolic functions. Results showed that, compared with the low-concentrate (LC) diets, HC diets have markedly decreased (p < 0.05) the abundance of cellulolytic bacteria (such as Fibrobacter, Ruminococcus, and Ruminiclostridium) and methanogens (such as Methanobrevibacter, Methanosarcina, and Methanosphaera); and correspondingly, HC diets have significantly reduced (p < 0.05) the abundance of carbohydrate-active enzymes (CAZy) related to hemicellulases (GH10, GH11, and GH54) and cellulases (GH1, GH44, and GH45) and increased the abundance of one oligosaccharide-degrading enzyme (GH32). Furthermore, 62 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways of hindgut microbiota were affected (p < 0.05) by different dietary treatments, and the major pathways altered by HC diets were “Methane metabolism” (enriched in the LC group), “Lipid metabolism” (enriched in the HC group), and several sub-pathways in “Amino acid metabolism” (such as Phenylalanine metabolism, and Phenylalanine, tyrosine, and tryptophan biosynthesis). Also, the microbial genes involved in the pathways “Methane metabolism” (except 1 gene), “Tryptophan metabolism”, and “Phenylalanine metabolism” were all decreased (p < 0.05) in the present study. These findings suggested that HC diets caused the remodeling of hindgut microbiota and its potential functions, and these results may benefit in gaining a deeper understanding of the impact of HC diets on the hindgut microbiota of dairy cows.

A high-concentrate diet provokes inflammation, endoplasmic reticulum stress, and apoptosis in mammary tissue of dairy cows through the upregulation of STIM1/ORAI1

High-concentrate feeding can induce subacute ruminal acidosis, which leads to mammary tissue injury in dairy cows. Therefore, the purpose of this research was to evaluate the effect of high-concentrate feeding on STIM1 (stromal interaction molecule 1)/ORAI1 (Orai calcium release-activated calcium modulator 1)-mediated inflammation, endoplasmic reticulum stress (ERS), and apoptosis in the mammary tissue of dairy cows. A total of 12 healthy mid-lactating Holstein cows of similar weight were randomly allotted into the following 2 groups: a high-concentrate (HC) group (concentrate:forage = 6:4) and a low-concentrate (LC) group (concentrate:forage = 4:6). The trial lasted for 3 wk. After the feeding experiment, rumen fluid, lacteal vein blood, and mammary tissue samples were collected. The results showed that the HC diet significantly increased blood lipopolysaccharide levels, decreased ruminal pH, and upregulated the concentrations of Ca2+ and proinflammatory cytokines, including TNF-α, IL-1β, and IL-6, and the enzyme activities of caspase-3, caspase-9, PKC, and IKK. The upregulation of STIM1, ORAI1, PKCα, IKKβ, phosphorylated-IκBα, phosphorylated-p65, TNF-α, and IL-1α proteins in the HC group indicated activation of the STIM1/ORAI1-mediated inflammatory signaling pathway compared with that in the LC group. The HC diet also induced ERS by increasing the mRNA and protein abundances of GRP78, CHOP, PERK, ATF6, and IRE1α in the mammary tissue. Compared with the LC group, the mRNA expression levels and protein abundances of caspase-3, cleaved caspase-3, caspase-9, and BAX were markedly increased in the HC group. However, the mRNA and protein expression levels of Bcl-2 were significantly decreased in the HC group. Therefore, this study demonstrated that the HC diet can activate the store-operated calcium entry channel by upregulating the expression of STIM1 and ORAI1 and induce inflammation, ERS, and apoptosis in the mammary tissue of dairy cows.

Elevated thyroid hormones caused by high concentrate diets participate in hepatic metabolic disorders in dairy cows.

ObjectiveHigh concentrate diets are widely used to satisfy high-yielding dairy cows; however, long-term feeding of high concentrate diets can cause subacute ruminal acidosis (SARA). The endocrine disturbance is one of the important reasons for metabolic disorders caused by SARA. However, there is no current report about thyroid hormones involved in liver metabolic disorders induced by a high concentrate diet.MethodsIn this study, 12 mid-lactating dairy cows were randomly assigned to HC (high concentrate) group (60% concentrate of dry matter, n = 6) and LC (low concentrate) group (40% concentrate of dry matter, n = 6). All cows were slaughtered on the 21st day, and the samples of blood and liver were collected to analyze the blood biochemistry, histological changes, thyroid hormones, and the expression of genes and proteins.ResultsCompared with LC group, HC group showed decreased serum triglyceride, free fatty acid, total cholesterol, low-density lipoprotein cholesterol, increased hepatic glycogen, and glucose. For glucose metabolism, the gene and protein expression of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase 1 in the liver were significantly up-regulated in HC group. For lipid metabolism, the expression of sterol regulatory element-binding protein 1, long-chain acyl-CoA synthetase 1, and fatty acid synthase in the liver was decreased in HC group, whereas carnitine palmitoyltransferase 1α and peroxisome proliferator activated receptor α were increased. Serum triiodothyronine, thyroxin, free triiodothyronine (FT3), and hepatic FT3 increased in HC group, accompanied by increased expression of thyroid hormone receptor (THR) in the liver.ConclusionTaken together, thyroid hormones may increase hepatic gluconeogenesis, β-oxidation and reduce fatty acid synthesis through the THR pathway to participate in the metabolic disorders caused by a high concentrate diet.

Controlled and Local Delivery of Antibiotics by 3D Core/Shell Printed Hydrogel Scaffolds to Treat Soft Tissue Infections.

Soft tissue infections in open fractures or burns are major cause for high morbidity in trauma patients. Sustained, long-term and localized delivery of antimicrobial agents is needed for early eradication of these infections. Traditional (topical or systemic) antibiotic delivery methods are associated with a variety of problems, including their long-term unavailability and possible low local concentration. Novel approaches for antibiotic delivery via wound coverage/healing scaffolds are constantly being developed. Many of these approaches are associated with burst release and thus seldom maintain long-term inhibitory concentrations. Using 3D core/shell extrusion printing, scaffolds consisting of antibiotic depot (in the core composed of low concentrated biomaterial ink 3% alginate) surrounded by a denser biomaterial ink (shell) were fabricated. Denser biomaterial ink (composed of alginate and methylcellulose or alginate, methylcellulose and Laponite) retained scaffold shape and modulated antibiotic release kinetics. Release of antibiotics was observed over seven days, indicating sustained release characteristics and maintenance of potency. Inclusion of Laponite in shell, significantly reduced burst release of antibiotics. Additionally, the effect of shell thickness on release kinetics was demonstrated. Amalgamation of such a modular delivery system with other biofabrication methods could potentially open new strategies to simultaneously treat soft tissue infections and aid wound regeneration.

Noble metals doped tin dioxide for sodium hypochlorite synthesis from low concentrated NaCl solutions

AbstractBACKGROUNDCreation of anode materials with high selectivity to the target process is the main problem in low concentration sodium chloride (NaCl) solutions. A specificity of such solutions is the achievement of high potentials at which the anodes traditionally used for the synthesis of chlorine [rutile oxide/titania (RuO2‐TiO2)] are destroyed. The main aim of the work concerns the eveluation of the effect of platinum (Pt) group metals in a tin oxide (SnO2) matrix on the electrocatalytic activity and selectivity in reactions of the synthesis of sodium hypochlorite and chlorate (NaClO and NaClO3) and oxygen (O2) evolution.RESULTSIt was revealed that palladium (Pd) in oxide Ti/SnO2‐Pd and Ti/SnO2‐Pt‐Pd coatings existed in the PdO form, which has a high affinity for hydroxylation. Electrocatalytic activity of coatings in anode processes in low concentrated chloride‐containing solutions would be determined by the bond strength of chemisorbed with the surface O‐containing particles. Participation in the process of Cl‐ oxidation of labile O‐containing particles increased the rate of formation of NaClO and led to inhibition of adverse reactions of O2 evolution and synthesis of chlorates and chlorites.CONCLUSIONA correlation between the selectivity of formation of NaClO and NaClO3, and the activity of the catalyst in the O2 evolution reaction is proposed. Significant formation of chlorates occurred only at the anodes, where in 1 mol L–1 HClO4 the O2 evolution potential was &gt;1.58 V. Parameters influencing the electrocatalytic activity and selectivity of electrode materials in the target process were proposed based on this dependence. © 2021 Society of Chemical Industry (SCI).

Performance evaluation of concentrator photovoltaic systems integrated with combined passive cooling techniques

Enhancing the performance of concentrator photovoltaic cells integrated with passive heat sinks is essential. The objective of the present work is to boost the performance of combined fins and phase change materials (PCMs) as passive cooling for low concentrator photovoltaic systems during phase transition and after complete melting. Thus, a new passive heat sink is presented, including extended aluminum fins outside the PCM containeras a viable solution to elongate the PCM melting time and prevent temperature rise after the PCM completely melted.The developed design is compared with other different heat sinks such as fins, aluminum heat sink with PCM, andaluminum heat sink withfour parallel cavitiesfilled with PCM. A comprehensive two-dimension model for photovoltaic layers with integrated phase change material and extended fins is developed to predict the average solar cell temperature, conversion efficiency, and energy budget for each design at different concentration ratios. The model is numerically simulated and validated with the available experimental and numerical data. Results indicate thatthe use of PCM for passive cooling enhances solar cell thermal regulation during solid–liquid phase transition process due to latent heat absorption and maintains the solar cell temperature around 60 °C at concentration ratio of 5 suns. However, the PCM cooling capability is significantly reduced after the dissipation of its latent heat. At concentration ratio of 5, by using an aluminum heat sink with PCM, andwithfour parallel cavitiesfilled with PCM, the steady state solar cell temperature rises to 120 °C and 125 °C, respectively. However, the developed heat sink with extended aluminum fins outside the PCM container elongates the melting timeand prevents temperature rise after the PCM fully melted, sustaining a steady state temperature of around 82 °C. Accordingly, the new design of heat sink is able to maintain the steady state solar cell temperature below the maximum permissible temperature with the capability of storing thermal energy.

A new sensitive and fast assay for the detection of EGFR mutations in liquid biopsies.

A major perspective for the use of circulating tumor DNA (ctDNA) in the clinical setting of non-small cell lung cancer (NSCLC) is expected as predictive factor for resistance and response to EGFR TKI therapy and, especially, as a non-invasive alternative to tissue biopsy. However, ctDNA is both highly fragmented and mostly low concentrated in plasma and serum. On this basis, it is important to use a platform characterized by high sensitivity and linear performance in the low concentration range. This motivated us to evaluate the newly developed and commercially available SensiScreen® EGFR Liquid assay platform (PentaBase) with regard to sensitivity, linearity, repeatability and accuracy and finally to compare it to our already implemented methods. The validation was made in three independent European laboratories using two cohorts on a total of 68 unique liquid biopsies. Using artificial samples containing 1600 copies of WT DNA spiked with 50% - 0.1% of mutant copies across a seven-log dilution scale, we assessed the sensitivity, linearity, repeatability and accuracy for the p.T790M, p.L858R and exon 19 deletion assays of the SensiScreen® EGFR Liquid assay platform. The lowest value detectable ranged from 0.5% to 0.1% with R2≥0,97 indicating good linearity. High PCR efficiency was shown for all three assays. In 102 single PCRs each containing theoretical one copy of the mutant at initiating, assays showed repeatable positivity in 75.5% - 80.4% of reactions. At low ctDNA levels, as in plasma, the SensiScreen® EGFR Liquid assay platform showed better sensitivity than the Therascreen® EGFR platform (Qiagen) and equal performance to the ctEGFR Mutation Detection Kit (EntroGen) and the IOT® Oncomine cell-free nucleic acids assay (Thermo Fisher Scientific) with 100% concordance at the sequence level. For profiling clinical plasma samples, characterized by low ctDNA abundance, the SensiScreen® EGFR Liquid assay is able to identify down to 1 copy of mutant alleles and with its high sensitivity, linearity and accuracy it may be a competitive platform of choice.

Conductometric properties of alcoholic nanosuspensions of metal oxides

In this work, we present the experimental study of nanofluids’ electrophysical characteristics concentration dependencies specific behavior (nanoparticles of Al2O3, ZnO and Fe2O3 in isopropyl alcohol) at low concentrations. The values of a conductivity, electrical capacitance and dielectric permittivity are measured depending on the suspended particles’ concentration for low concentrated nanofluids far from the percolation threshold and for different periods after their preparation. It is shown that the increase of the electrophysical parameters with increasing concentration of the pointed nanoparticles (which themselves are non-conductive) may be explained by a formation of an electrical double layer around the particles and a percolation of particle clusters.

A New Approach for Design Optimization and Parametric Analysis of Symmetric Compound Parabolic Concentrator for Photovoltaic Applications

A compound parabolic concentrator (CPC) is a non-imaging device generally used in PV, thermal, or PV/thermal hybrid systems for the concentration of solar radiation on the target surface. This paper presents the geometric design, statistical modeling, parametric analysis, and geometric optimization of a two-dimensional low concentration symmetric compound parabolic concentrator for potential use in building-integrated and rooftop photovoltaic applications. The CPC was initially designed for a concentration ratio of “2×” and an acceptance half-angle of 30°. A MATLAB code was developed in house to provoke the CPC reflector’s profile. The height, aperture width, and concentration ratios were computed for different acceptance half-angles and receiver widths. The interdependence of optical concentration ratio and acceptance half-angle was demonstrated for a wide span of acceptance half-angles. The impact of the truncation ratio on the geometric parameters was investigated to identify the optimum truncation position. The profile of truncated CPC for different truncation positions was compared with full CPC. A detailed statistical analysis was performed to analyze the synergistic effects of independent design parameters on the responses using the response surface modeling approach. A set of optimized design parameters was obtained by establishing specified optimization criteria. A 50% truncated CPC with an acceptance half-angle of 21.58° and receiver width of 193.98 mm resulted in optimum geometric dimensions.

Determination of γ-D-glutamyl-meso-diaminopimelic acid in rumen fluid of dairy cows by pre-column chiral derivatization-HPLC

High concentrate (HC) diet feeding leads to the lysis of rumen microbes and the release of hazardous metabolites, which can trigger inflammatory responses, thereby impairing dairy cow health and production. γ-D-glutamyl-meso-diaminopimelic acid (iE-DAP), which constitutes the peptidoglycan (PGN) layer of bacteria, is the minimum PGN structure capable of activating inflammatory signaling pathways. This research paper aimed to determine the iE-DAP concentration and investigate the effects of an HC diet on the concentration of iE-DAP in the rumen fluid of dairy cows. However, there are limited studies on the determination of iE-DAP concentration. Hence, we established a high-performance liquid chromatography (HPLC) method combined with pre-column chiral derivatization to detect the concentration of iE-DAP in rumen fluid. Moreover, we conducted an animal experiment that included 12 lactating Holstein cows, which were randomly divided into a low-concentrate (LC) group and an HC group. The results showed that the linear range of iE-DAP was 5–500 µg/mL and that the intra- and inter-day RSDs were lower than 7%. Meanwhile, this method was successfully applied to the analysis of iE-DAP in rumen fluid, and the results revealed that long-term feeding with an HC diet elevated the concentration of iE-DAP in rumen fluid of dairy cows.

Low concentrated phosphorus sorption in aqueous medium on aragonite synthesized by carbonation of seashells: Optimization, kinetics, and mechanism study

Phosphorus (P) concentration beyond threshold limit can trigger eutrophication in stagnant water bodies nevertheless it is an indispensable macronutrient for aquatic life. Even in low P concentration (≤1 mg L−1), P can be detrimental for ecosystem's health, but this aspect has not been thoroughly investigated. The elimination of low P content is rather expensive or complex. Therefore, a unique and sustainable approach has been proposed in which valorized bivalve seashells can be used for the removal of low P content. Initially, acicular shaped aragonite particles (~21 μm) with an aspect ratio of around 21 have been synthesized through the wet carbonation process and used to treat aqueous solutions containing P in low concentration (P ≤ 1 mg L−1). Response surface methodology based Box-Behnken design has been employed for optimization study which revealed that with aragonite dosage (140 mg), equilibrium pH (~10.15), and temperature (45 °C), a phosphorus removal efficiency of ~97% can be obtained in 10 h. The kinetics and isotherm studies have also been carried out (within the range P ≤ 1 mg L−1) to investigate a probable removal mechanism. Also, aragonite demonstrates higher selectivity (>70%) towards phosphate with coexisting anions such as nitrate, chloride, sulfate, and carbonate. Through experimental data, elemental mapping, and molecular dynamic simulation, it has been observed that the removal mechanism involved a combination of electrostatic adsorption of Ca2+ ions on aragonite surface and chemical interaction between the calcium and phosphate ions. The present work demonstrates a sustainable and propitious potential of seashell derived aragonite for the removal of low P content in aqueous solution along with its unconventional mechanistic approach.

Development of high‐efficiency and low‐cost solar cells for PV‐powered vehicles application

AbstractDevelopment of high‐efficiency solar cell modules and new application fields are significant for the further development of photovoltaics (PVs) and the creation of new clean energy infrastructure based on PV. Notably, the development of PV‐powered vehicle applications is desirable and very important for this end. According to the NEDO's Interim Report “PV‐Powered Vehicle Strategy Committee,” a new broader PV markets with more than 10 GW and 50 GW in 2030 and 2040, respectively, are expected to be established when PV‐powered vehicles are developed. Cumulative PV capacity for PV‐powered vehicles will be 50 GW and 0.4 TW in 2030 and 2040, respectively. This paper presents impacts on efficiency and cost for PV‐powered vehicles. According to our survey, the use of more than 30% of high‐efficiency PV enables 30 km per day driving without external charging and the society that the majority of the family cars run by the sunlight and without supplying gas. Thus, we are developing high‐efficiency and low‐cost solar cells and modules for automobile applications. In this paper, our analytical results for the efficiency potential of various solar cells for choosing candidates of high‐efficiency solar cell modules for automobile applications. This paper also presents our recent approaches: demonstration car (Toyota Prius PHV) by using Sharp's high‐efficiency III‐V triple‐junction solar cell modules with an output power of 860 W, static low concentrator InGaP/GaAs/InGaAs triple‐junction solar cell module with efficiency of 32.84%, and so forth.

Performance enhancement of concentrator photovoltaic systems using nanofluids

In the current study, a newly developed low photovoltaic concentrator (LCPV) equipped with nanofluid-based cooling channels, directly contacting the rare LCPV, was examined in detail. Nanofluid acts as a coolant that flowing over the back of LCPV to maintain its optimal operating temperature with the best overall performance. The coolants used are water and aluminum oxide (Al2O3)/water nanofluids 1%, 2%, and 3% by volume concentration. When circulating a 3%-Al2O3/water nanofluid, the temperature of the LCPV module is dropped by 16.47°C compared to the uncooled module and keeps its operating temperature under 45°C during the experimental tests. This reduction in the LCPV module temperature with V-trough reflector mirrors in turn increased its performance. The results revealed that the daily electrical output power of the uncooled LCPV module was 1646.85 W, whereas, was 1870.55 W with (13.58%) improvement with the case of water cooling. However, cooling with 3%-Al2O3/water nanofluid, the power output of the LPVC was 2319.88 W with (24.02%) and (40.86%) enhancement compared to pure water cooling and without cooling respectively. The rise in the volume fraction ratio of Al2O3 nanoparticles remarkably decreases the operating temperature of the LCPV module and improves both electrical and thermal efficiency.

Low Cost High-Accuracy Compound Parabolic Concentrator System—A Manufacturing Methodology

Abstract One of the problems of designing a solar compound parabolic concentrator (CPC) is related to its manufacturing shape accuracy. The complexity of curving and holding the CPC profile in place is indeed a challenging issue, especially because there are no standardized molds and the process is typically handmade. It is very easy to provoke misalignment on the CPC surface and in consequence, divert the solar incident rays, affecting significantly the optical efficiency of the system. This work presents a novel, inexpensive methodology to manufacture a CPC with accuracy by using basic tools. The design starts with the acquisition of a pair of medium-density fiberboard wooden templates of the CPC profile that are used later to make a Styrofoam CPC mold and then cut with a hot-wire technique. A high-reflectance anodized aluminum sheet is curved to approximate the CPC shape and is then coupled with the temporary Styrofoam mold. The last part consists of the elaboration of a housing system to contain the parts. This is consolidated by a polyurethane resin that expands and fills all enclosure cavities, offering stiffness and stability. A photogrammetry analysis was implemented for the validation of the surface shape accuracy. The results from the optical analysis show that this technique achieved a high degree of accuracy and homogeneity on the CPC surface shape.

Effect of high-concentrate diets on microbial composition, function, and the VFAs formation process in the rumen of dairy cows

Although numerous studies have revealed the effects of high-concentrate (HC) diets on rumen microbial composition and metabolism, information regarding changes in the volatile fatty acids (VFAs) formation process under HC feeding is still limited. In the present study, we used a metagenomics approach to compare the effects of low-concentrate (LC) diets and high-concentrate (HC) diets on alterations to the rumen microbiota and their functions, particularly the functional genes involved in the metabolic routes of VFAs. The results showed that the HC diets increased (P < 0.05) the relative abundance of Eubacterium spp., Clostridium spp., Ruminococcus spp., Lactobacillus, and Bifidobacterium spp. and decreased (P < 0.05) the relative abundance of Prevotella spp., Fibrobacter succinogenes, and Bacteroides spp. The changes in rumen microbial composition further resulted in corresponding alterations in microbial function. Results regarding the carbohydrate-active enzymes revealed that the HC diets increased (P < 0.05) the abundance of glycoside hydrolases 13 (GH13; α-amylase activity), carbohydrate-binding module 26 (CBM26; starch-binding function), and CBM34 (starch-binding function) and simultaneously decreased (P < 0.05) the abundance of cellulases (GH5, GH9 and GH51). During the process of starch–pyruvate–VFAs, the HC diets increased (P < 0.05) the abundance of genes encoding pyruvate kinase (PK), pyruvate ferredoxin oxidoreductase (PFOR), and L-lactate dehydrogenase (LDH), which may be a reason behind the accumulation of rumen butyrate and propionate in the present study. Overall, these results clarified the mechanism behind how HC diets affect the formation process of rumen VFAs and provided new insight into the effect of HC diets on rumen microbiota.

Tailoring the graphene polarity through the facile and one-step electrochemical exfoliation in low concentration of exfoliation agents

Graphene nanoplatelets with different oxidation degrees, from low polar few-layer graphene (FLG) to high polar graphene oxide (GO) in the same current and concentration of the oxidizing agent in low concentrated electrolytes ((NH4)2SO4, Sodium Do-decyl Sulfate (SDS), and HNO3) are prepared through a one-step and cost-effective electrochemical synthesis route to find the effect of electrolyte on the surface polarity of powders. In order to use a wide variety of electrolytes, basic, neutral, and acidic electrolytes in a concentration as low as 0.2 M are used. Exfoliated graphene nanoplatelets without any further process are obtained to simplify and accelerate the synthesis process. Several characterization methods including XRD, FTIR, TGA, RAMAN, XPS, and UV–Vis tests and electrical conductivity measurement are used to characterize the prepared samples, comprehensively. Results show that the synthesized sample using (NH4)2SO4, neutral electrolyte, is a mixture of FLG and unreacted graphite with the C/O ratio of 4.21, while the sample obtained in SDS, basic electrolyte, is a mixture of FLG, GO, and unreacted graphite with the C/O ration of 2.21. The synthesized sample in HNO3, acidic electrolyte, is a mixture of mainly GO (96.2%) and unreacted graphite (3.8%) with the C/O ratio of 1.22 which is much lower than synthesized powder by Hummers method. The polarity of samples changes dramatically by altering the electrolyte and this can be can be utilized to prepare the graphene nanoplatelets with desired polarity for a specific application.