Scientists using the Advanced Photon Source show how ‘zinc sparks’ — the showers of zinc ions released by mammalian eggs immediately after fertilization — also occur in amphibian eggs.
Five years ago, researchers at Northwestern University made international headlines when they discovered that human eggs, when fertilized by sperm, release billions of zinc ions, dubbed “zinc sparks.”
Now, Northwestern has teamed up with the U.S. Department of Energy’s (DOE) Argonne National Laboratory and Michigan State University (MSU) to reveal that these same sparks fly from highly specialized metal-loaded compartments at the egg surface when frog eggs are fertilized. This means that the early chemistry of conception has evolutionary roots going back at least 300 million years, to the last common ancestor between frogs and people.
“This work may help inform our understanding of the interplay of dietary zinc status and human fertility.” — Thomas O’Halloran, professor, Michigan State University
And the research has implications beyond this shared biology and deep-rooted history. It could also help shape future findings about how metals impact the earliest moments in human development.
“This work may help inform our understanding of the interplay of dietary zinc status and human fertility,” said Thomas O’Halloran, the senior author of the research paper published on June 21, 2021, in the journal Nature Chemistry.
O’Halloran was part of the original zinc spark discovery at Northwestern and, earlier this year, he joined Michigan State as a foundation professor of microbiology and molecular genetics and chemistry. O’Halloran was the founder of Northwestern’s Chemistry of Life Processes Institute, or CLP, and remains a member.
The team also discovered that fertilized frog eggs eject another metal, manganese, in addition to zinc. It appears these ejected manganese ions collide with sperm surrounding the fertilized egg and prevent them from entering.
“These breakthroughs support an emerging picture that transition metals are used by cells to regulate some of the earliest decisions in the life of an organism,” O’Halloran said.
To make these discoveries, the team needed access to some of the most powerful microscopes in the world as well as expertise that spanned chemistry, biology and X-ray physics. That unique combination included collaborators at the Center for Quantitative Element Mapping for the Life Sciences, or QE-Map, an interdisciplinary National Institutes of Health-funded research hub at MSU and Northwestern’s CLP. The research relied heavily on the tools and expertise available at Argonne.
The research team brought sections of frog eggs and embryos to Argonne for analysis. Using both X-ray and electron microscopy, the researchers determined the identity, concentrations, and intracellular distributions of metals both before and after fertilization.
X-ray fluorescence microscopy was conducted at beamline 2-ID-D of the Advanced Photon Source (APS), a DOE Office of Science User Facility at Argonne. Barry Lai, group leader at Argonne and an author on the paper, said that the X-ray analysis quantified the amount of zinc, manganese, and other metals concentrated in small pockets around the outer layer of the eggs. They found these pockets contained more than 30 times the manganese as the rest of the eggs, and 10 times the zinc.
“We are able to do this analysis because of the elemental sensitivity of the beamline,” Lai said. “In fact, it is so sensitive that substantially lower concentrations can be measured.”
Complementary scans were conducted using transmission electron microscopy at the Center for Nanoscale Materials (CNM), a DOE Office of Science User Facility at Argonne. Further analysis was performed on a separate prototype scanning transmission electron microscope that includes technology developed by Argonne Senior Scientist Nestor Zaluzec, an author on the paper. These scans were performed at smaller scales — down to a few nanometers, about 100,000 times smaller than the width of a human hair — but found the same results: high concentrations of metals in pockets around the outer layer.
Both X-ray and electron microscopy showed that the metals in these pockets were almost completely released after fertilization.
“Argonne has the tools necessary to examine these biological samples at these scales without destroying them with X-rays or electrons,” Zaluzec said. “It’s a combination of the right resources and the right expertise.”
The APS is in the process of undergoing a massive upgrade, one that will increase the brightness of its X-ray beams by up to 500 times. Lai said that an upgraded APS could complete these scans much more quickly or with higher spatial resolution. What took more than an hour for this research could be done in less than one minute after the upgrade, Lai said.
“We often think of genes as key regulating factors, but our work has shown that atoms like zinc and manganese are critical to the first steps in development after fertilization,” said MSU Provost Teresa K. Woodruff, Ph.D., another senior author on the paper.
Woodruff, an MSU foundation professor and former member of CLP, was also a leader of the Northwestern team that discovered zinc sparks five years ago. With the discovery of manganese sparks in African clawed frogs, or Xenopus laevis, the team is excited to explore whether the element is released by human eggs when fertilized.
“These discoveries could only be made by interdisciplinary groups, fearlessly looking into fundamental steps,” she said. “Working across disciplines at the literal edge of technology is one of the most profound ways new discoveries take place.”
“Xenopus is a perfect system for such studies because their eggs are an order of magnitude larger than human or mouse eggs, and are accessible in large numbers,” said Carole LaBonne, another senior author on the study, CLP member, and chair of the Department of Molecular Biosciences at Northwestern. “The discovery of zinc and manganese sparks is exciting, and suggests there may be other fundamental signaling roles for these transition metals.”
Reference: “Metal ion fluxes controlling amphibian fertilization” by John F. Seeler, Ajay Sharma, Nestor J. Zaluzec, Reiner Bleher, Barry Lai, Emma G. Schultz, Brian M. Hoffman, Carole LaBonne, Teresa K. Woodruff and Thomas V. O’Halloran, 21 June 2021, Nature Chemistry.


Phosphorus Diffusion Retardation in a Calcareous System by Coapplication of Potassium Chloride
- O. O. Akinremi and
- C. M. Cho
The recommended methods of application of P and K fertilizers to agronomic crops are quite similar. As such, both fertilizer elements could be banded together in a single farm operation. This research was conducted to provide information on the influence of K on the mobility and solubility of P added to a system having Ca2+ as the dominant exchangeable ion. Four grams of KH2PO4 was added alone or in combination with 0.11 or 0.22 g of KCl to the surface of a Ca2+-saturated resin-sand column. Extraction and analysis of each 2-mm layer of the column at 2 and 4 wk after incubation showed that the mobility and the solubility of the added P was significantly reduced in the presence of KCl. This was a result of increased precipitation of P by Ca2+ displaced from the exchange sites. Thus, the availability of P to plants could be adversely affected in mixed P-K bands.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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Tempered silicone paint EMEX TRS 400.
Silicone Thermoresistant EMEX TRS 400 is a professional, air-dry, single-component, silicone resin based powder coating, pigments, specific additives and organic solvents. It is a paint with superior film and strength characteristics. After application to metallic elements, the silicone heat-resistant paint dries under the action of high temperature, achieving superior parameters of high temperature resistance or excessive heat. It is produced only in the colors: black and silver.
- High adherence;
- Easy application;
- Short drying time;
- High coverage power;
- Good display;
- Metallic or matt appearance;
- Good hardness;
- Good durability;
- High temperature resistance up to 400 ° C.
Fields of Use:
Higher resistance to high temperature exposure guaranteed up to 400 ° C makes EMEX TRS 400 Silicone Heat Resistant for professional use for painting, decorating and protecting steel and cast iron items that are continuously or temporarily subjected to high temperatures. It is especially recommended for painting the exhaust elements of cars: exhaust pipes, exhaust drums, and industrial furnaces.
Prior to application, in the case of old, non-adherent paints, they are completely removed by scraping, burning with a gasoline lamp, or by using the Emex CM Cleaner special chemical solution or EMEX PC ECO Decapant.
However, for the proper preparation of metallic surfaces it is mandatory to clean by sanding or cleaning by mechanical brushing, followed by dust blowing by compressed air blowing and degreasing with recommended chemicals or solvent.
Priming, where required, will only be recommended by the manufacturer with a heat-resistant silicone primer, as it is the only one that provides total compatibility with EMEX TRS 400, thermo-resisting silicone paint.
It is forbidden to use any chemical or product that could come into contact with this paint without the manufacturer's recommendation.


Technology for the Future: Shimadzu & URI
One of the leading scientific instrument makers in the world, Shimadzu Corporation, will provide the University of Rhode Island’s new Center for Chemical and Forensic Sciences, currently under construction on the Kingston campus, with state-of-the-art instruments at a significant discount, including a full 5-year service plan, an in-kind donation valued at more than $1.2 million.
If the University were to purchase the instruments through normal educational purchase programs, the cost could run up to $2.8 million. The service plan covers technician visits once each semester to the teaching-learning labs and an additional visit each year to the research laboratories.
Based in Japan, Shimadzu Corp. posted $3 billion in consolidated net sales in 2013. Its contribution to URI will ensure that the University has cutting edge instruments and the ability to maintain even heavy demand instruments used by thousands of URI students who take chemistry each year.
To celebrate the partnership, University and Shimadzu officials came together for a signing ceremony on September 10, 2014.
“As many Rhode Islanders who supported this project knew, the Center for Chemical and Forensic Sciences is central to the University’s efforts to continually strengthen teaching and research and help build a strong economic future for the state based on discovery and innovation,” said President David M. Dooley. “When the new building opens, thanks to this generous donation from Shimadzu, our students and faculty will have access to the most advanced laboratory instruments and a program to keep all of them operational. We are fortunate to be able to partner with a company like Shimadzu, which is committed to the success of our University.”
“The University of Rhode Island has a dynamic science program focused on the future, and Shimadzu is pleased and eager to support such a research institution,” said Shuzo Maruyama, president of Shimadzu Scientific Instruments (the American subsidiary of Shimadzu Corp.). “We are delighted to have the opportunity to catalyze the potential of this great institution and look forward to working together in the future.”
Slated to be completed in the spring of 2016, URI’s $68 million Center for Chemical and Forensic Sciences will serve more than 7,000 URI students who take chemistry each year; about 40 percent of all URI degree programs require at least one chemistry class. It will provide chemistry instruction to approximately 1,400 students each day.
Among the instruments that will be found in the teaching and learning labs are: balances, mass spectrometers, gas chromatographs, spectrometers, and liquid chromatographs.
“I am very grateful to the Shimadzu Corporation for providing the students and faculty the instruments they need to engage in 21st century science,” said Winifred Brownell, dean of the College of Arts and Sciences. “This center and all of the instruments contained in it will benefit all Rhode Islanders as it serves as a catalyst for economic development and discoveries that will improve peoples’ health and well-being within our state’s borders and around the world.”


CBD or Cannabidiol is a non-intoxicating cannabinoid found in cannabis. CBD is the second-most abundant cannabinoid in the plant, and has many potential therapeutic benefits compared to tetrahydrocannabinol (THC), which is first in the list. It is also has medicinal benefits like anti-flammatory, analgesic, anti-anxiety and seizure-suppressant properties. CBD is considered as the yang to THC’s yin and it halts anxiety as well as elevates your level of chill without intoxication. The combination of both the THC and CBD components amplifies each others’ effects.
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Duratec High Gloss Additive
Blended with gelcoats for gelcoat repairs; blended with tooling gelcoats to upgrade mold surfaces.
Low Porosity---when used for repairs, blending the additive with gelcoat produces a low porosity surface.
Reduced orange peel---the low viscosity of the blend results in a smooth finish that is easily sanded.
Improved properties---for mold surfaces, the blending of the additive with tooling gelcoat creates a higher heat distortion temperature, improved gloss retention, increased impact resistance and reduced subsurface porosity.
Superior finish---when blended one-to-one with gelcoats, the additive creates an air-cure, enamel-like coating. No air-dry additive is required. When used for gelcoat repair, surfaces are restored to like-new condition.
As measured on a Brookfield Viscometer Model RVF, Spindle #2 at 20 rpm - 110 cps
Thixotropic Index - 1
Sample based on a 100 g mass, catalyzed at 2 percent with mekP - 16-20 min
Weight per Gallon - 8.0 lb., 3.6 kg


Neaton, J.B., Ederer, C., Waghmare, U.V., Spaldin, N.A., Rabe, K.M. 'First-principles study of spontaneous polarization in multiferroic BiFeO3' in Physical Review B - Condensed Matter and Materials Physics, 71, (1), 2005, pp 014113-1 - 014113-8
Physical Review B - Condensed Matter and Materials Physics 71 1
The ground-state structural and electronic properties of ferroelectric BiFeO3 are calculated using density functional theory within the local spin-density approximation (LSDA) and the LSDA + U method. The crystal structure is computed to be rhombohedral with space group R3c, and the electronic structure is found to be insulating and antiferromagnetic, both in excellent agreement with available experiments. A large ferroelectric polarization of 90-100 μC/cm2 is predicted, consistent with the large atomic displacements in the ferroelectric phase and with recent experimental reports, but differing by an order of magnitude from early experiments. One possible explanation is that the latter may have suffered from large leakage currents. However, both past and contemporary measurements are shown to be consistent with the modern theory of polarization, suggesting that the range of reported polarizations may instead, correspond to distinct switching paths in structural space. Modern measurements on well-characterized bulk samples are required to confirm this interpretation.
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Advanced scientific methods dance with exotic plant extracts and vitamins cultivated by Dr.
Rodgers’ extensive travel and research. Cutting-edge technologies blend together while avoiding potentially harsh chemicals, preservatives and harmful ingredients.
All EnPointe Skin Solutions™ products are free of:
The products are NOT tested on animals.
- Growth Factors
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A brief overview of sustained released drug delivery system
Keywords:Sustain release dosage form, drug delivery system, controlled release system, half-life
The most popular and patient-friendly method of drug administration is often thought to be the oral route of administration. Compared to conventional release formulations, advancements in formulation technology, including modified release dosage forms or sustained release oral dosage forms, have been extensively accepted. A sustained release dosage form provides a prolonged release of the drug over an extended period, thereby giving better patient compliance and enhanced bioavailability. Sustain release systems are considered a wiser approach for drugs with short half-lives requiring repeated dosing. Sustained release drug delivery has a range of advantages over conventional dosage forms, including increased patient compliance due to less frequent drug administration, significantly reduced steady state drug level fluctuations, maximum drug utilization, the increased safety margin of potent drugs, lower healthcare costs due to improved therapy, and shorter treatment times. The present review focuses on design, fabrication, and various factors that influence the performance of sustained-release dosage forms.
Bhowmik D, Kumar KPS, Dutta A, Paswan S. Trends in scope and opportunities of control release oral drug delivery systems. Critical Review in Pharmaceutical Sciences, 1(1), 20-33 (2012)
Vamsy KA, Srinath KR, Chowdary PC. Formulation development and evaluation of Divalproex sodium extended release tablet. International Journal of Research pharmaceutical and Biomedical Science, 2(1), 809-832(2011)
Patel H, Panchal DR, Patel U, Brahmbhatt T. Matrix Type Drug Delivery System: A Review. Journal of Pharmaceutical Science and Bioscientific Research, 3(1), 143-51 (2011)
Kumar KPS, Bhowmik D, Srivastava S. Sustained Release Drug Delivery System Potential. The Pharma Inovation, 2(1), 48-60(2017).
Lee TW, and Robinson JR, In Remington: The science and practice of pharmacy, Gennaro, 23th edition, Baltimore, Lippincott Williams and Wilkins, 903-929 (2008).
Ansel HC, Allen LV, and Popovich NG, Pharmaceutical dosage forms and drug delivery system, 9thedition, Lippincott William & Wilkins, 257-271 (2005).
Chien YW, Rate controlled drug delivery systems, 2nd edition, Marcel Dekker, New York, revised and expanded 2(1) 2005.
Chauhan MJ, Patel SA. A Concise Review on Sustained Drug Delivery System and Its Opportunities. American Journal of PharmTech Research, 2(2), 227-238(2012).
Chugh I, Seth N, Rana AC. Oral sustained release drug delivery system: An overview. International Research Journal of Pharmacy, 3(5), 57-62 (2012)
Bhalla N, Deep A, Goswami M. An Overview on various approaches to oral controlled drug delivery system via Gastroretentive Drug Delivery System. International Research Journal of Pharmacy, 3(4), 128-133 (2016)
Dusane RA, Gaikwad PD, Bankar VH, Pawar SP. A Review on: Sustained release technology. International Journal of Research in Ayurveda and Pharmacy 2(6), 1701-1708 (2015).
Jain NK, Drug delivery system, Methods in molecular biology, Humana Press 3(1) 218(2012)
Wani MS, Controlled Release System-A Review, www.pharmainfo.net/review 6(1) (2008)
Bechgaard H, Nielson GH. Controlled release multiple units and single unit dosage. Drug Dev. & Ind. Pharm. 4(1), 53-67(2002)
Aulton ME, Modified release peroral dosage forms, Pharmaceutics- The science of Dosage form Design, 2nd edition, Churchill Livingstone, New York, 2(1) 290 (2004)
Marroum. PJ Bioavailability/Bioequivalence for Oral controlled release products, Controlled release drug delivery systems: Scientific and Regulatory Issues. Fifth International Symposium on Drug Development, 3 (1), 15–17 (1997).
Banker GS, and Rhodes CT, Sustained and Controlled drug delivery system, Modern Pharmaceutics, 4th edition, Marcel Dekker, New York, 4(1), 212-229 (2002).
Shargel L, Pong SW, and Yu AB, Modified-release drug products, Applied Biopharmaceutics & Pharmacokinetics, 5th Edition, August 312-322 (2004).
Gupta D, Bhatt DC. Studies on enteric coated sustained timed-release tablets of Metronidazole. Journal of Chemical and Pharmaceutical Research, 2(2), 226-232 (2010)
Pogula M, Nazeer S. Extended Release Formulation. International Journal of Pharmacy and Technology. 2(4), 625- 684 (2010).
Modi SA, Gaikwad PD, Bankar VH, Pawar SP. Sustained Release Drug Delivery System: A Review, International Journal of Pharmaceutical Research and Development, 2(1), 147-160 (2011).
Brahmannkar DM, and Jaiswal SB, Controlled released medication, Biopharmaceutics and Pharmacokinetic, 335-346 (1985).
Kumar V, Prajapati SK, Soni GC, Singh M. Sustained release matrix type drug delivery system: A Review. World Journal of Pharmacy and Pharmaceutical Sciences, 1(3), 934-960 (2012)
Wise DL, Venkatraman S, Davar N, and Chester A, An Overview of Controlled Release Systems, Handbook of Pharmaceutical Controlled Release Technology, Marcel Dekker, New York, 431-464 (2000)
Kumar S, Gupta V, Malodia K. Oral Extended Release Drug Delivery System: A Promising Approach. Asian Journal of Pharmacy and Technology, 2(2), 38-43(2012)
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Ho WH, and Lee HLV, Design and fabrication of oral controlled release drug delivery system, Controlled Drug Delivery Fundamentals and Applications, 2ndedition, Marcel Dekker, New York, 2(1), 373-420 (1987)
How to Cite
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.


S-Adenosylmethionine decarboxylase (AdoMetDC) is a pyruvoyl-dependent enzyme that catalyzes an essential step in polyamine biosynthesis. The polyamines are required for cell growth, and the biosynthetic enzymes are targets for antiproliferative drugs. The function of AdoMetDC is regulated by the polyamine-precursor putrescine in a species-specific manner. AdoMetDC from the protozoal parasite Trypanosoma cruzi requires putrescine for maximal enzyme activity, but not for processing to generate the pyruvoyl cofactor. The putrescine-binding site is distant from the active site, suggesting a mechanism of allosteric regulation. To probe the structural basis by which putrescine stimulates T. cruzi AdoMetDC we generated mutations in both the putrescine-binding site and the enzyme active site. The catalytic efficiency of the mutant enzymes, and the binding of the diamidine inhibitors, CGP 48664A and CGP 40215, were analyzed. Putrescine stimulates the kcat/K m for wild-type T. cruzi AdoMetDC by 27-fold, and it stimulates the binding of both inhibitors (IC50s decrease 10-20-fold with putrescine). Unexpectedly CGP 48664A activated the T. cruzi enzyme at low concentrations (0.1-10 μM), while at higher concentrations (>100 μM), or in the presence of putrescine, inhibition was observed. Analysis of the mutant data suggests that this inhibitor binds both the putrescine-binding site and the active site, providing evidence that the putrescine-binding site of the T. cruzi enzyme has broad ligand specificity. Mutagenesis of the active site identified residues that are important for putrescine stimulation of activity (F7 and T245), while none of the active site mutations altered the apparent putrescine-binding constant. Mutations of residues in the putrescine-binding site that resulted in reduced (S111R) and enhanced (F285H) catalytic efficiency were both identified. These data provide evidence for coupling between residues in the putrescine-binding site and the active site, consistent with a mechanism of allosteric regulation.
ASJC Scopus subject areas


Myrcene (Musk Citrus) is the most common and abundant terpene found in cannabis. It's also found in mango, with a flavour profile that's a mix of citrus and musk (eating a mango 45 min. before smoking will increase THC effect). Myrcene has been known for its sedative properties and may be part of the reason cannabis has been used for pain management and is usually recommended as a supplement during cancer treatments.
Limonene (Lemon Citrus) provides a sweet lemon smell. Citrus fruits are loaded with limonene, and it's commonly extracted for use in foods, cleaning products and cosmetics. It is believed to have the potential to improve mood and relaxation, and has been known to help reduce tumor size.
Caryophyllene (Pepper Spice) is found in a variety of edible plants and herbs and smells of pepper and spice, and can also be found in black pepper, cinnamon, cloves, oregano, basil and rosemary. It has long been used in anti-inflammatory topicals and creams and is also thought to reduce anxiety, and is recommended for treating alcohol withdrawal symptoms.
Pinene (Pine Sweet) smells like pine trees, with a hint of rosemary. A relatively common terpene also found in rosemary, orange peels, basil and parsley. It has been studied for a variety of positive effects, including helping with focus and respiratory inflammation.
Terpenes are fragrant oils naturally secreted in cannabis, including other plants, fruits and herbs. They are the organic compounds that give each strain of cannabis its unique aroma, flavour and effects. These oils have been used for centuries in medicine, natural remedies and food. Use search console to filter by terpenes.
California Dreaming (3.5g)
California Dreaming contains our highest grown level of THC. This flower is hand groomed, from seed-to-sale, and grown under natural sunlight with the assistance of LED lights. This indica-dominant flower is derived from flowers known as Hash Plant and Northern Lights. The earthy combination of alpha pinene and beta pinene brings you the sweet smell of pine trees. While pinene is the most widely encountered terpene in nature, underneath the earthy aroma is a hint of spice brought on by beta caryophyllene. California Dreaming is grown in the heart of Niagara's world renown grape and wine country. At Dykstra Greenhouses we take great care in hand grooming our flower to bring you our best product.
Here at Dykstra Landscaping & Greenhouses, we strive to offer you a superior product. Something we are proud to put our name on. With that in mind, we grow our cannabis with the same quality and care as if it were going to our own families. That way you feel comfortable giving it to yours.
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Applied Energy 170 (2016) 130–139
Contents lists available at ScienceDirect
Applied Energy journal homepage: www.elsevier.com/locate/apenergy
A novel phase-change cement composite for thermal energy storage: Fabrication, thermal and mechanical properties He Zhang a, Feng Xing b, Hong-Zhi Cui b, Da-Zhu Chen a,⇑, Xing Ouyang a,⇑, Su-Zhen Xu a, Jia-Xin Wang c, Yi-Tian Huang a, Jian-Dong Zuo a, Jiao-Ning Tang a a b c
Shenzhen Key Laboratory of Special Functional Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering, College of Civil Engineering, Shenzhen University, Shenzhen 518060, China Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
h i g h l i g h t s
g r a p h i c a l a b s t r a c t
A novel flaky graphite-doped phase-
change microcapsule (FGD-MPCM) was prepared. FGD-MPCM has substantial latent heat storage capacity (135.8 J/g). FGD-MPCMs/cement composite is capable of reducing indoor temperature fluctuation. Compressive strength of cement composite with 30% FGD-MPCMs can reach to 14.2 MPa. Time (min)
a r t i c l e
i n f o
Article history: Received 8 November 2015 Received in revised form 16 February 2016 Accepted 17 February 2016
Keywords: Microencapsulated phase-change materials Cement composite Energy storage Thermal stability
a b s t r a c t Facing upon the increasingly severe energy crisis, one of the key issues for reducing the building energy consumption is to pursue high-performance thermal energy storage technologies based on phase-change materials. In this study, a novel cement composite incorporated with flaky graphite-doped microencapsulated phase-change materials (FGD-MPCMs) was developed. Various techniques, such as field emission-scanning electron microscopy (FE-SEM), optical microscopy (OM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to analyse the composite structure and thermal performances. The results indicate that the spherical microcapsules are well dispersed in the cement matrix. When combined within the cement, the thermal stability of the microcapsules was highly improved, and the inclusion of greater amounts of FGD-MPCMs further increased the latent heat of the composite. The mechanical properties of the cement composites were affected with the increase of FGD-MPCMs dosage and the porosity of the composites. In spite of this, the compressive strength and flexural strength of the cement composite with 30% FGD-MPCM could still reach to as high as 14.2 MPa and 4.1 MPa, respectively. Results from the infrared thermography and the model room test suggested that the composite filled with FGDMPCMs is capable of reducing indoor temperature fluctuation and exhibits good potential for application in buildings to enhance energy savings and thermal comfort. Ó 2016 Elsevier Ltd. All rights reserved.
⇑ Corresponding authors. Tel.: +86 755 2653 5133 (D.Z. Chen), +86 755 2653 1629 (X. Ouyang). E-mail addresses: [email protected]
(D.Z. Chen), [email protected]
(X. Ouyang). http://dx.doi.org/10.1016/j.apenergy.2016.02.091 0306-2619/Ó 2016 Elsevier Ltd. All rights reserved.
H. Zhang et al. / Applied Energy 170 (2016) 130–139
1. Introduction With industrial development and population growth, the consumption of resources is increasing, especially that of fossil fuels. Concomitantly, millions of tons of CO2 are emitted into the atmosphere every year because of combustion, which is widely believed to be the main cause of global warming . Among the environmental burdens caused by the excessive use of fossil fuels, 30% of the energy consumption and 1/3 of the greenhouse gas released worldwide are attributed to the building sector . Efforts to increase energy efficiency in the building sector have been intensified to meet heating and cooling requirements [3,4]. Phase-change materials (PCMs)  can store or release large quantities of latent heat via a nearly isothermal phase-change process; therefore, combining construction materials and PCMs is believed to be an efficient way to increase the heat energy storage efficiency of construction elements [5,6]. For instance, Paksoy et al.  reported that 7% of cooling energy and 28% of heating energy was conserved by combining 3.5 kg of PCMs with insulation panels in a test cabin. However, bulk PCMs are not easy to handle in practical applications because of leakage, erosion and super-cooling problems. To solve these problematic limitations, the materials are generally encapsulated with a polymer or inorganic shell before use . Borreguero et al.  and Zhang et al.  incorporated microencapsulated PCMs (MPCMs) into gypsum boards and found that the thermal regulation ability of the boards was enhanced as the amount of microcapsules was increased. Similar results were observed in MPCMs-filled, cement-based composites [11–16] and geopolymer mortar . An effective envelopment of PCMs is important to prevent the leakage of core materials, increase the heat-transfer area and control the volume changes during the phase changes . Many polymers and copolymers, such as polystyrene (PS) [19,20], polyurea (PU) [21–23], poly(methyl methacrylate) (PMMA) [24–26] and melamine–formaldehyde (MF) resin [27,28], are commonly used as shells in MPCMs. However, the poor heat conduction of the pure organic polymer shell limits the response velocity of the microcapsules to the environmental temperature change. More recently, there are growing interests in utilizing polymer–inorganic hybrid shells to improve the thermal conductivity and mechanical performance of phase-change microcapsules. Chang et al.  synthesized microencapsulated n-octadecane with a PMMA-silica hybrid shell via in-situ polymerization and investigated the effect of coupling agents, ageing time and temperature on the thermal properties of the microcapsules. By mixing Cu (II) methacrylate with the oil phase during the fabrication process, Wu et al.  obtained PMMA-SiO2 @ paraffin microcapsules with copper chelation as the ion probe. Yin et al. [31,32] prepared MPCMs with MF resin/SiO2 and a poly(styrene-co-divinylbenzene)/SiO2 shell through Pickering emulsion polymerization and explored the effects of introducing inorganic particles in the MPCMs shell on the mechanical strength, thermal reliability and anti-osmosis performance, which were significantly improved. Moreover, using the same in-situ polymerization method, Chen et al.  incorporated nano-Al2O3 particles into the MPCMs shell and observed an obvious enhancement of the thermal stability of the microcapsules. Graphite is one of excellent thermal conductivity materials. Thermal conductivity coefficient of graphite can reach about 390 W/ (m K), which nearly 1000 times of that of polymer. Due to graphite shape likes a platelet, therefore, less research has addressed flaky graphite-doped, microencapsulated PCMs (FGD-MPCMs) and their applications in the field of building materials as the thermal energy storage carriers. Most researches on enhancement of the thermal stability of the microcapsules only focused on the formation of microcapsules and their thermophysical or mechanical properties, in this work, a
novel cement composite with good thermal energy storage capacity was developed by incorporating self-manufactured, flaky graphite-doped, phase-change paraffin microcapsules via interfacial polycondensation . The structure, phase-change properties, and thermal stabilities of both the microcapsules and the FGD-MPCMs-filled cement composites were well examined. For building thermal energy storage application, both efficiency of the thermal energy storage and the mechanical properties of the cement composite with FGD-MPCMs were evaluated. 2. Experimental 2.1. Materials Paraffin wax (RT28, Rubitherm Technologies Gmbh, Berlin, Germany), which was mainly composed of n-octadecane, was used as the core material of the FGD-MPCMs. 3-Isocyanatomethyl-3,5,5-tri methylcyclohexyl isocyanate (IPDI, Bayer, Taiwan) and diethylene triamine (DETA, Dow Chemical, USA) with purity exceeding 99.5% were used to form the microcapsule shell. Styrene–maleic anhydride copolymer (SMA, ScriptÒ 520, USA) was used as the emulsifier. Flaky graphite powder (800 meshes, Qingdao Tianyuan Graphite Co., Ltd., China) was used as the inorganic filler for the microcapsules. Portland cement powder (PII 42.5R, Guangdong Zhujiang Cement Factory, China) was adopted as the matrix for fabricating the raw cement or cement composite board. Polyacrylic acid (Guangdong Longhu Science and Technology Co., Ltd., China) was used as the water-reducing agent. 2.2. Fabrication 2.2.1. Synthesis of FGD-MPCMs The microencapsulation of paraffin wax doped with flaky graphite powder was achieved through interfacial polycondensation. The fabrication procedure, including the mixing of core materials, emulsification, polymerization, washing and drying, is schematically illustrated in Fig. 1. Paraffin wax, IPDI and flaky graphite were mixed at 50 °C for 30 min to produce the core material with a weight proportion of 30:20:1. Then, the mixture was poured into a 3-ton reaction kettle filled with 1.3 wt% SMA aqueous solution and agitated vigorously at 60 °C for 1 h to generate a stable oil/ water (O/W) emulsion. Subsequently, stoichiometric DETA was added dropwise into the above emulsion to initiate the formation of the polyurea shell. After continuous stirring for three hours, the resultant microcapsules were centrifugally filtered, washed with hot water and dried at room temperature for one week. 2.2.2. Preparation of smart cement composite containing FGD-MPCMs The cement composites were manufactured by mixing Portland cement, FGD-MPCMs and water at room temperature according to the proportions listed in Table 1. For all specimens, the mass ratio of the cement powder and water was 5:2. Compared to the amount of cement powder, the filling contents of FGD-MPCMs in the composites were 10%, 20%, 25% and 30%, and the corresponding composites were named Cement10, Cement20, Cement25 and Cement30, respectively. The fabrication process is illustrated in Fig. 2. The FGD-MPCMs were immersed in water in a 500-ml beaker for 24 h to ensure that they were completely wetted. Then, the mixture was transferred into a metal stirring pot with the cement powder and stirred vigorously for 5 min using a Hobart mixer (Hobart Corporation, Troy, OH, USA). During this step, the remaining water was calculated, and a very small amount of waterreducing agent was added. The resulting slurry was poured into the moulds and kept for one day to form board-like or cylindrical cement samples. Finally, the above samples were inserted into a curing chamber at constant temperature and humidity (Dongxing
H. Zhang et al. / Applied Energy 170 (2016) 130–139
Washing & Drying
Fig. 1. Schematic synthesis of the FGD-MPCMs. Table 1 Descriptions of the raw cement and cement composites filled with FGD-MPCMs. Samples
Cement powders (g)
Water reducing agent (g)
Raw cement Cement10 Cement20 Cement25 Cement30
500 500 500 500 500
1250 1250 1250 1250 1250
0 125 250 312 375
0 0 2.8 3.7 4.8
Building Material Co., Ltd., China) and placed into water for fast curing at 50 °C for three days.
atmosphere. The temperature scanning range was from 10 to 50 °C.
2.3.3. Thermogravimetric analysis (TGA) TGA of the FGD-MPCMs and cement composites were performed under a nitrogen atmosphere using a TA Q50 thermal gravimetric analyser. For each test, the sample was first heated from 30 to 120 °C at a rate of 20 °C/min and was kept at 120 °C for 20 min to remove the adsorbed water. The temperature was then quickly decreased to 30 °C and increased to 500 °C at a heating rate of 10 °C/min.
2.3.1. Structures of the FGD-MPCMs and cement composites The morphologies of the FGD-MPCMs and their dispersion in the cement composites were examined using a Hitachi Su-70 field emission-scanning electron microscope (FE-SEM) at an accelerating voltage of 1.0 kV. The samples of FGD-MPCMs and the fractured surfaces of the composites were sprayed with gold prior to observation. A Mshot MP41 optical microscope (OM) equipped with a MC 50 digital imaging system (Guangzhou Micro-shot Technology Co., Ltd., China) was used to observe the microstructures of the microcapsules. The crystalline phases of the FGD-MPCMs were analysed by an X-ray diffractometer (XRD, Bruker D8) with Cu Ka radiation (k = 0.154 nm) with operating conditions of 40 kV and 200 mA. The XRD pattern was recorded in the 2h range from 10° to 80° with a scanning rate of 3°/min.
2.3.4. Infrared thermography To determine the thermo-regulating performance of the cement composite, infrared thermography was conducted with an infrared thermal imager (FLIR SC655). A round composite disk containing 20% FGD-MPCMs with a diameter of 25 mm and a thickness of 3 mm was prepared in a cylindrical mould. A raw cement disk without FGD-MPCMs was also fabricated as a reference. Both samples were cooled to 3 °C in advance and placed onto a hot stage maintained at a constant temperature of 60 °C. To prevent the sample’s temperature from rising too quickly, a cylindrical PTFE disk (U 25 mm) with a thickness of 5 mm was placed between the hot plate and the test sample. The microscope lens was kept
2.3.2. Differential scanning calorimetry (DSC) The phase-change properties of the FGD-MPCMs and cement composites were analysed using a TA Q200 differential scanning calorimeter at a heating/cooling rate of 5 °C/min in a nitrogen
Water reducing agent
Wetting of FGD-MPCMs
Molding & curing
Cement composite with FGD-MPCMs
Fig. 2. Schematic fabrication of the FGD-MPCMs-filled cement composite.
H. Zhang et al. / Applied Energy 170 (2016) 130–139
Cement composite wall
Raw cement wall Model room without test wall
Model room with composite wall
Thermocouple Data logger
Computer recording system
Heat source Test setup with model room
Installation of model room
Fig. 3. Schematic diagram of the setup used to evaluate the thermal regulation capacity of the FGD-MPCMs-filled cement composite.
at 25 cm from the upper surface of the sample during the test. The infrared thermal images of both the composite and control were taken at different times from 3 to 40 °C and analysed using FLIR Researcher IR software. 2.3.5. Evaluation of the energy storage capacity of the cement composite The energy storage capacity of the cement composite was evaluated using a self-made setup  equipped with a small test room, a thermal channel, a heat source and a temperaturerecording system, as shown in Fig. 3. The cubical test room is composed of six walls: one testing cement panel with/without FGD-MPCMs and five other walls made of polystyrene foam to provide a heat-insulating environment. The room is connected to a 300mm-long cylindrical heat channel made of polyvinyl chloride with reflective paper to create a uniform and stable temperature field by a connecting wooden board (500 500 15 mm3) with an opening of 200 200 15 mm3. The cement composite board with 20% FGD-MPCMs and dimensions of 200 200 40 mm3 was inserted into the test room opening as a wall. Then, after installing two contacts of a K-type thermocouple (resolution ± 0.3 °C), the small room was placed into a wooden box with the test wall close to the heat channel. The thermal-electric couple contact attached at the outer surface of the cement composite wall was used to measure the wall temperature, and the one inserted into the centre of the test room was used to examine the ‘‘indoor” temperature. A 500-W lamp was used to supplement the heat source and placed at 200 mm from the heat channel. In this test, the test wall was heated for 1 h and then cooled naturally for 40 min. For comparison, a raw cement board with the same size was measured using the same experimental procedure to serve as a control.
2.3.6. Porosity measurement Mercury intrusion porosimetry (MIP) has proven to be a powerful technique to characterize porous materials with pore sizes ranging in several orders of magnitude . In this study, MIP tests of the cement composites were conducted using an AutoPore IV 9500 (Micrometrics) porosimeter capable of producing up to 33 103 psia.
2.3.7. Mechanical properties of cement composites The mechanical properties of the cement composite with different dosage of FGD-MPCMs were evaluated by studying its compressive strength and flexural strength at the age of three days in this research. The compressive strength (40-mm cube) and flexural strength (40 mm 40 mm 160 mm prism) of the hardened cement paste was determined at the age of 3 days in accordance with GB/T 17671-1999 (method of testing cements-determination of strength) [Method of Testing Cements-Determination of Strength (ISO); GB/T 17671-1999; Chinese National Standard: Beijing, China, 1999]. The loading rates for compressive and flexural strength were 2400 ± 200 N/s and 50 ± 10 N/s. The test specimens with a size of 40 mm 40 mm 160 mm were fast cured for 3 days in a curing room at a temperature of 50 ± 1 °C and a relative humidity of 99%. The loading rate for the flexural and compressive strength were 50 ± 10 N/s and 2400 ± 200 N/s, respectively. Before doing the compressive strength test, the dimensions of the sample were measured, and the mass of the sample was recorded using an electronic balance with a ±0.1 g error. The density of each sample was then calculated, which represented the average of three samples.
H. Zhang et al. / Applied Energy 170 (2016) 130–139
200 μm Fig. 4. FE-SEM photos of (a) FGD-MPCMs and (b) their cross-sections; (c) OM image and (d) XRD pattern of FGD-MPCMs.
3. Results and discussion
3.3. Phase-change properties
3.1. Microstructure of FGD-MPCMs
Fig. 6 displays the DSC results of phase-change behaviours of the FGD-MPCMs and cement composites containing different amounts of FGD-MPCMs. The melting and crystallization parameters of the FGD-MPCMs and cement composites and the pure PCMs are listed in Table 2. In the tested temperature range, no thermal effect was found for the raw cement, suggesting that the endo-/ exo-thermal peaks for the cement composites could be attributed to the FGD-MPCMs. The whole melting process of the composites falls in the temperature range of approximately 18–33 °C. The melting points (Tm) for the cement composites containing 20%, 25% and 30% microcapsules were 26.76, 27.87 and 28.52 °C, respectively, which are the comfortable temperatures for human body. The solidification of PCMs incorporated in the cement composite occurred within the temperature range of approximately 28–10 °C, and compared to the freezing curve of FGD-MPCMs, a visible left-shift of the crystallization peaks was observed for the cement composite filled with FGD-MPCMs. As confirmed by the XRD pattern above (Fig. 4d), the two crystallization forms of a- and b-crystals of n-octadecane were also noticeable in the cooling DSC curves as two corresponding exothermic peaks . The formation of a-crystals resulted from the heterogeneously nucleated liquid-rotator transition for which the microcapsules and graphite particles acted as nucleating agents. The b-crystals were formed via the homogeneous nucleation mechanism of liquid transition. The latent heats of fusion and solidification were 248.80 and 249.90 J/g for pure PCMs and 135.80 and 137.60 J/g for FGDMPCMs, respectively. According to the equation below , the encapsulation efficiency was 54.82%. Table 2 shows that the latent heats of phase change for the composite increased monotonously as the FGD-MPCMs content increased. In the case of cement composite containing 30% FGD-MPCMs, the values for melting (DHm) and freezing (DHf) processes reached to 34.02 and 33.85 J/g, respectively. Therefore, the incorporation of FGD-MPCMs
The morphology and microstructure of the FGD-MPCMs are shown in Fig. 4a–d. The microcapsules have a spherical profile with many surface wrinkles attributed to the reduced volume of the paraffin wax during the phase change from the melting state to the crystal state . The shell thickness of the microcapsules is approximately 7.5 lm (Fig. 4b). In the optical microscope micrographs (Fig. 4c), the black graphite platelets are well dispersed in the microcapsules, as shown by the different contrast between the graphite and shell polymer (PU). The existence of flaky graphite was further confirmed by the XRD patterns of the FGD-MPCMs (Fig. 4d). The strong peak at 2h = 26.48° was assigned to the characteristic diffraction peak of the (0 0 2) plane of graphite. The reflection of the (0 0 4) plane of graphite was observed at 2h of 54.60° . Moreover, the characteristic peaks for the phasechange paraffin, which mainly consisted of n-octadecane, also appeared in the pattern. The peaks at 2h = 24.71° and 44.43° correspond to the diffractions of the (1 1 1) plane of the a-crystal phase and the (2 0 5) plane of the b-crystal phase, respectively . 3.2. Microstructure of FGD-MPCMs-filled cement composites Fig. 5a–c presents the FE-SEM photos of cement composites containing 10%, 20% and 30% FGD-MPCMs. The majority of the microcapsules were in good condition and were uniformly distributed in the cement matrix. Concave nests and some fractured microcapsules resulted from microcapsule pull-out during the fabrication of the cross-sectional specimen were observed. Fig. 5d shows good interfacial bonding between microcapsules and the cement matrix. The wrinkles formed on the microcapsule surface provide substantial points for cement attachment and fixation, favouring the formation of an embedded interfacial bonding mode.
H. Zhang et al. / Applied Energy 170 (2016) 130–139
Fig. 5. FE-SEM photos of cement composites containing various amounts of FGD-MPCMs: (a) 10%, (b) 20%, (c) 30% and (d) magnified image of a microcapsule buried in the cement matrix.
improved the thermal energy storage efficiency of the cementbased building materials.
DHm;FGD-MPCMs þ DHf ;FGD-MPCMs 100% DHm;PCM þ DHf ;PCM
3.4. Thermal stability Thermal degradation curves of the FGD-MPCMs and cement composites containing various amounts of FGD-MPCMs are presented in Fig. 7, and the characteristic temperatures are listed in Table 3. Fig. 7 shows clear two-step weight loss processes for both FGD-MPCMs and their filled cement composites over the heating range of 30–500 °C. In the case of the raw cement material, only a weak decreasing trend of weight loss was observed during the whole heating process because of the free-water evaporation, the bound water and the decomposition of ettringite and portlandite . Hence, the rapid decrease in the weight loss of the cement composites was ascribed to FGD-MPCMs degradation. When greater amounts of FGD-MPCMs were used, the weight loss of the composite material was also greater. However, increasing the FGD-MPCMs content did not change the characteristic temperatures of the cement composites. The first decomposition stage of microcapsules is caused by the evaporation and decomposition of PCMs in the microcapsules , and for pure FGD-MPCMs, the starting decomposition temperature (T1,o), the end temperature (T1,e) and the temperature of the maximum degradation rate (T1,m) are 272.05, 283.31 and 278.18 °C, respectively. In contrast, the corresponding temperatures of T1,o, T1,e and T1,m (listed in Table 3) were found with delays of 46.56, 56.08 and 53.05 °C for the composite with 10% FGD-MPCMs; 48.52, 58.35 and 54.37 °C for the composite with 20% FGD-MPCMs; and 46.34, 53.48 and 52.17 °C for the composite with 30% FGD-MPCMs. The decomposition of the shell materials of the microcapsules occurs during the second stage of rapid degradation, when the composites show a similar delay in the characteristic decomposition
temperatures compared to the pure microcapsules. For instance, in the case of the composite with 10% FGD-MPCMs, the delayed temperatures of T2,o, T2,e and T2,m were 81.93, 68.48 and 75.59 °C, respectively, whereas for the composite with 30% FGD-MPCMs, they were 83.56, 67.68 and 75.34 °C, respectively. These results indicate that when incorporated in the composite, the thermal stability of the microcapsules was enhanced by the surrounding inorganic matrix, which is believed to favour improving the durability of the smart cement materials able to store energy when exposed to severe environmental conditions (i.e., high temperature). 3.5. Infrared thermal imaging analysis The surface temperature distribution on the cement disks with/ without FGD-MPCMs at various times was measured by infrared thermography and is shown in Fig. 8. The increase in the temperature of the cement composite was slower than that of the raw cement disk. The temperature differences between the raw cement and the composite at various times were calculated and are illustrated in Fig. 9. When heated for 17 min, both the temperature at the test point (Sp1) and the average surface temperature showed maximum differences (i.e., 5.0 °C at Sp1 and 4.9 °C for the average value), whereas before and after this time, the differences showed a decreasing trend in the opposite direction. During the heating process, the temperature change on the surface of the disk without FGD-MPCMs depends only on the sensible heat of the cement, whereas for the cement composite containing FGD-MPCMs, the latent heat of the PCMs provides much higher storage density  and thus shows a less marked heating effect than the raw cement without FGD-MPCMs . Furthermore, when the cement composite was heated for 17 min, the encapsulated PCMs within the composite reached their melting point, and the cement composite exhibits maximum heat absorption during the melting process. These results indicate that the incorporation of FGD-MPCMs allows the cement composite to delay the temperature change.
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Fig. 7. TGA curves of FGD-MPCMs and the cement composites containing various amounts of FGD-MPCMs. The inner plot is a magnification of the first degradation step of the cement composites.
Table 3 Thermal stabilities of the raw cement, FGD-MPCMs and cement composites containing various amounts of FGD-MPCMs. Step 1
Raw cement Cement10 Cement20 Cement25 Cement30 FGD-MPCMs
Fig. 6. DSC thermograms of FGD-MPCMs and the cement composites containing various amounts of FGD-MPCMs during (a) melting and (b) freezing.
Table 2 Thermal properties of the raw cement, FGD-MPCMs and cement composites containing various amounts of FGD-MPCMs. Melting process
Raw cement Cement20 Cement25 Cement30 FGD-MPCMs Pure PCMs
– 26.76 27.87 28.52 30.58 28.32
– 14.57 22.35 34.02 135.80 248.80
– 21.85 21.45 21.02 21.49 –
– 18.87 19.44 18.76 16.20 24.43
– 12.71 23.25 33.85 137.60 249.90
3.6. Evaluation of the thermal energy storage capacity in a model room To further evaluate the thermo-regulating capacity, the composite board was used as a wall in a self-made model room, as shown in Fig. 3. The temperature variations at the room centre and the walls with or without FGD-MPCMs during the test period, which consisted of 60-min heating and subsequent 40-min cooling, are plotted in Fig. 10. When exposed to the heat source, a visible delay in the temperature response was observed for the room with the FGD-MPCMs-filled wall compared to the control with raw cement wall. In the initial heating stage (i.e., from the start to 17 min for the test wall and 8.5 min for the room centre), the temperature was less than 18 °C, and the PCM phase change did not occur. Because of the lower thermal conductivity of microcapsules compared to the cement matrix, the temperatures of the room with the composite wall were slightly lower than those of the control room. As the process continued, the involved PCMs
147.20 318.61 320.57 319.35 318.39 272.05
229.49 339.39 341.66 338.59 336.79 283.31
183.07 331.23 332.55 331.23 330.35 278.18
432.66 415.50 413.00 414.80 417.13 333.57
480.29 438.54 447.41 436.32 437.74 370.06
458.43 427.37 427.24 425.28 427.12 351.78
Note: T1,o and T1,e were determined from the cross-point of two tangent lines at related bending locations during the first rapid decomposition. T1,m was determined as the temperature corresponding to the peak on the derivative curve of the decomposition. Similar methods were adopted to obtain T2,o, T2,e and T2,m.
(paraffin) began to melt and absorb the environmental heat with a larger latent heat mode , and the temperature differences between the room with the composite wall and the control room increased. When heated for 40 min, the temperature differences were 7.54 °C at the wall and 3.60 °C at the room centre. Twenty minutes later, the differences were maximized: compared with the control room, the temperatures of the room with the composite wall decreased by 13.10 °C at the wall and by 6.22 °C at the room centre. Correspondingly, the temperature curves of the room with the composite wall were right shifted and showed a wide, downward peak resulting from the phase change of the core materials. Similar temperature regulation capacity of the FGD-MPCMs-filled board was found in the cooling process. Within the tested time range of this study, the temperatures of the room containing the composite wall decreased more slowly than those of the control room. When cooled naturally for 20 min, the temperatures of the room with the composite wall remained 5.88 °C and 2.32 °C lower at the wall and room centre, respectively, than those of the control room. These results indicate that the FGD-MPCMs reduced the indoor temperature fluctuations and thus exhibited good application potential in buildings to achieve energy storage and thermal comfort. 3.7. Porosity, density and mechanical properties of the cement composites Porosities and densities of the cement composites with different dosage of FGD-MPCMs are listed in Table 4. From Table 4, it
H. Zhang et al. / Applied Energy 170 (2016) 130–139
Fig. 8. Infrared thermography images of the cement disks with and without FGD-MPCMs heated for different times. The maximum, minimum and average temperatures and the temperatures determined at the marked point (Sp1) are presented under each thermal image.
Fig. 9. Temperature differences between the raw cement disk and the FGDMPCMs-filled cement disk as a function of time.
can be known that the density of cement composite decreased with the increase of FGD-MPCMs dosage. The reason for this is that the density of PCM is lower than that of cement paste. The decrease of density of the cement composite in percentages are approximately proportional to the FGD-MPCMs dosages in the cement composites. In regard to the porosity of cement composite, with FGD-MPCMs dosage increase, it increased from 3.67% to 8.49%. Compared with the FGD-MPCMs dosage increase, the percentage increase in the porosity of cement composite is dramatical. The reason for this phenomenon maybe the increasing FGD-MPCMs in the cement composites would lead to a greater volume of interfacial transition zone (ITZ) between FGD-MPCM and the matrix. Compared with the matrix of cement paste, the ITZ has a high porosity [40,41]. The results of the compressive strength and flexural strength of hardened cement composites with different mass percentages of FGD-MPCMs are presented in Fig. 11. As shown in Fig. 11, the compressive strength and flexural strength of cement composites decreased with the increase in the mass percentage of FGD-MPCMs. The decreases in compressive strength and flexural strength of the cement composites are due to the presence of weaker MPCMs in compression and increasing porosities of the samples. When the mass percentages of FGD-MPCMs are 10%, 20%, 25%, and 30%, the reductions in compressive strength with respect to control cement material are 28.2%, 41.1%, 47.8%, and 58.4%, respectively. However, despite the negative effect of FGDMPCMs on the mechanical strength of the cement composites observed in this study, the compressive strength and flexural strength of cement composite with 30% FGD-MPCMs can reach to
Fig. 10. Comparison of the thermal regulation performance between the raw cement and the composite using a model room. Temperature variations (a) at the test wall and (b) at the room centre.
as high as 14.2 MPa and 4.1 MPa, respectively, according to BS EN 998-2:2002 (Specification for mortar for masonry – Part 2: Masonry mortar), which satisfies the requirements for building application. In further study of the cement composite with FGDMPCMs, the mechanical strength and bonding between FGDMPCMs and the matrix can be enhanced by adding superfine mineral admixture and/or increasing the surface roughness of FGDMPCMs.
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Table 4 Porosities and densities of the cement composites. FGDMPCMs percentage (%)
Density of cement composite (kg/ m3)
Density decrease percentage
Porosity of cement composite (%)
Porosity increase percentage
0 10 20 25 30
2210.4 2007.3 1804.9 1703.5 1601.7
0.0 9.19 18.3 22.9 27.5
3.67 4.91 6.95 7.85 8.49
0.0 33.8 89.4 113.9 131.3
Compressive strength (MPa)
35 30 25 20 15 10 5
Content of FGD-MPCMs (%) 7
The authors would like to acknowledge the support of the National Natural Science Foundation of China (51173109, 51308345) and the Guangdong Province Natural Science Foundation (2014A030313561). References
Flexural strength (MPa)
(3) A novel cement composite with good thermal energy storage ability was developed by using FGD-MPCMs. The FGDMPCMs were well distributed in the matrix, and good interfacial bonding was achieved. (4) Integrating the board with 20% FGD-MPCMs into the wall of the room model, the maximum temperatures of the cement composite walls and the maximum indoor temperatures of the test rooms were decreased obviously and the differences were as high as 13.1 °C and 6.22 °C, respectively. The infrared thermography test results also confirmed that the cement composite with FGD-MPCMs can lower the temperature effectively. These results indicated that the FGDMPCMs-filled cement composite has great potential applications in buildings to achieve high thermal energy-saving capacity. (5) The compressive and flexural strength of the cement composites both exhibited a decreasing tendency with an increase in the dosage of FGD-MPCMs. Cement composite with 30% FGD-MPCMs reduced the flexural strength by 34.9% and the compressive strength by 58.4%. This phenomenon can be attributed to the presence of weaker MPCMs relative to hard cement in compression and increasing porosity of the cement composites.
5 4 3 2 1 0 0
Content of FGD-MPCMs (%) Fig. 11. The compressive strength (a) and flexural strength (b) of raw cement and cement composites with different mass percentages of FGD-MPCMs.
4. Conclusions From the experimental investigation, the following conclusions can be drawn: (1) An innovative microencapsulated phase change material (FGD-MPCM) with polymer–inorganic hybrid shell, was prepared in this study. Flaky graphite was served as an inorganic hybrid material with high thermal conductivity. (2) The SEM, DSC and TGA test results showed that the FGDMPCMs possess a high quality encapsulation, about 55% encapsulation efficiency and good thermal reliability. The FGD-MPCMs have a melting temperature of 30.58 °C and latent heat of 135.8 J/g.
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H. Zhang et al. / Applied Energy 170 (2016) 130–139  Ramakrishnan S, Sanjayan J, Wang X, Alam M, Wilson J. A novel paraffin/expanded perlite composite phase change material for prevention of PCM leakage in cementitious composites. Appl Energy 2015;157:85–94.  Shadnia R, Zhang LY, Li PW. Experimental study of geopolymer mortar with incorporated PCM. Constr Build Mater 2015;84:95–102.  Hawlader MNA, Uddin MS, Khin MM. Microencapsulated PCM thermal-energy storage system. Appl Energy 2003;74:195–202.  Fu ZY, Pei GL, Shan XH. Preparation and performance of n-octadecane/PS core– shell structure microPCMs. Text Bioeng Inf Symp Proc 2011:323–7.  Mochane MJ, Luyt AS. Preparation and properties of polystyrene encapsulated paraffin wax as possible phase change material in a polypropylene matrix. Thermochim Acta 2012;544:63–70.  Ma YH, Chu XD, Tang GY, Yao YW. Adjusting phase change temperature of microcapsules by regulating their core compositions. Mater Lett 2012;82: 39–41.  Wu Q, Zhao D, Jiao X, Zhang Y, Shea KJ, Lu XH, et al. Preparation, properties, and supercooling prevention of phase change material n-octadecane microcapsules with peppermint fragrance scent. Ind Eng Chem Res 2015;54: 8130–6.  Zhang HZ, Wang XD. Synthesis and properties of microencapsulated noctadecane with polyurea shells containing different soft segments for heat energy storage and thermal regulation. Sol Energy Mater Sol Cells 2009;93: 1366–76.  Al-Shannaq R, Farid M, Al-Muhtaseb S, Kurdi J. Emulsion stability and crosslinking of PMMA microcapsules containing phase change materials. Sol Energy Mater Sol Cells 2015;132:311–8.  De Santis R, Ambrogi V, Carfagna C, Ambrosio L, Nicolais L. Effect of microencapsulated phase change materials on the thermo-mechanical properties of poly(methyl-methacrylate) based biomaterials. J Mater Sci – Mater Med 2006;17:1219–26.  Giro-Paloma J, Barreneche C, Delgado M, Martinez M, Fernandez AI, Cabeza LF. Physicochemical and thermal study of a MPCM of PMMA shell and paraffin wax as a core. Energy Proc 2014;48:347–54.  Su JF, Wang LX, Ren L. Fabrication and thermal properties of MicroPCMs: used melamine–formaldehyde resin as shell material. J Appl Polym Sci 2006;101: 1522–8.  Konuklu Y, Unal M, Paksoy HO. Microencapsulation of caprylic acid with different wall materials as phase change material for thermal energy storage. Sol Energy Mater Sol Cells 2014;120:536–42.
 Chang CC, Tsai YL, Chiu JJ, Chen H. Preparation of phase change materials microcapsules by using PMMA network-silica hybrid shell via sol–gel process. J Appl Polym Sci 2009;112:1850–7.  Wu XL, Wang YH, Zhu PL, Sun R, Yu SH, Du RX. Using UV–vis spectrum to investigate the phase transition process of PMMA-SiO2@paraffin microcapsules with copper-chelating as the ion probe. Mater Lett 2011;65: 705–7.  Yin DZ, Ma L, Liu JJ, Zhang QY. Pickering emulsion: a novel template for microencapsulated phase change materials with polymer–silica hybrid shell. Energy 2014;64:575–81.  Yin DZ, Liu H, Ma L, Zhang QY. Fabrication and performance of microencapsulated phase change materials with hybrid shell by in situ polymerization in Pickering emulsion. Polym Adv Technol 2015;26:613–9.  Chen L, Zhang LQ, Tang RF, Lu YL. Synthesis and thermal properties of phasechange microcapsules incorporated with nano alumina particles in the shell. J Appl Polym Sci 2012;124:689–98.  Chen L, Xu LL, Shang HB, Zhang ZB. Microencapsulation of butyl stearate as a phase change material by interfacial polycondensation in a polyurea system. Energy Convers Manage 2009;50:723–9.  Pastorino D, Canal C, Ginebra M-P. Multiple characterization study on porosity and pore structure of calcium phosphate cements. Acta Biomater 2015;28:205–14.  Shan XL, Wang JP, Zhang XX, Wang XC. Formaldehyde-free and thermal resistant microcapsules containing n-octadecane. Thermochim Acta 2009;494: 104–9.  Takamura T, Endo K, Fu L, Wu Y, Lee KJ, Matsumoto T. Identification of nanosized holes by TEM in the graphene layer of graphite and the high rate discharge capability of Li-ion battery anodes. Electrochim Acta 2007;53:1055–61.  Qiu XL, Song GL, Chu XD, Li XZ, Tang GY. Microencapsulated n-alkane with p (n-butyl methacrylate-co-methacrylic acid) shell as phase change materials for thermal energy storage. Sol Energy 2013;91:212–20.  Metalssi OO, Ait-Mokhtar A, Ruot B. Influence of cellulose ether on hydration and carbonation kinetics of mortars. Cem Concr Compos 2014;49:20–5.  Xu W, Chen H, Duan Q, Chen W. Strategy for interfacial overlapping degree in multiphase materials with complex convex particles. Powder Technol 2015;283:455–61.  Sicat E, Gong F, Ueda T, Zhang D. Experimental investigation of the deformational behavior of the interfacial transition zone (ITZ) in concrete during freezing and thawing cycles. Constr Build Mater 2014;65:122–31.


Plastics and Polymers: Plasticizers BASF and Sinopec Team Up for Chinese Plasticizer Production
A union of giants: Chemical heavyweight BASF and Chinese petrochemical giant Sinopec plan a further cooperation for a new world-scale isononanol (INA) plant in Maoming, China. With this investment in plasticizers, the two partners could significantly increase their footprint in China's rubber and polymers business, industry experts believe.
Shenzhen/PR China; Ludwigshafen/Germany – “As the Chinese market continues its rapid growth with booming demand for plasticizers, the INA investment in Maoming serves the increasing demand for next generation plasticizers,” said Dr. Albert Heuser, President of BASF Asia Pacific. Under the terms of the MoU, the two parties will evaluate the technical, commercial and economic viability of jointly owning and operating a world-scale facility for the production of INA under a 50-50 joint venture agreement. A financial scope will be determined after the completion of a joint feasibility study by the end of 2012.
Plasticizers: Versatile Raw Material for Chinese Plastics and Polymers Industry
INA is used as the feedstock for the production of next generation plasticizers, like diisononyl phthalate (DINP) and non-phthalate plasticizer Hexamoll DINCH. Plasticizers like these are widely used for rubbers and polymers in applications such as automotive, wires and cables, flooring, building and construction.
“After many years of successful cooperation with Sinopec, this project builds on our strong partnership and offers an exciting opportunity for BASF in China. Maoming provides excellent integration possibilities into the refinery structure, which will contribute further to the overall environmental and economic efficiency of the project,” added Dr. Hreuser. The memorandum was signed by Dr. Albert Heuser, President BASF Asia Pacific and Dr. Yu Xizhi, President of Sinopec Maoming, on July 30 in Shenzhen, China.
“Cooperation Highlights the Success of international Partnerships”
Dr. Yu Xizhi, President of Sinopec Maoming commented, “This cooperation not only builds on the valued relationship Sinopec already holds with BASF, but also goes to highlight the success of Sinopec’s international partnerships. We are confident that this development will provide an even broader range of chemical products to the South China region, as well as across the country, contributing to a sustainable future.” Both companies already cooperate on a 50%50 joint venture for BASF-YPC, a world scale petrochemical production in Nanjing.


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Your body's typical osmotic stress, and that is isotonic, allows a consistent servicing of physique tissues. To ensure that a material to get absorbed and used in your body's metabolism, it has to more info be in an isotonic condition.
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In general, the exam includes checking a candidate’s vital signs, weight, temperature, pulse, and blood pressure. It may also include specific tests such as drug and alcohol testing, physical ability and stamina testing, and psychological testing.
Do they drug test during physicals?
The pre-employment physical exam also includes drug test screening. They are categorized into following classes such as: Hair drug and alcohol screening. Sweat drug screening.
What do they check for in a physical urine test?
Overview. A urinalysis is a test of your urine. It’s used to detect and manage a wide range of disorders, such as urinary tract infections, kidney disease and diabetes. A urinalysis involves checking the appearance, concentration and content of urine.
Do urine tests show drugs?
Urine drug testing detects evidence of recent drug use or misuse in a sample of urine. Testing can detect illegal or prohibited drug use, prescription medications, over-the-counter medicines, and legal substances such as alcohol and tobacco.
Does annual physical include urine test?
A urinalysis is a lab test that is often part of your annual physical with your Riverside Health System primary care provider.
What are 4 types of tests done on urine?
Red blood cell urine test. Glucose urine test. Protein urine test. Urine pH level test.
What should you not do before a urine test?
– Avoid alcohol, coffee, tea, tobacco and strenuous exercise for 24 hours prior to collection and up to collection time. – Do not consume avocados, bananas, eggplant, pineapples, plums, tomatoes or walnuts for 48 hours before the test.
Why do doctors take urine samples for physicals?
Urinalysis used to be routine during check-ups, typically to test for traces of blood, protein, or sugar. This helped to identify people with hidden kidney disease or diabetes. Currently, most diseases that we can detect with urinalysis can be diagnosed much earlier with blood tests.
How long will drugs show in a urine test?
Opioids like heroin and oxycodone are detectable for between 1 and 3 days after last use. Stimulants including cocaine, meth, and ADHD medications are detectable for about 2 or 3 days. Benzodiazepines and MDMA generally flag a urine test for up to 4 days after last dose.
How long can Labs detect drugs in urine?
In general, the detection time is longest in hair, followed by urine and oral fluid. Drugs in hair may be detectable for up to 90 days, whereas drugs in urine are generally detectable for one to seven days (or longer in chronic users) and in oral fluid from five to 48 hours.
How far back does a urine drug test go?
Drug testing specimen types Illicit substances are detectable for only five to 10 days in urine; whereas, hair drug tests can detect drug or alcohol use for up to 90 days. Blood testing is very accurate, but costly and invasive. It does have a shorter detection period (minutes to hours), however.
Do you have to take your clothes off for a physical?
For annual physicals, patients will be gowned, so they shouldn’t wear constricting, hard-to-remove clothing.
What can make you fail a pre-employment physical?
Failing a pre-employment physical or HPE can happen for a number of reasons, though often failing a drug or alcohol test can be the reason a candidate does not pass. This is particularly common for jobs involving driving or operating heavy machinery where sobriety is of paramount importance.
How do I prepare for a pre-employment physical?
- Paperwork you’ve given them detailing what services they need, including lab orders if necessary.
- Aids they might need such as glasses, hearing aids, etc.
- Valid form of ID such as a driver’s license, state or federal ID, or an employer-issued badge.
Which of the following is not included in the physical examination of urine?
Which of the following is NOT included in the physical examination of urine? Noting excess glucose. Which of the following is the most important technique to stress when instructing the patient in collecting a clean-catch, midstream specimen to avoid contamination?
Can I drink water before urine test?
Before your test, make sure to drink plenty of water so you can give an adequate urine sample. However, drinking excessive amounts of water may cause inaccurate results. One or two extra glasses of fluid, which can include juice or milk if your diet allows, is all you need the day of the test.
Why do I have white pee?
Cloudy or milky urine is a sign of a urinary tract infection, which may also cause a bad smell. Milky urine may also be caused by bacteria, crystals, fat, white or red blood cells, or mucus in the urine.
When is the best time to do a urine sample?
Within two hours is best. If possible, collect samples in the morning Mon-Friday so the sample can be taken to the surgery before 11am.
How long does one smoke session stay in your system?
It showed: For someone smoking cannabis for the first time, tests may detect it for about 3 days. In someone who smokes cannabis three or four times per week, the detection window is 5–7 days. For people who smoke cannabis once a day or more, tests may detect it in their system for 30 days or longer.
How do I prepare for a urine test?
- Before the test, don’t eat foods that can change the colour of your urine. Examples of these include blackberries, beets, and rhubarb.
- Don’t do heavy exercise before the test.
- Tell your doctor ALL the medicines and natural health products you take.
What do you say when you fail a drug test?
Common excuses for failing a drug test It must have been something I ate. I kissed my boyfriend after he smoked a joint. My dentist gave me something strong for a sore tooth. I ate a lot of poppy seed muffins for breakfast.
Can a lab tell if it’s synthetic urine?
Yes, Quest can detect synthetic urine using specimen validity testing, a screening that determines if a specimen is human urine. All urine drug test specimens coming into Quest Diagnostics facilities include specimen validity testing as part of the drug testing process.
How far back does a 10 panel urine test go?
Some 10-panel drug tests are designed to test for drugs in hair samples. The drugs can be detected for up to 90 days when a hair sample is used. What this means is that the drug being tested for might no longer be able to be detected after these periods have passed.
What drugs do employers test for in urine?
Typical drugs screened in a pre-employment urine drug test include marijuana, cocaine, amphetamines/methamphetamines, PCP, and opioids, with the option for employers to test for many additional substances.
What is the most common drug test used by employers?
1. Urine Tests. Urine tests are the most common type of pre-employment drug test used by employers in the U.S. However, they also have a shorter detection window than the other types of drug tests.


Diamond History Have you ever wondered, how old really, are the diamonds we see around us? Diamonds are aptly called as messengers from the deep earth. Scientists having been studying them closely to understand what goes on into the otherwise inaccessible depths from which they come. But the messages are often hard to read.
Recently, a team has come up with a way to determine the age of diamonds with inclusions, and the chemistry of their parent material. The research has allowed them to map out geologic events going back more than a billion years – which is of huge significance not only in the study of diamonds, but of planetary evolution.
Nature of Diamonds
Gem-quality diamonds are grid-like structures of nearly pure carbon. This purity (being made of just one element) gives them them their brilliance; but it also means they carry very little information about their age and origin.
However, some lower-grade diamonds contain imperfections in the form of tiny pockets of liquid – essentially what’s left of the more complex fluids from which the diamond crystals evolved.
By analyzing these fluid filled imperfections, the scientists through a new study worked out the times when different diamonds formed, and the shifting chemical conditions around them.
What Do We Know So Far On Diamonds?
Most diamonds are believed to have formed some 150 to 200 kilometers under the surface, in relatively cool masses of rock beneath the continents. This may have happened as far back as 3.5 billion years, and probably continues even today at some rate. Occasionally, these diamonds in the making or completed are carried upward by powerful, volcanic eruptions called kimberlites.
Much of what we know about diamonds comes from lab experiments, and studies of other minerals and rocks that come up with the diamonds, or are sometimes even encased within them. Fibrous, dirty-looking diamond pieces containing solid or liquid impurities would disqualify them as jewelry, but carry potentially valuable chemical information.
Up to now, most researchers have concentrated on solid inclusions, such as tiny bits of garnet, to determine the ages of diamonds. But the ages that solid inclusions indicate can be debatable, because the inclusions may or may not have formed at the same time as the diamond itself. Encapsulated fluids, on the other hand, are the real thing, the stuff from which the diamond itself formed.
Method Of Diamond Fluid research
What the scientist did different this time was find a way to date the fluids. They did this by measuring traces of radioactive thorium and uranium, and their ratios to helium-4, a rare isotope that results from their decay.
The scientists also figured out the maximum rate at which the nimble little helium molecules can leak out of the diamond – without which data, conclusions about ages based on the abundance of the isotope could be thrown far off. (As it turns out, diamonds are very good at containing helium.)
The team identified three distinct periods of diamond formation. These all took place within separate rock masses that eventually combined into present-day Africa.
- The oldest took place between 2.6 billion and 700 million years ago. Fluid inclusions from that time show a distinct composition, extremely rich in carbonate minerals. The period also coincided with the buildup of great mountain ranges on the surface, apparently from the collisions and squishing together of the rocks. These collisions may have had something to do with production of the carbonate-rich fluids below, although exactly how is vague, the researchers say.
- The next diamond-formation phase spanned a possible time frame of 550 million to 300 million years ago, as the proto-African continent continued to rearrange itself. At this time, the liquid inclusions show, the fluids were high in silica minerals, indicating a shift in subterranean conditions. The period also coincided with another major mountain-building episode.
- The most recent known phase took place between 130 million years and 85 million years ago. Again, the fluid composition switched: Now, it was high in saline compounds containing sodium and potassium. This suggests that the carbon from which these diamonds formed did not come directly from the deep earth, but rather from an ocean floor that was dragged under a continental mass by subduction. This idea, that some diamonds’ carbon may be recycled from the surface, was once considered improbable, but recent research b has increased its likelihood.
- One interesting find: At least one diamond encapsulated fluid from both the oldest and youngest eras. The shows that new layers can be added to old crystals, allowing individual diamonds to evolve over vast periods of time.
It was at the end of this most recent period, when Africa had largely assumed its current shape, that a great bloom of kimberlite eruptions carried all the diamonds the scientists studied to the surface. The solidified remains of these eruptions were discovered in the 1870s, and became the famous De Beers mines. Exactly what caused them to erupt is still part of the puzzle.
The tiny diamond-encased droplets provide a rare way to link events that took place long ago on the surface with what was going on at the same time far below.
When quizzed whether the findings could help geologists find new diamond deposits, the research team relied “Probably not,” . But, added, the method could be applied to other diamond-producing areas of the world, including Australia, Brazil, and northern Canada and Russia, to disentangle the deep histories of those regions, and develop new insights into how continents evolve.


Cancer survival rates increasing in Northern Ireland Despite the rising incidence of cancer in Northern Ireland, the amount of people surviving the disease in the united states is increasing significantly year on year. Every year there are between 50-60 women and men who survive the deadly effects of cancers who previously would have died ed treatment review . The survival prices in Northern Ireland for cancers including colorectal and breasts are among the best in the UK, and its own patients are profiting from improved treatment outcomes by up to four percent better than those for England and Wales.
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Cancer-causing chemicals found in e-cigarette vapor E-cigarette vapor can contain cancer-causing formaldehyde at levels to 15 occasions higher than regular smoking cigarettes up, a fresh study finds. Researchers discovered that e-cigarettes operated at high voltages produce vapor with huge amounts of formaldehyde-containing chemical substances. This may pose a risk to users who raise the voltage on the e-cigarette to improve the delivery of vaporized nicotine, said research co-author James Pankow, a professor of chemistry and civil and environmental engineering at Portland Condition University in Oregon. We’ve found there is a hidden form of formaldehyde in e-cigarette vapor which has not really typically been measured. It’s a chemical which has formaldehyde in it, and that formaldehyde can be released after inhalation, Pankow said.