Experimental investigation of mechanical and microstructural properties of cemented paste backfill containing maple-wood filler

Published Date
15 September 2016, Vol.121:222–228, doi:10.1016/j.conbuildmat.2016.05.118

Title 
Experimental investigation of mechanical and microstructural properties of cemented paste backfill containing maple-wood filler

• Author 

• Babak Koohestani ^a,b
• Ahmed Koubaa ^b
• Tikou Belem ^a,,
• Bruno Bussière ^a
• Hassan Bouzahzah ^a

• aResearch Institute in Mining and Environment (RIME), Université du Québec en Abitibi-Témiscamingue (UQAT), 445 Boul. de l’Université, Rouyn-Noranda, Quebec J9X 5E4, Canada
• bInstitute of Forest Research (IFR), Université du Québec en Abitibi-Témiscamingue (UQAT), 445 Boul. de l’Université, Rouyn-Noranda, Quebec J9X 5E4, Canada

Received 6 October 2015. Revis

Abstract

This experimental study investigates the influence of maple-wood sawdust addition on the mechanical and microstructural properties of cemented paste backfill (CPB). Mechanical properties of CPB were determined by uniaxial compressive strength (UCS) tests and microstructural changes were evaluated by mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM) analysis. Results indicate that the addition of 12.5% maple-wood sawdust (by dry mass of binder) improves the strength development of CPB specimens at later hydration age (91 curing days). However, at a higher maple-wood sawdust content of 14.5%, the UCS showed lower improvement. Moreover, MIP and SEM analysis results revealed that the 12.5% wood filler addition made the CPB material less porous and more compact by increasing the mineral content formed by cement hydration. The positive influence of maple-wood sawdust on CPB was associated with higher binder content (⩾5%) and mid- to long-term curing times (⩾56 days).

Keywords

Mine tailings

Maple-wood sawdust

Binder

Cemented paste backfill

Compressive strength

MIP

Porosity

SEM

---

Fig. 1.

 Table 1

Table 1.

 Table 2

Table 2.

 Table 3

Table 3.

 Table 4

Table 4.

 Table 5

Table 5.

 Table 6

Table 6.

Fig. 2.

 Table 7

Table 7.

 Table 8

Table 8.

Fig. 3.

Fig. 4.

Fig. 5.

• ⁎ 
  Corresponding author.

For further details log on website :

http://www.sciencedirect.com/science/article/pii/S0950061816308546

Preparation of biomorphic porous zinc oxide by wood template method

Published Date
July 2016, Vol.42(9):10704–10710, doi:10.1016/j.ceramint.2016.03.188

Title 
Preparation of biomorphic porous zinc oxide by wood template method

• Author 

• Ming Zhou
• Deli Zang
• Xianglin Zhai
• Zhengxin Gao
• Wenbo Zhang
• Chengyu Wang ^,

• Key Laboratory of Bio-Based Material Science and Technology, Ministry of Education, Northeast Forestry University, Harbin 150040, China

Received 30 November 2015. Revised 24 February 2016. Accepted 24 March 2016. Available online 25 March 2016.

Abstract

This paper presents an effective method to fabricate highly porous zinc oxide (ZnO) derived from different wood templates, where the microstructure features of wood template were well reproduced in the final product. Biomorphic ZnO was fabricated via the sol–gel method by the infiltration of the precursor sol into the wood template and the sintering of wood template at high temperature under air atmosphere. Many characterization methods such as x-ray diffraction (XRD), scanning electron microscopy (SEM) and pore size analyzer detection were used to investigate the crystalline phase and microstructure of the product as well as the pore size of biomorphic ZnO. In our work, highly porous ZnO derived from different wood templates had been prepared. The relevant results revealed that the specie of wood template and sintering temperature played vital roles in the pore size, specific surface area and pore volume of the product.

Keywords

• Zinc oxide
• Wood template
• Porous structure
• Sol–gel method

---

 Table 1

Table 1.

Fig. 1.

Fig. 2.

Fig. 3.

Fig. 4.

Fig. 5.

Fig. 6.

Fig. 7.

Fig. 8.

 Table 2

Table 2.

 Table 3

Table 3.

Fig. 9.

• ⁎ 
  Corresponding author.

For further details log on website :

http://www.sciencedirect.com/science/article/pii/S0272884216303364

Effects of Alcohol on Sports Performance

Alcohol increases your chances of becoming dehydrated. Photo Credit Stockbyte/Stockbyte/Getty Images

Alcohol consumption is a major concern in the sports world. It remains one of the most abused drugs among athletes despite the well-known negative effects it can have on the mind and body. Drinking often begins among athletes during the high school years. If you play sports, it's essential that you understand how alcohol can damage -- even destroy -- your athletic ambitions.

Muscle Development

Strength training is an important part of getting your body fit for athletic activity, but drinking alcohol can negate the results of your workouts. Its toxic effects also impair your body's ability to produce ATP, which is the primary energy source for your muscles. Alcohol affects your ability to get adequate sleep, resulting in a lack the human growth hormone that helps build strong, larger muscles. It also causes the liver to release a chemical that impairs testosterone, which is a key hormone in muscle development

Aerobic Performance

Aerobic activity involves the use of oxygen to energize the large muscle groups needed to physically perform. It increases blood circulation and your heart rate. Your body's ability to respond aerobically is vital to play many sports, but alcohol can interfere with these physical reactions. It slows respiratory function, affects body temperature regulation and increases your risk for dehydration -- all of which affect your aerobic performance. Dehydration is particularly dangerous, as it can lead to heatstroke, seizures and shock.

Cognitive & Motor Function

Being able to learn strategies and respond quickly -- both physically and mentally -- are vital when you're playing sports. Alcohol can affect how your brain is able to form memories, resulting in your inability to learn and recall new information. Drinking five alcoholic beverages in one night can affect your cognitive function for up to three days. While low alcohol amounts can improve some motor skills, moderate amounts cause slow reaction time, decreased balance and poor hand-eye coordination.

Long-term Effects

Many of alcohol's effects on sports performance occur quickly, but long-term use can lead to serious repercussions as well. It affects your cardiovascular function in response to physical activity in addition to causing muscle weakness. Chronic drinking also affects your body's ability to absorb essential nutrients including zinc, folic acid and vitamin B12. It can alter your hormonal balance as well as cause heart damage.

www.livestrong.com

Benefits of Fresh Lemon Juice With Rind

Bowl of lemons Photo Credit LuminaStock/iStock/Getty Images

Overview

Lemons are a citrus fruit characterized by a bright yellow color and sour taste. A lemon is full of nutrients, including vitamin C, beta carotene, vitamin A, folate, calcium, magnesium, phosphorus and potassium. The peel or rind of a lemon contains essential oils and many of the nutrients present in the flesh. Lemon rind also has higher oxalate levels, which is a compound that can crystallize and create problems in concentrated doses. Remove the rind when making fresh juice if you have kidney or gall bladder problems. Lemonade is a popular summer drink, but is usually loaded with refined sugar. Juicing fresh lemons gives all the benefits without the blood sugar dangers. Lemon juice is quite tart and strong and is best combined with other juices such as apple, pear or carrot.

Free Radical Protection

Free radicals are compounds in your body that move around and interact with healthy cells, causing damage. Free radical damage has been associated with cancer and inflammation in the body. Vitamin C will work to neutralize free radicals it comes into contact with, according to a report from Rice University.

Ease Urinary Tract Infection

Lemons have a diuretic action on the body, and can help ease a urinary tract infection, says A 2 Z of Health, Beauty and Fitness. Urinary tract infections are characterized by a burning sensation when you urinate and pressure in the lower abdomen.

Relieves Skin Problems

Lemon juice is acidic in nature, and as such a good choice to use as an astringent on your skin. The juice has the added benefit of containing many nutrients that a store bought astringent wouldn’t have. Dip a cotton ball into fresh lemon juice and apply it to your skin like any other astringent.

Concentrated Nutrition

When you juice a lemon along with the rind in a juice extractor, the result is pure pulp-free juice. Your body does not have to process the fiber by way of digestion, and all of the nutrients are concentrated in the juice. Juicing also gives you more control over what exactly is in the juice, says the Raw Food Diet Solution website.

Blood Pressure Control

The high content of vitamin C and other antioxidants in lemon juice could help lower blood pressure, says the University of Maryland Medical Center. High blood pressure can result in heart attack and stroke and is best to have at manageable levels. According to a 2012 report from Johns Hopkins Medical Center, 30 percent of adults in the United States have high blood pressure.

Arthritis Relief

The vitamin C in lemon juice plays a role in making collagen, which is part of the cartilage between your bones. It is the cartilage that is worn down and damaged in cases of osteoarthritis, says the University of Maryland Medical Center.

www.livestrong.com

How to Reduce Sleepiness Naturally

Eat better to avoid crashing at your desk. Photo Credit Photos.com/PhotoObjects.net/Getty Images

If you find it difficult to get through your day without taking a nap, you may need to make some changes to your lifestyle. Different from fatigue, sleepiness or drowsiness involves restless sleep patterns at night, which result in being tired during the day. If your doctor has ruled out sleep disorders, then altering your daytime behaviors and patterns may help you to sleep more soundly and have more energy during the day.

Step 1

Create a comfortable sleeping space. Trying to sleep in a room that is too hot or too cold, has a hectic feel to it or is noisy can greatly interfere with obtaining quality sleep at night, leaving you feeling sleepy during the day. Paint your bedroom in soothing colors, such as a soft blue, adjust the temperature and drown out any excess noise with a fan.

Step 2

Buy a comfortable mattress and pillows. The correct level of firmness is subjective to each person, but purchase bedding that is inviting and allows you to relax.

Step 3

Stick to a sleep schedule seven nights a week. Training your body to go to bed and wake up at the same time every day can help to set your body’s sleep-wake cycle.

Step 4

Limit the amount of caffeine that you consume during the day. Caffeine can backfire on you by staying in your system too long and affecting your ability to fall asleep or stay asleep through the night. Caffeine in the morning is usually acceptable but be aware of how drinking coffee, tea or soda in the afternoon affects your sleep patterns.

Step 5

Avoid nicotine and alcohol, both of which are stimulants and can affect your quality of sleep, leaving you to feel drowsy during the day.

Step 6

Eat a healthy diet that consists of fresh fruit and vegetables, whole grain carbohydrates, lean proteins and unsaturated fats. Sugar, white flour and saturated fats can place stress on your body, which can lead to a feeling of sleepiness.

Step 7

Exercise regularly during the day. Working out can relieve stress and help you to sleep more soundly at night. Avoid exercising close to bedtime since exercise can also give you a boost of energy.

Things You'll Need

• Paint
• Fan
• Mattress
• Pillows
• Fruit
• Vegetables
• Whole-grain carbohydrates
• Protein
• Unsaturated fats
• Gym

www.livestrong.com

Pretreatment studies on wheat straw and rice straw

Author Information

Seema J. Patel
Department of Biotechnology, GM Institute of Technology, Davanagere- 577006, Karnataka, India

R. Onkarappa
Department of Microbiology, Sahyadri Science College,Kuvempu University, Shimoga- 577201,Karnataka, India

SB Gurumurthy
Dept. of Microbiology, College of Agriculture, Bheemarayanagudi – 585287, Tq: Shahapur, Dist: Gulbarga

Abstract

Pretreatment is a necessary process for utilization of lignocellulosic materials to obtain ultimately high degree of fermentable sugars. In this work comparative study of chemical and microbiological treatments on the wheat and rice straw is carried out. Alkaline and acid treatments were selected as chemical treatments. Six fungi viz, Aspergillus niger A. awamori, Trichoderma reesei, T. viride, Phanerochaete chrysosporium, Pleurotus sajor-caju were used for microbial treatments. Microbial treatment resulted in release of more amount of reducing sugars (A. awamori treated wheat straw 18mg/g, rice straw 16mg/g) compared to chemical treatments (acid treated wheat straw 8mg/g, rice straw 10mg/g). Among the chemical treatments, alkali treatment gave good results (wheat straw 10mg/g, rice straw 11mg/g).  

Introduction

Cellulose is the most abundant carbohydrate polymer in wastes from forest products agriculture, fruits, and vegetables. Agricultural wastes and in fact all lignocellulosics can be converted into products that are of commercial interest such as ethanol, glucose, single cell protein (Solomon et al., 1999). In these waste products, the polysaccharides, cellulose and hemicellulose are intimately associated with lignin in the plant cell wall. The lignin component acts as a physical barrier and must be removed to make the carbohydrates available for further transformation processes (Kadam, 2000). Therefore, the pretreatment is a necessary process for utilization of lignocellulosic materials to obtain ultimately high degree of fermentable sugars. Pretreatment affects the structure of biomass by solubilizing hemicellulose, reducing crystallinity and increase the available surface area and pore volume of the substrate. There are numerous pretreatment methods or combinations of pretreatment methods available. In general, pretreatment techniques can be grouped into three categories: physical, chemical, and biological. Physical pretreatment methods include comminution, steam explosion etc. The most common chemical pretreatment methods used for cellulosic feedstocks are dilute acid, alkaline, organic solvent, ammonia, sulfur dioxide, carbon dioxide or other chemicals to make the biomass more digestible by the enzymes. Biological pretreatments are sometimes used in combination with chemical treatments to solubilize the lignin in order to make cellulose more accessible to hydrolysis and fermentation (Ayhan Demirbas, 2005). Pretreatment of cellulosic biomass in a cost-effective manner is a major challenge of cellulose-ethanol technology research and development. In the present work comparative study of chemical and biological treatments on wheat straw and rice straw are conducted.

Materials and Methods

Substrates: Wheat straw and rice straw were obtained from local fields of Davanagere district. Each raw material was powdered and sieved into a 1mm sieve and this was used as carbon source.

Isolation of fungi: Screening of fungi capable of degrading cellulose was done (Abdul et al1999) from the soil of local paddy and wheat fields and fungi of interest were selected after proper identification through manuals and confirmation by MTTCC, Chandigarh.

Acid hydrolysis and saccharification 

One hundred gram of dried sample was weighed into 2000 ml conical flasks and 1000 ml of sulphuric acid were added to the conical flask. The flasks were covered with aluminium foil and heated for two hours on flame. The flask was allowed to cool and filtered through Whatman No.1 filter paper. The pH was adjusted to 4.5 with 0.4 M sodium hydroxide (Humphrey and Caritas 2007). 

Alkaline hydrolysis

One hundred gram of dried sample was weighed into 2000 ml conical flask and 1000 ml of 0.25 M sodium hydroxide solution was added to the conical flask .The flask was left for one hour, after which the mixture was neutralized with 0.1 M hydrochloric acid (HCL) to a pH of 4.5. The flask was allowed to cool at room temperature and filtered through Whatman No.1 filter paper. 

Culture medium

Mandles medium was prepared by adding (gl-1): urea 0.3, (NH4)2SO4 1.4, KH2PO4 2, CaCl2 0.3, MgSO47H2O 0.3, bacto peptone 0.75, and yeast extract 0.25. Trace elements were also added, using a 1% (v/v) solution of salts(mll-1):FeSO47H2O 0.5, MnSO4 0.16, ZnSO4 0.14, CoCl2 2. pH was adjusted to 5.5-6.0 before sterilization (Bollok and Reczey 2000).

Culture conditions

10g /l of each residue was taken in conical flask containing 200ml of Mandle’s medium. The conical flasks were plugged with cotton and sterilized at 15lbs per sq.inch for 20 minutes. Each flask was inoculated with 4-5 discs of different fungi. These flasks were incubated at room temperature for 5days on an orbital shaker. After five days mycelium was separated by filtration through Whatman filter paper No.1. The filtrate was used for further studies (Harpreet et al., 1998).

Determination of total carbohydrate: The carbohydrate content of untreated and pretreated raw materials in the culture broth was measured by phenol sulphuric acid method (Thimmaiah, 1999) with glucose as standard.

Determination of reducing sugars: Reducing sugars in untreated and pretreated raw materials in the culture broth were determined by dinitrosalicylic acid (DNS) method (Miller, 1959) with glucose as standard.

Results and discussion

Initial composition of the raw materials was determined (Table 1). Pretreatment of raw materials makes it accessible for microbial treatment. So chemical treatments were conducted (table 2). Results of fungal treatments are shown in table 3. 

Figure 1

Table 1 Initial composition of raw materials

Figure 2

Table 2 Results of chemical treatment

Figure 3

Table 3 Results of fungal treatment

Autoclaving for sterilization has affected and resulted in increase in sugar release. With fungal treatment still increase in the yield of sugars was observed. Treatments with A. awamori and A. niger has shown better yield of reducing sugar compared to any of the two chemical treatments. Because pretreatment of cellulosic biomass in a cost-effective manner is a major challenge of cellulose-ethanol technology research and development, with the results of present work we have shown that microbial treatment, which is less costly and with less severe physical conditions, gives better yield of sugars from cellulosic residues like wheat straw and rice straw.

References

1. Abdul Jalil Kader, Othman Omar and Loo Shu Feng, 1999 Isolation of cellulolytic fungi from the Bario Highlands, Sarawak. ASEAN Review of biodiversity and environmental conservation (ARBEC).,Article XX: 1-3.
2. Ayhan Demirbas, 2005. Bioethanol from celulosic materials: A renewable motor fuel from biomass. Energy Sources, 27: 327-337.
3. Bollok, M. and Reczey, K, 2000 Cellulase enzyme production by various fungal strains on different carbon sources. Acta Alimentaria, 29(2): 155-168.
4. Harpreet, S., Bajaj, K.L., and Arneja, J.S, 1998. Biochemical studies on bioconversion of rice straw to ethanol. Ind. J. Ecol., 25(1): 62-65.
5. Humphrey, C. Nzelibe and Caritas, U. Okafoagu, 2007. Optimization of ethanol production from Garcinia kola(bitter kola) pulp agrowaste. African Journal of Biotechnology, 6 (17):2033-2037.
6. Kadam, K.L., Forrest, L.H., and Jacobson, W.A, 2000 Rice straw as a lignocellulosic resource collection, processing, transportation and environmental aspects. Biomass Bioenergy, 8: 369-389.
7. Miller, G.L, 1959. Use of DNS reagent for the measurement of reducing sugar. Anal.Chem., 31: 426-428.
8. Solomon, B.O., Amigun, B., Betiku, E., Ojumu, T.V., Layokun, S.K, 1999. Optimization of Cellulase Production by Aspergillus flavus Linn Isolate NSPR 101 Grown on Bagasse. JNSChE ,16: 61-68
9. Thimmaiah, S. K, 1999 Standard methods of biochemical analysis. Kalyani Publishers, New Delhi.

• {full_citation}

For further details log on website :
http://ispub.com/IJMB/7/1/6373