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Sunday 31 July 2016

Liocourt’s law for tree diameter distribution in forest stands

Published Date
Volume 73, Issue 3, pp 751–755

Title

Liocourt’s law for tree diameter distribution in forest stands

  • David Gasparotto
  • Key message

    Liocourt’s legacy for the law on steady-state uneven-aged forests has been questioned. We propose a new interpretation of his results published in 1898 and refer to a manuscript dated 1900 to clarify that he established this law.

    Context

    Liocourt’s law states that in steady-state uneven-aged forests, the number of trees in successive diameter classes of equal width form a decreasing geometric series. When referring to this law, most authors cite a paper by Liocourt published in 1898. The 1898 paper does not contain any explicit mathematical expression, but its results can be interpreted as supporting a geometric series with ratio 2. 

    Aims

    We reviewed Liocourt’s paper of 1898 to provide a new mathematical interpretation of his results, and reviewed other texts by Liocourt to identify the origin of his law. 

    Results

    The paper of 1898 supports a polynomial expression of degree 4 rather than a geometric series. The geometric series was explicitly introduced by Liocourt in a handwritten text dated 1900 that remains little-known. 

    Conclusion

    The 1898 text by Liocourt was a preliminary work on his law that was expressed in its current form in the manuscript dated 1900.

    Keywords

    de Liocourt’s law de Liocourt q Diameter distribution Exponential distributionUneven-aged forest
References

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http://link.springer.com/article/10.1007/s13595-016-0563-4

Study of Mechanical and Physical Properties of Palm Fiber Reinforced Acrylonitrile Butadiene Styrene Composite

Published Date

DOI: 10.4236/msa.2014.51006
Author(s)     
Budrun Neher, Md. Mahbubur Rahman Bhuiyan, Humayun Kabir, Md. Rakibul Qadir, Md. Abdul Gafur, Farid Ahmed
Department of Physics, Jahangirnagar University, Dhaka, Bangladesh; Department of Physics, Comilla University, Comilla, Bangladesh.
Department of Physics, Comilla University, Comilla, Bangladesh.
Department of Physics, Jahangirnagar University, Dhaka, Bangladesh.
PP and PDC, Bangladesh Council of Scientific and Industrial Research, Dhaka, Bangladesh.
PP and PDC, Bangladesh Council of Scientific and Industrial Research, Dhaka, Bangladesh.
Palm fiber (PF) reinforced acrylonitrile butadiene styrene (ABS) composite matrix was prepared by employing Injection Moulding Machine (IMM). Palm fiber was collected from ten different trees of different age group from Comilla region in Bangladesh. Three sets of samples were prepared for three different wt% (5%, 10% and 20%) of fiber contents. The mechanical (tensile strength, flexural stress, micro hardness, Leeb’s rebound hardness) and physical (bulk density and water absorption) properties were measured. The observed result reveals that the tensile strength (TS) and flexural stress (FS) were decreased with increasing fiber contents in the PF-ABS composites except 10% fiber content.
Cite this paper
B. Neher, M. Bhuiyan, H. Kabir, M. Qadir, M. Gafur and F. Ahmed, "Study of Mechanical and Physical Properties of Palm Fiber Reinforced Acrylonitrile Butadiene Styrene Composite," Materials Sciences and Applications, Vol. 5 No. 1, 2014, pp. 39-45. doi: 10.4236/msa.2014.51006.
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[3]R. A. Khan, M. A. Khan, H. U. Zaman, N. Noor, T. Huq, A. Khan, K. Dey, B. Sarker, S. Saha, M. M. Rahman, M. Saha and M. A. Gafur, “Study on the Mechanical and Thermal Properties of Jute-Reinforced Methyl Acrylate Grafted PET Composites,” Polymer-Plastic Technology and Engineering, Vol. 49, 2010, pp. 373-380.
[4]R. Akter, R. Sultana, Md. Z. Alam, Md. R. Qadir, M. H. A. Begum and Md. A. Gafur, “Fabrication and Characterization of Woven Natural Fiber Reinforced Unsaturated Polyster Resin Composites,” International Journal of Engineering & Technology, Vol. 13 No. 2, 2013, pp. 122-128.
[5]S. Selke, “Biodegradation and Packageing,” Pira International Reviews: Surrey, UK, 1996.
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http://dx.doi.org/10.1016/S0142-9418(00)00068-4
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http://en.wikipedia.org/wiki/Acrylonitrile_butadiene_styrene
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[9]ASTM Designation: D 3039/D 3039M-00, “Standard Test Method for Tensile Properties of Polymer Matrix Composites Materials”.
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[15]S.-H. Lee and S. Q. Wang, “Biodegradable Polymers/ Bamboo Fiber Biocomposite with Bio-Based Coupling Agent,” Composites: Part A, Vol. 37, 2006, pp. 80-91.
[16]I. Ahmad, D. R. Abu Bakar and S. N. Mokhilas, “Recyled PET for Rice Husk/Polyester Composites,” AJSTD, Vol. 22, No. 4 pp. 345-353. http://eprints.utp.edu.my/3294/
[17]S. Taj, M. A. Murawar and S. Khan, “Natural Fiber-Reinforced Polymer Composites,” Proceedings of the Pakistan Academy of Sciences, Vol. 44, No. 25, 2007, pp. 129-144.
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[19]A. H. Bhuiyan, M. F. Mina, S. Seema, M. M. Khan, M. J. Rahman and M. A. Gafur, “Structural, Elastic and Thermal Properties of Titanium Dioxide Filled Isostatic Polypropylene,” Journal of Polymer Research, Vol. 18, No. 5, 2011, pp. 1073-1079.
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Bodybuilders Who Use Full-Body Workout Routines

Bodybuilders Who Use Full-Body Workout Routines
Full-body routines allow you to stimulate your muscles with greater frequency. Photo Credit Photodisc/Photodisc/Getty Images
Between 1940 and the early 1970's, bodybuilders such as Steve Reeves, Reg Park, Arnold Schwarzenegger, Dave Draper and Casey Viator built their muscular physiques with full-body workouts. Full-body routines became less popular from the late 1970's with bodybuilders switching to split routines that involve working specific muscle groups each workout. But in 2014, bodybuilders such as Dexter Jackson still include full-body workouts in their routines. Full-body and split routines have specific advantages and disadvantages. But whichever one you choose, don't overtrain by spending too long in the gym, and ensure you get enough rest between workouts to allow your muscles time to recover and grow.

Looking at Full-body Routines

Three-day-a-week full-body workouts stimulate your muscles more frequently; this induces more muscle-growth. Full-body workouts expend more energy because of the number of muscle groups you exercise each session. This helps you burn more fat. On the flip side, full-body workouts may mean spending too long in the gym and overtraining. You may also tire toward the end of your workout, and unable to hit latter muscle groups with the same intensity you did earlier muscle groups.

The 5x5 Full-body Routine

Englishman Reg Park used the 5x5 full-body workout system to win the Mr. Universe title in 1951,1958 and 1965. This is the basis for Mehdi Hadim's Stronglifts system. Park's routine evolves around using heavy weights for compound multi-joint exercises, doing five sets of five reps. Do two warm-up sets and three heavy sets. Increase your weight once you can complete five reps for each heavy set. Rest two minutes between sets, and work out three times a week, ideally on Monday, Wednesday and Friday. Exercises include the bench press for your chest, barbell squats for legs, military presses for shoulders, bent-over rows for upper back, deadlifts for lower back and trapezius, barbell curls for biceps, lying triceps extension for triceps and standing calf raises for your calves. Park's workouts lasted two to three hours. Modify the system to avoid overtraining and reduce fatigue. Hit your chest and shoulders on different days. Do squats and deadlifts on different days.

Selecting Your Split Routine

With the variety of split routines available, choose the one that fits your lifestyle, suits your capabilities, and helps you gain the most muscle. Examples include the three-day split workout, four-day split workout, and the push, pull and legs workout. For a three-day split, hit your chest and back on Monday, your legs on Tuesday and shoulders and arms on Wednesday. Rest for a day or two, and repeat the sequence over the next three days. For a four-day split, do your chest and triceps on Monday, back and biceps on Tuesday, quadriceps and hamstrings on Wednesday and your shoulders and calves on Thursday. Rest for a day or two and repeat the sequence over the next four days. For the push, pull and legs workout, do pushing exercises that hit your chest, shoulders and triceps on Monday, hit your legs on Tuesday, and do pulling exercises for your back and biceps on Wednesday. Rest for a day or two and repeat the sequence.

Specifics of A Split Routine

For your split routine, do two exercises per muscle group. For example, hit your chest with three to five sets of the barbell bench press and three sets of bench flys. Work your upper back with three to five sets of bent-over rows and three sets of lat pulldowns. Hit your shoulders with three to five sets of the military press, three sets of lateral raises, three sets of bent-over laterals, and three sets of dumbbell shrugs. Work your biceps with three sets of barbell curls, and three sets of alternate dumbbell curls. Target your triceps with three sets of triceps dips, and three sets of triceps pushdowns. For your legs, do three to five sets of barbell squats, three sets of leg curls, and three sets of calf raises.

Maintaining Intensity

As you are working fewer muscle groups each workout you are less likely to fatigue with a split routine. This enables you to use heavy weights for each exercise, maintain intensity, and fully tax each muscle. Provided you avoid doing too many exercises, or sets per exercise, you are less likely to overtrain by spending too long in the gym. On the negative side, split routines don't target your muscles with the same frequency as full-body workouts.
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Foot Exercises for Plantar Fasciitis

Foot Exercises for Plantar Fasciitis
A runner is pulling her heel back and stretching it. Photo Credit Jacob Ammentorp Lund/iStock/Getty Images
Plantar fasciitis involves pain and inflammation of a thick band of tissue in your foot known as the plantar fascia. The plantar fascia runs across the bottom of your foot and connects your heel bone to your toes. Plantar fasciitis is a frequent cause of heel pain. This condition is common in runners pregnant women, obese individuals and those who wear shoes with inadequate support. Stretching exercises for the plantar fascia can help relieve the pain of plantar fasciitis, but consult your doctor before beginning an exercise program.

Wall Stretch

A wall stretch can help to strengthen and stretch the calf, as well as the soleus and gastronemius, both muscles in the foot. Firmly plant your hands on a wall in front of you with your arms fully extended. Move one foot in front of the other. The foot with plantar fasciitis should remain in back. Slightly bend your knee on the leg in back. Hold this position until you feel your calf muscles stretching. Hold this position for 30 seconds. Repeat for three sets of 10 repetitions each day. Hold each repetition for 30 seconds.

Rolling Stretch

A rolling stretch can help prevent recurrences of plantar fasciitis, as well as the development of bone spurs. Complete this exercise in a seated position, with your back against the back of the chair. A majority of your weight should remain on the chair while completing this exercise. Place a cylinder-like object -- such as a can or a bottle -- underneath the heel of your foot. Slowly roll the cylinder-like object to your toes and then slowly bring it back down to your heel again. Apply firm pressure to your foot as your complete this exercise. Repeat the rolling stretch 10 times on the affected foot. Try to complete this exercise three times each day.

Stair Stretch

A stair stretch can help alleviate the pain of plantar fasciitis. Stand on the edge of a step on the balls of your feet. For added support, hold onto a railing. Slowly transfer your weight onto the foot with the plantar fasciitis and lower the heel of that foot to stretch your arch and your calf muscle. Once you feel a stretch, hold the position for 15 seconds. Slowly place yourself in the starting position and repeat this exercise 10 times.

Towel Stretch

A towel stretch can help with decreased flexibility and tightness in the Achilles tendon, the band of tissue that connects the calf muscles at the back of the lower leg to your heel bone. Sit on the floor with your legs extended in front of you. Loop a towel around the foot with plantar fasciitis. Slowly pull the towel toward your body, keeping your body straight. The only part of your body that will be moving is your foot. Your heel should raise slightly off of the floor. Hold this position for 15 seconds, relax for a few seconds, and repeat this exercise 10 times.
www.livestrong.com

Can I Exercise With Plantar Fasciitis?


Can I Exercise With Plantar Fasciitis?
Plantar fasciitis is a painful inflammation of the ligament in the bottom of your foot. Photo Credit Stockbyte/Stockbyte/Getty Images
Plantar fasciitis is a painful inflammation of the plantar fascia, a ligament on the bottom of your foot that connects the heel with the toes and supports the arch. Pain occurs in the arch of the foot and near the heel, and is worse in the morning until you have walked for a while.

Causes

Plantar fasciitis is caused by tight calf muscles that attach to the Achilles tendon, repetitive impact such as running, weight gain, poorly fitted shoes or a change in the intensity or frequency of your daily activities or your workout. The usual treatment includes rest and ice during the acute phase and then stretching exercises for the bottom of your foot and your calf. Avoid exercises that make your foot hurt or that involve impact like running or jumping until the condition improves.

Stretching the Bottom of Your Foot

While the pain is more acute, stretch your foot gently. Sitting with your painful foot stretched out in front of you, wrap a towel, scarf or exercise band around the ball of your foot. Pull on it gently to stretch the plantar fascia and hold the stretch for 30 seconds. Relax and then repeat the stretch three times. Stretch as far as you can without pain. Sitting in a chair, bring your injured foot as far as you can under the chair. Press the heel into the floor and hold the stretch for 30 seconds. Do this several times throughout the day.

Stretching Your Calf

Stand about an arm's length away from a counter or wall. Brace your hands against the counter or wall, with the unaffected leg closer to the wall and the affected leg back. Keep both heels on the floor and bend the front knee until you feel a stretch in the back of your calf on the affected leg. Hold for 30 seconds, relax and repeat three times.

Stretching the Calf and Foot Together

Stand with the balls of your feet on a stair, holding on to the stair railing with your hands. Drop your heels below the level of the stair until you feel a stretch in the bottom of your feet and back of your legs. Hold the stretch for 30 seconds, then relax and repeat three times. Avoid bouncing, as static stretching produces better results.

Pain Relief

Sitting in a chair, roll the arch of your foot back and forth over a tennis ball. If your foot is very sore, use a frozen can of juice -- in a plastic bag -- or a cold bottle of water. Fill a basin with marbles or small round stones to a depth of about an inch. Put in enough cold water to cover your feet. Sitting in a chair, put your sore foot into the cold water and roll your arch around over the marbles. Pick up marbles with your toes to exercise muscles on the bottom or your feet. Roll the edges of your feet around in the marbles.

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How to Use an Athletic Wrap for Foot Arches

How to Use an Athletic Wrap for Foot Arches
How to Use an Athletic Wrap for Foot Arches Photo Credit Dale Davidson/Demand Media
Pain the arch of your foot can have several causes, including plantar fasciitis, posterior tibial tendinitis and medial tibial stress syndrome, according to Podiatry Today. As the "British Journal of Sports Medicine" points out, arch pain is sometimes linked to injuries on the inside, or medial side, of the leg and at the knee. To relieve the pain associated with these conditions, as well as to prevent further injury, use athletic taping techniques to support and stabilize the arch. The low-dye taping technique is generally easier to master, but the X-crossing technique may offer slightly greater support for the plantar region of the foot.

Low-Dye Technique

Step 1

How to Use an Athletic Wrap for Foot Arches
Photo Credit Dale Davidson/Demand Media
Place your foot in a neutral position (not flexed or pointed) with the big toe bent downward slightly.

Step 2

How to Use an Athletic Wrap for Foot Arches
Photo Credit Dale Davidson/Demand Media
Wrap a 1-inch wide strip of tape around your heel, beginning at the bottom of your big toe and ending under the bottom of your pinkie toe. Keep the tape low on the ankle so you do not irritate the Achilles tendon, but not so low that it's under the heel.

Step 3

How to Use an Athletic Wrap for Foot Arches
Photo Credit Dale Davidson/Demand Media
Wrap the tape under your arch toward the inside of your foot. Begin on the outside of your foot, and use 2-inch strips. Continue to place strips across your arch, overlapping them by one half each, until you have strips from the bottom of the ball of your foot to the beginning of your heel.

Step 4

How to Use an Athletic Wrap for Foot Arches
Photo Credit Dale Davidson/Demand Media
Repeat Step 2, adding another anchor wrap around your heel to secure the arch strips.

X-Crossing Technique

Step 1

How to Use an Athletic Wrap for Foot Arches
Photo Credit Dale Davidson/Demand Media
Place the foot in a neutral position with the big toe bending downward slightly.

Step 2

How to Use an Athletic Wrap for Foot Arches
Photo Credit Dale Davidson/Demand Media
Wrap the tape from the bottom of your big toe around your heel and back across the bottom of your foot to the starting position. Use a 1-inch-wide strip. The tape should go from inside the foot to outside the foot.

Step 3

How to Use an Athletic Wrap for Foot Arches
Photo Credit Dale Davidson/Demand Media
Cut a long strip of tape to apply in an "X" across the arch of your foot. Apply one end of the tape at the bottom of your pinkie toe. Bring the tape across the arch and wind it around the back of the heel. Cross back over the tape at the arch and anchor the end under the big toe. The tape should form an “X” on the underside of your foot's arch.

Step 4

How to Use an Athletic Wrap for Foot Arches
Photo Credit Dale Davidson/Demand Media
Place several 2-inch strips from the outside of your foot toward the inside, going over the "X" that is formed by the tape under your foot at the arch.
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Unusually aggressive primary cloacogenic carcinoma of the vulva: A case report and literature review

 Published Date

DOI: 10.4236/crcm.2013.25081
Author(s)  
Rajni Chibbar, Kimberly A. Wood, Christopher K. Giede, Anita Agrawal
Department of Pathology, University of Saskatchewan, Saskatoon, Canada.
College of Medicine, University of Sasktchewan, Saskatoon, Canada.
Department of Obstetrics and Gynecology, Royal University Hospital, Saskatoon, Canada.
Department of Obstetrics and Gynecology, University of Saskatchewan, Saskatoon, Canada;.

Abstract

Vulvar cancer is an uncommon tumor and represents 3%-5% of all female genital tract malignancies. The overall incidence is 1.5/100,000 women. Histopathologically the vast majority (90%) are squamous cell carcinomas. Primary cloacogenic carcinoma of the vulva is extremely rare with less than 20 cases reported in English literature [1]. These tumors are thought to arise from embryonic or ectopic rests of cloacogenic tissue. The majority of these reported cases is relatively indolent cancer, only one case of cloacogenic carcinoma of the vulva reported metastatic spread to the inguinal lymph nodes and none that describe distant metastases. Here we present an aggressive and diagnostically challenging case of cloacogenic carcinoma of the vulva and a review of current literature to date. 
Cite this paper
Chibbar, R. , Wood, K. , Giede, C. and Agrawal, A. (2013) Unusually aggressive primary cloacogenic carcinoma of the vulva: A case report and literature review. Case Reports in Clinical Medicine2, 302-305. doi: 10.4236/crcm.2013.25081.



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http://www.scirp.org/journal/PaperInformation.aspx?PaperID=35609




Theoretical Considerations about the Steady State Combustion of Wood Char in a Bubbling Fluidized Bed Reactor

Published Date
DOI: 10.4236/epe.2013.53021
Author(s
Transport Phenomena Research Center, Department of Mechanical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal.
A theoretical study on the performance of steady state bubbling fluidized bed burners is presented using a simple mathematical model. The proposed model has pedagogical and practical advantages due to its simplicity. The calculations, whose results are plotted in several graphics, were based on data obtained in laboratory scale experiments. The experiments were carried out with wood chars and the model allows a proper evaluation of physical and chemical phenomena taking place inside the reactor, as well as a fast approach to the pre-design phase, before going towards more complex and time consuming numerical modeling. In the first part of the paper the steady state modeling is compared with the combustion of successive batches of char particles. Afterwards, the performance of a 1 m diameter bed operating from 700 to 800 is shown.
Cite this paper
C. Pinho, "Theoretical Considerations about the Steady State Combustion of Wood Char in a Bubbling Fluidized Bed Reactor," Energy and Power Engineering, Vol. 5 No. 3, 2013, pp. 212-224. doi: 10.4236/epe.2013.53021.
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