Materials Lateral Research

Tim Hawkinson has used materials of all kinds. This lateral research will delve into the history, usage, making of, and basic information about the materials used by the artist. Tim Hawkinson uses many types of materials including, cardboard, feathers, fingernails, eggshells, plastic, and even sound. Yes sound as a material.

CARDBOARD:

a material made from cellulose fiber (as wood pulp) like paper but usually thicker

http://www.merriam-webster.com/dictionary/cardboard

“Corrugated fiberboard or “combined board” has two main components: the liner and the medium. Both are made of a special kind of heavy paper called containerboard. Linerboard is the flat facing that adheres to the medium. The medium is the wavy, fluted paper in between the liners.

The term has been used since at least as early as 1683 when, with a publication of that year stating that “The scabbards mentioned in printers’ grammars of the last century were of cardboard or millboard” The Kellogg brothers first used paperboard cartons to hold their flaked corn cereal, and later, when they began marketing it to the general public, a heat-sealed bag of Wax paper was wrapped around the outside of the box and printed with their brand name. This marked the origin of the cereal box, though in modern times, the sealed bag is plastic and is kept inside the box rather than outside. Another early American packaging industry pioneer was the Kieckhefer Container Company, run by John W. Kieckhefer, which excelled in the use of fibre shipping containers, which especially included the paper milk carton.”

http://www.fibrebox.org/Info/WhatIsCorrugated.aspx

http://books.google.com/books?id=jkRFAAAAYAAJ&pg=PA407&dq=cardboard+OR+card-board&hl=en&ei=3clATcXTFYGClAfF8PH9Ag&sa=X&oi=book_result&ct=result&resnum=2&ved=0CEYQ6AEwAQ#v=onepage&q=cardboard%20OR%20card-board&f=falsev

FEATHERS:

Regarding Hawkinson’s Sherpa, 2008

“One of the epidermal growths that form the distinctive outer covering, or plumage, on birds and some non-avian theropod dinosaurs. They are considered the most complex integumentary structures found in vertebrates, and indeed a premier example of a complex evolutionary novelty.  They are among the characteristics that distinguish the extant Aves from other living groups. Feathers have also been noticed in those Theropoda which have been termed feathered dinosaurs. Although feathers cover most parts of the body of birds, they arise only from certain well-defined tracts on the skin. They aid in flight, thermal insulation, waterproofing and coloration that helps in communication and protection.

Feathers are among the most complex integumentary appendages found in vertebrates and are formed in tiny follicles in the epidermis, or outer skin layer, that produce keratin proteins. The β-keratins in feathers, beaks and claws — and the claws,scales and shells of reptiles — are composed of protein strands hydrogen-bonded into β-pleated sheets, which are then further twisted and crosslinked by disulfide bridges into structures even tougher than the α-keratins of mammalian hair, horns and hoof. The exact signals that induce the growth of feathers on the skin are not known but it has been found that the transcription factor cDermo-1 induces the growth of feathers on skin and scales on the leg.

Feathers insulate birds from water and cold temperatures. They may also be plucked to line the nest and provide insulation to the eggs and young. The individual feathers in the wings and tail play important roles in controlling flight. Some species have a crest of feathers on their heads. Although feathers are light, a bird’s plumage weighs two or three times more than its skeleton, since many bones are hollow and contain air sacs. Color patterns serve as camouflage against predators for birds in their habitats, and by predators looking for a meal. As with fish, the top and bottom colors may be different to provide camouflage during flight. Striking differences in feather patterns and colors are part of the sexual dimorphism of many bird species and are particularly important in selection of mating pairs. In some cases there are differences in the UV reflectivity of feathers across sexes even though no differences in color are noted in the visible range. The wing feathers of male Club-winged Manakins Machaeropterus deliciosus have special structures that are used to produce sounds by stridulation.

Some birds have a supply of powder down feathers which grow continuously, with small particles regularly breaking off from the ends of the barbules. These particles produce a powder that sifts through the feathers on the bird’s body and acts as a waterproofing agent and a feather conditioner. Powder down has evolved independently in several taxa and can be found in down as well as pennaceous feathers. They may be scattered in plumage in the pigeons and parrots or in localized patches on the breast, belly or flanks as in herons and frogmouths. Herons use their bill to break the feathers and to spread them while cockatoos may use their head as a powder puff to apply the powder. Waterproofing can be lost by exposure to emulsifying agents due to human pollution. Feathers can become waterlogged and birds may sink. It is also very difficult to clean and rescue birds whose feathers have been fouled by oil spills. The feathers of cormorants soak up water and help in reducing buoyancy and thereby allowing the birds to swim submerged.

Bristles are stiff, tapering feathers with a large rachis but few barbs. Rictal bristles are bristles found around the eyes and bill. They may serve a similar purpose to eyelashes and vibrissae in mammals. It has been suggested that they may aid insectivorous birds in prey capture or that it may have sensory functions, however there is no clear evidence. In one study, Willow Flycatchers (Empidonax traillii) were found to catch insects equally well before and after removal of the rictal bristles.

Grebes are peculiar in their habit of ingesting their own feathers and also feeding them to their young. Observations on the diet and feather eating frequency suggest that ingesting feathers particularly down from their flanks aids in forming easily ejectable pellets along with their diet of fish.

ontour feathers are not uniformly distributed on the skin of the bird except in some groups such as the Penguins, ratites and screamers. In most birds the feathers grow from specific tracts of skin called pterylae while there are regions which are free of feathers called apterylae. Filoplumes and down may arise from the apteriae, regions between the pterylae. The arrangement of these feather tracts, pterylosis or pterylography, varies across bird families and has been used in the past as a means for determining the evolutionary relationships of bird families.”

 http://www.yale.edu/eeb/prum/pdf/Prum_n_Brush_2002.pdf

http://www.yale.edu/eeb/prum/pdf/Prum_n_Brush_2003.pdf

http://www.orn.mpg.de/documents/peters/Delhey_AmNat2007_copy.pdf

FINGERNAILS:

TH-BirdTim Hawkinson: Bird, 1997

“A nail is a horn-like envelope covering the dorsal aspect of the terminal phalanges of fingers and toes in humans, most non-human primates, and a few other mammals. Nails are similar to claws in other animals. Fingernails and toenails are made of a tough protein called keratin, as are animals’ hooves and horns. The mammalian nail, claw, and hoof are all examples of unguis [plural ungues]. The nail consists of the nail plate, the nail matrix and the nail bed below it, and the grooves surrounding it.

The matrix is sometimes called [2] the matrix unguis, keratogenous membrane, nail matrix, or onychostroma. It is the tissue (or germinal matrix) which the nail protects.[3] It is the part of the nail bed that is beneath the nail and contains nerves,lymph and blood vessels.[4] The matrix is responsible for producing cells that become the nail plate. The width and thickness of the nail plate is determined by the size, length, and thickness of the matrix, while the shape of the fingertip itself shows if the nail plate is flat, arched or hooked.[5] The matrix will continue to grow as long as it receives nutrition and remains in a healthy condition.[4] As new nail plate cells are made, they push older nail plate cells forward; and in this way older cells become compressed, flat, and translucent. This makes the capillaries in the nail bed below visible, resulting in a pink color.[6]

The lunula (“small moon”) is the visible part of the matrix, the whitish crescent-shaped base of the visible nail.[7] The lunula can best be seen in the thumb and may not be visible in the little finger.

The nail bed is the skin beneath the nail plate.[7] Like all skin, it is made of two types of tissues: the deeper dermis, the living tissue which includes capillaries and glands,[8] The epidermis, the layer just beneath the nail plate, moves toward the finger tip with the plate. The epidermis is attached to the dermis by tiny longitudinal “grooves”[5] called matrix crests (cristae matricis unguis).[3][8] In old age, the nail plate becomes thinner so that these grooves become more visible.[5]

The nail sinus (sinus unguis) is where the nail root is;[3] i.e. the base of the nail underneath the skin. It originates from the actively growing tissue below, the matrix.[4]

The nail plate (corpus unguis)[3] is the hard part of the nail, made of translucent keratin protein. Several layers of dead, compacted cells cause the nail to be strong but flexible.[5] Its (transversal) shape is determined by the form of the underlying bone.[5] In common usage, the word nail often refers to this part only.

The free margin (margo liber) or distal edge is the anterior margin of the nail plate corresponding to the abrasive or cutting edge of the nail.[3] The hyponychium (informally known as the “quick”)[9] is the epithelium located beneath the nail plate at the junction between the free edge and the skin of the fingertip. It forms a seal that protects the nail bed.[4] The onychodermal band is the seal between the nail plate and the hyponychium. It is just under the free edge, in that portion of the nail where the nail bed ends and can be recognized by its glassy, greyish colour (in fair-skinned people). It is not visible in some individuals while it is highly prominent on others.[5]

The eponychium is the small band of epithelium that extends from the posterior nail wall onto the base of the nail.[3] Often and erroneously[contradictory] called the “proximal fold” or “cuticle”, the eponychium is the end of the proximal fold that folds back upon itself to shed an epidermal layer of skin onto the newly formed nail plate. This layer of non-living, almost invisible skin is the cuticle that “rides out” on the surface of the nail plate. Together, the eponychium and the cuticle form a protective seal. The cuticle on the nail plate is dead cells and is often removed during manicure, but the eponychium is living cells and should not be touched.[6] The perionyx is the projecting edge of the eponychium covering the proximal strip of the lunula.[3]

The nail wall (vallum unguis) is the cutaneous fold overlapping the sides and proximal end of the nail. The lateral margin (margo lateralis) lies beneath the nail wall on the sides of the nail and the nail groove or fold (sulcus matricis unguis) are the cutaneous slits into which the lateral margins are embedded.[3]

The paronychium is the border tissue around the nail[10] and paronychia is an infection in this area.Vitamin A is an essential micronutrient for vision, reproduction, cell and tissue differentiation, and immune function. Vitamin D and calcium work together in cases of maintaining homeostasis, creating muscle contraction, transmission of nerve pulses, blood clotting, and membrane structure. A lack of vitamin A, vitamin D, and calcium can cause dryness and brittleness. Sources of these micronutrients include fortified milk, cereal, and juices, salt-water fish, fish-liver oils, and some vegetables. Vitamin B12 is mainly found in animal sources such as liver and kidney, fish, chicken, and dairy products and therefore can cause intake issues in vegan populations. Not enough B12 vitamin can lead to excessive dryness, darkened nails, and rounded or curved nail ends. Insufficient intake of both vitamin A and B, as previously described, results in fragile nails with horizontal and vertical ridges.[23] Protein is a building material for new nails; therefore, low dietary protein intake may cause white nail beds. Dietary sources of this macronutrient include eggs, milk, cheese, meat, beans and legumes. A lack of protein combined with deficiencies in folic acid and vitamin C produce hangnails. Essential fatty acids play a large role in healthy skin as well as nails. As touched upon previously, essential fatty acids can be obtained through consumption of fish, flaxseed, canola oil, seeds, leafy vegetables, and nuts. Splitting and flaking of nails may be due to a lack of linoleic acid. Iron-deficiency anemia can lead to a pale color along with a thin, brittle, ridged texture. Iron deficiency in general may cause the nails to become flat or concave, rather than convex. Iron can be found in animal sources, called heme iron, such as meat, fish, and poultry, and can also be found in fruits, vegetables, dried beans, nuts, and grain products, also known as non-heme iron. Heme iron is absorbed fairly easily in comparison to non-heme iron; however, both types provide the necessary bodily functions.[24]”

http://emedicine.medscape.com/article/1126725-overview

http://www.biology-online.org/dictionary/Nail

https://www.nailsuperstore.com/tips/view.aspx?TipId=81

http://www.footdoc.ca/Website%20Nail%20Conditions%20(A%20Glossary).htm

http://books.google.com/books?id=gMSW59keA4UC&pg=PA101&hl=en#v=onepage&q&f=false

http://books.google.com/books?id=C8RAGvdzedoC&pg=PA416&hl=en#v=onepage&q&f=false

http://www.merriam-webster.com/dictionary/fingernail

http://books.google.com/books?id=gMSW59keA4UC&pg=PA101&hl=en#v=onepage&q&f=false

http://www.sciencedirect.com/science/article/pii/S0738081X10000611

Feneis, Heinz (2000). Pocket Atlas of Human Anatomy (4th ed.). Thieme. pp. 392–95. ISBN 3-13-511204-7.

Zempleni, J; R.B. Rucker, D.B. McCormick, J.W. Suttie (2007). Handbook of vitamins (4th ed.)

EGGSHELLS:

“An eggshell is the outer covering of a hard-shelled egg and of some forms of eggs with soft outer coats. Bird eggshells contain calcium carbonate and dissolve in various acids, including the vinegar used in cooking. While dissolving, the calcium carbonate in an egg shell reacts with the acid to form carbon dioxide.

The bird egg is a fertilized (or, in the case of some birds (such as chickens) possibly unfertilized) gamete located on the yolk surface and surrounded by albumen, or egg white. The albumen in turn is surrounded by two shell membranes (inner and outer membranes) and then the eggshell. The chicken eggshell is 95-97% calcium carbonate crystals, which are stabilized by a protein matrix.[2][3][4] Without the protein, the crystal structure would be too brittle to keep its form and the organic matrix is thought to have a role in deposition of calcium during the mineralization process.[5][6][7] The structure and composition of the avian eggshell serves to protect the egg against damage and microbial contamination, prevention of desiccation, regulation of gas and water exchange for the growing embryo, and provides calcium for embryogenesis. Eggshell formation requires gram amounts of calcium being deposited within hours, which must be supplied via the hen’s diet.[4]

The fibrous chicken shell membranes are added in the proximal(white) isthmus of the oviduct.[4] In the distal (red) isthmus mammillae or mammillary knobs are deposited on the surface of the outer membrane in a regular array pattern.[8][9] The mammillae are proteoglycan-rich and are thought to control calcification. In the shell gland (similar to a mammalian uterus), mineralization starts at the mammillae. The shell gland fluid contains very high levels of calcium and hydrogen carbonate. The thick calcified layer of the eggshell forms in columns from the mammillae structures, and is known as the palisade layer. Between these palisade columns are narrow pores that traverse the eggshell and allow gaseous exchange. The cuticle forms the final, outer layer of the eggshell.[10]

While the bulk of eggshell is manate, it is now thought that the protein matrix has an important role to play in eggshell strength.[11] These proteins affect crystallization, which in turn affects the eggshell structure. Moreover, the concentration of eggshell proteins decreases over the life of the laying hen, as does eggshell strength.

In an average laying hen, the process of shell formation takes around 20 hours. Pigmentation is added to the shell by papillae lining the oviduct, coloring it any of a variety of colors and patterns depending on species. Since eggs are usually laid blunt end first, that end is subjected to most pressure during its passage and consequently shows the most color.”

http://www.ncbi.nlm.nih.gov/pubmed/10901204

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2005000200001&lng=en&nrm=iso&tlng=en

Nys, Yves; Gautron, Joël; Garcia-Ruiz, Juan M.; Hincke, Maxwell T. (2004). “Avian eggshell mineralization: biochemical and functional characterization of matrix proteins”. Comptes Rendus Palevol 3: 549–62.

http://www.xray.cz/epdic/abstracts/293.htm

http://ag.ansc.purdue.edu/poultry/multistate/koelkebeck1.htm

Hunton, P (2005). “Research on eggshell structure and quality: an historical overview”. Revista Brasileira de Ciência Avícola 7: 67–71.

PLASTIC:

“A plastic material is any of a wide range of synthetic or semi-synthetic organic solids that are moldable. Plastics are typically organic polymers of high molecular mass, but they often contain other substances. They are usually synthetic, most commonly derived from petrochemicals, but many are partially natural. Most plastics contain organic polymers. The vast majority of these polymers are based on chains of carbon atoms alone or with oxygen, sulfur, or nitrogen as well. The backbone is that part of the chain on the main “path” linking a large number of repeat units together. To customize the properties of a plastic, different molecular groups “hang” from the backbone (usually they are “hung” as part of the monomers before the monomers are linked together to form the polymer chain). The structure of these “side chains” influence the properties of the polymer. This fine tuning of the properties of the polymer by repeating unit’s molecular structure has allowed plastics to become an indispensable part of the twenty-first century world.”

History of plastic:

“Early plastics were bio-derived materials such as egg and blood proteins, which are organic polymers. Treated cattle horns were used as windows for lanterns in the Middle Ages. Materials that mimicked the properties of horns were developed by treating milk-proteins (casein) with lye. In the 1800s the development of plastics accelerated with Charles Goodyear’s discovery of vulcanization as a route to thermoset materials derived from natural rubber. Many storied materials were reported as industrial chemistry was developed in the 1800s. In the early 1900s, Bakelite, the first fully synthetic thermoset was reported by Belgian chemist Leo Baekeland. After the First World War, improvements in chemical technology led to an explosion in new forms of plastics. Among the earliest examples in the wave of new polymers were polystyrene (PS) and polyvinyl chloride (PVC). The development of plastics has come from the use of natural plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural materials (e.g., rubber, nitrocellulose, collagen,galalite) and finally to completely synthetic molecules (e.g., bakelite, epoxy, Polyvinyl chloride).

The properties of plastics are defined chiefly by the organic chemistry of the polymer such as hardness, density, and resistance to heat, organic solvents, oxidation, and ionizing radiation. In particular, most plastics will melt upon heating to a few hundred degrees celsius.[18] While plastics can be made electrically conductive, with the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[19] they are still no match for most metals like copper which have conductivities of several hundreds kS/cm.

Thermoplastics can be remelted and reused, and thermoset plastics can be ground up and used as filler, although the purity of the material tends to degrade with each reuse cycle. There are methods by which plastics can be broken back down to a feedstock state.

The greatest challenge to the recycling of plastics is the difficulty of automating the sorting of plastic wastes, making it labor intensive. Typically, workers sort the plastic by looking at the resin identification code, although common containers like soda bottles can be sorted from memory. Typically, the caps for PETE bottles are made from a different kind of plastic which is not recyclable, which presents additional problems to the automated sorting process. Other recyclable materials such as metals are easier to process mechanically. However, new processes of mechanical sorting are being developed to increase capacity and efficiency of plastic recycling.

While containers are usually made from a single type and color of plastic, making them relatively easy to be sorted, a consumer product like a cellular phone may have many small parts consisting of over a dozen different types and colors of plastics. In such cases, the resources it would take to separate the plastics far exceed their value and the item is discarded. However, developments are taking place in the field of active disassembly, which may result in more consumer product components being re-used or recycled. Recycling certain types of plastics can be unprofitable, as well. For example, polystyrene is rarely recycled because it is usually not cost effective. These unrecycled wastes are typically disposed of in landfills, incinerated or used to produce electricity at waste-to-energy plants.

A first success in recycling of plastics is Vinyloop, a recycling process and an approach of the industry to separate PVC from other materials through a process of dissolution, filtration and separation of contaminations. A solvent is used in a closed loop to elute PVC from the waste. This makes it possible to recycle composite structure PVC waste which normally is being incinerated or put in a landfill. Vinyloop-based recycled PVC’s primary energy demand is 46 percent lower than conventional produced PVC. The global warming potential is 39 percent lower. This is why the use of recycled material leads to a significant better ecological footprint.[33] This process was used after the Olympic Games in London 2012. Parts of temporary Buildings like the Water Polo Arena or the Royal Artillery Barracks were recycled. This way, the PVC Policy could be fulfilled which says that no PVC waste should be left after the games.[34]

In 1988, to assist recycling of disposable items, the Plastic Bottle Institute of the Society of the Plastics Industry devised a now-familiar scheme to mark plastic bottles by plastic type. A plastic container using this scheme is marked with a triangle of three “chasing arrows”, which encloses a number giving the plastic type:

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of being shaped or molded, from πλαστός (plastos) meaning molded.[36][37] It refers to their malleability, or plasticity during manufacture, that allows them to be cast, pressed, or extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and much more.

The common word plastic should not be confused with the technical adjective plastic, which is applied to any material which undergoes a permanent change of shape (plastic deformation) when strained beyond a certain point. Aluminum which is stamped or forged, for instance, exhibits plasticity in this sense, but is not plastic in the common sense; in contrast, in their finished forms, some plastics will break before deforming and therefore are not plastic in the technical sense.”

Entomology:

“The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of being shaped or molded, from πλαστός (plastos) meaning molded.[36][37] It refers to their malleability, or plasticity during manufacture, that allows them to be cast, pressed, or extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and much more.

The common word plastic should not be confused with the technical adjective plastic, which is applied to any material which undergoes a permanent change of shape (plastic deformation) when strained beyond a certain point. Aluminum which is stamped or forged, for instance, exhibits plasticity in this sense, but is not plastic in the common sense; in contrast, in their finished forms, some plastics will break before deforming and therefore are not plastic in the technical sense.”

http://plastics.americanchemistry.com/Life-Cycle

http://dwb.unl.edu/Teacher/NSF/C06/C06Links/qlink.queensu.ca/~6jrt/chem210/Page3.html

http://www.infoplease.com/encyclopedia/science/plastic-composition-types-plastic.html

http://link.springer.com/article/10.1007%2FBF00114555

http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0057%3Aentry%3D%2383506&redirect=true

http://www.pcn.org/Technical%20Notes%20-%20Periodic%20Table%20of%20Polymers.htm

SOUND:

“Sound is a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing. The perception of sound in any organism is limited to a certain range of frequencies. For humans, hearing is normally limited to frequencies between about 20 Hz and 20,000 Hz (20 kHz),[3] although these limits are not definite. The upper limit generally decreases with age. Other species have a different range of hearing. For example, dogs can perceive vibrations higher than 20 kHz, but are deaf to anything below 40 Hz. As a signal perceived by one of the major senses, sound is used by many species fordetecting danger, navigation, predation, and communication. Earth’s atmosphere, water, and virtually any physical phenomenon, such as fire, rain, wind, surf, or earthquake, produces (and is characterized by) its unique sounds. Many species, such as frogs,birds, marine and terrestrial mammals, have also developed special organs to produce sound. In some species, these produce song and speech. Furthermore, humans have developed culture and technology (such as music, telephone and radio) that allows them to generate, record, transmit, and broadcast sound. The scientific study of human sound perception is known as psychoacoustics.

The mechanical vibrations that can be interpreted as sound are able to travel through all forms of matter: gases, liquids, solids, and plasmas. The matter that supports the sound is called the medium. Sound cannot travel through a vacuum.

The speed of sound depends on the medium the waves pass through, and is a fundamental property of the material. In general, the speed of sound is proportional to the square root of the ratio of the elastic modulus (stiffness) of the medium to its density. Those physical properties and the speed of sound change with ambient conditions. For example, the speed of sound in gases depends on temperature. In 20 °C (68 °F) air at sea level, the speed of sound is approximately 343 m/s (1,230 km/h; 767 mph) using the formula “v = (331 + 0.6 T) m/s”. In fresh water, also at 20 °C, the speed of sound is approximately 1,482 m/s (5,335 km/h; 3,315 mph). In steel, the speed of sound is about 5,960 m/s (21,460 km/h; 13,330 mph).[6] The speed of sound is also slightly sensitive (a second-order anharmonic effect) to the sound amplitude, which means that there are nonlinear propagation effects, such as the production of harmonics and mixed tones not present in the original sound (see parametric array).

Noise is a term often used to refer to an unwanted sound. In science and engineering, noise is an undesirable component that obscures a wanted signal.

Equipment for outputing or generating : musical instrument, sound box, hearing phones, sonar systems, sound reproduction, and broadcasting equipment. Many of these use electro-acoustic transducers for input : microphones .”

http://web.archive.org/web/20080625012016/http://www.bartleby.com/61/65/S0576500.html

http://www.jhu.edu/virtlab/ray/acoustic.htm

http://books.google.com/books?id=RUDTFBbb7jAC&pg=PA248

http://apod.nasa.gov/apod/ap070819.html

http://www.fluids.eng.vt.edu/msc/gallery/conden/mpegf14.htm

http://library.thinkquest.org/19537/Physics4.html

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s