The term AM encompasses many other manufacturing technologies like 3D Printing, Rapid Prototyping (RP), Direct Digital Manufacturing (DDM), layered manufacturing and additive fabrication.

The reason AM is considered revolutionary, is because of its ease of use. People have the opportunity to buy a 3D printer, and create simple household objects such as cutlery and and other utensils, or any other article which is regularly used. Although one may argue that this method is quite expensive (as of now), it can be surely said that at the rate at which technology is currently advancing, the cost factor will be overcome quite soon.

The applications of AM are limitless. While initially it had been used to make pre-production visualization models, currently it is also used to make end-use products for aircrafts, automobiles, for dental and medical implants, and even fashion products.In fact, for the production of small parts which requires high precision and accuracy, AM is preferred over other methods.

Currently, AM is still in its infancy. With new inventions and breakthroughs, AM will hopefully become much more cheaper and accessible, as well as much more versatile, even to the extent of being used to make synthetic human tissue.

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Pradyumna Chakraborty (f2015551)

Manish Rudraraju (f2015329)

Alekhya Suma K (f2015574)

3D printing, also known as Additive Manufacturing (AM) is a modern manufacturing process which primarily consists of a 3D printer depositing materials – powders, liquids or even living cells, in layers, to produce the final product. It consists of many processes, most important being Computer Aided Design (CAD). 3D printing was first invented by Charles Hull. He also founded the company 3D Systems, which developed the first 3D printer. While initially an expensive process, with the development of technology and advent of open source 3D printers like Fab@Home and RepRap, 3D printing costs have gone down by substantially.

Alongwith with the general advantages of 3D printing like customizability, efficient production and more, there are also some very useful applications of 3D printing in the department of medical sciences. These include, but are not limited to : generation of customized implants and prostheses, producing personalized drug doses and complex drug-release profiles, and in the future, generation of synthetic tissue and organs. It is also used for preparing anatomical models for pre-surgery planning. However, considering that the technology is still in its infancy, it will need to evolve more to be truly useful in the field of medicine, and for that it will need to overcome barriers like patent and copyright concerns, regulatory concerns, safety and security measures, and such.

Additive manufacturing commonly known as 3D printing, though an already advanced technique, is expected to have more applications in future. Therefore a lot of research is being done to improve the quality of the products manufactured.

Porous structures hold unique physical properties (mechanical, thermal and electrical) that are related to their low density and architecture. A critical aspect in optimizing these production techniques and their post-production treatments is to control the morphological and mechanical properties from design up to the final manufactured functional structures.

The general purpose of this study was to develop a strategy to produce, using SLM and post-production surface treatment, customized AM porous structures with a minimized and homogenous surface roughness and overall morphology. Apart from the macro-morphological properties, obtaining a desired surface quality for manufactured parts is one of the biggest SLM challenges. However, none of the proposed strategies allow production of 3D porous structures with a controlled surface roughness. Therefore, there is still a need for a robust surface post-production treatment strategy to obtain a controllable surface quality applicable for complex geometries. Chemical etching in combination with heat treatment improves the surface quality of Ti implants produced by SLM. However one drawback is the fact that the post-production surface treatment often significantly changes the geometry of the manufactured structure compared to its computed aided design (CAD) based definition.

It was shown that there are two mechanisms that significantly increase the surface roughness of objects manufactured by SLM: (i) staircase formation and (ii) the attachment of the powder particles. Surface treatments are used to reduce these effects. However the applied surface treatment should be specifically optimized for each design. In this study, factorial analysis revealed that the concentration of the chemical etching solution and the treatment duration strongly influenced the roughness reduction. It was observed that by increasing the designed beam thickness, a smaller reduction of the final surface roughness was obtained. Based on the DoE output, it was concluded that the designed beam thickness and the CHE solution were the most significant factors influencing surface roughness and beam thickness reduction. It can be expected that an appropriate surface post-treatment would enhance the surface quality and, hence, improve the final functional outcome of the structures. The prediction of DoE indicated that a beam thickness of 140 μm was the most optimal design to finally obtain structures with the desired morphology comparable to that of the reference material. The overall good agreement between the predicted and actual morphological properties of customized structures implies a high reliability of the DoE model predictions for a controlled surface treatment. Apart from biocompatible morphological properties, implant materials are expected to possess optimal mechanical properties. Methods to make the mechanical properties more optimal are still being researched.

Additive manufacturing technologies

Bio medical metal materials with high corrosion resistance, strength and toughness are widely used for bone surgery and dental implant materials. Most metal implants used for clinical practice are fully dense, but their elastic moduli are obviously higher than that of bony tissues. But this may lead to stress shielding between implants and bones. The

elastic modulus of porous metals is lower than that of dense metals. By adjusting the pore parameters, the elastic modulus of the porous metals can be made to match that of the bone tissues. This may even facilitate for bone ingrowth through the pores, which improves the bonding between bone and the implants. For the bone repair implants, the size varies from one person to another, the shape is complicated and full of tiny details, making it difficult to flexibly control pore structure and liberally manufacture implants by considering different bone defect forms. Here comes the application of additive manufacturing technologies like selective laser melting (SLM) and electron beam melting technology (EBM).

Pore structure is the key factor for mechanical compatibility and biocompatibility of bone implants with the host bone. A porous Ti6Al4V acetabulum cup implant with “a porous surface and a dense inner layer structure” fabricated by EBM has been successfully applied in clinical practice. A report on the Ti6Al4V dental implant with a porous surface and a dense inner layer structure, using the SLM method showed that the rough surface of the implant is good for new bone ingrowth, and thus improves the connection strength between the implant and alveolar bone. Recently an opening cup implant sample with different pore dimensions and porosity made with Ti6Al4V alloy was prepared using the EBM process. A porous titanium implant with diamond molecular structure was fabricated using the EBM process which was coated with a tantalum film using the Chemical Vapor Deposition (CVD) method as a result of which the porous titanium implant simultaneously has the combination of excellent mechanical performance and biological properties.

The process of forming implants is done in the following steps:

1) The defective bone undergoes a CT scan layer by layer.

2)An image processing software, like Mimics, is used which translates the CT layer scanning image data into CAD/CAM data format for manufacturing of the defective bone parts and can be shown as shown in highly accurate 3D model for design purposes.

Conclusion:

In these new developing additive manufacturing technologies of SLM and EBM, some problems still exist which urgently need to be solved. Therefore, further in-depth and meticulous research in terms of preparation of porous metal implants should be considered.

Ti6Al4V is used in implants

1) What is 3D printing?

A: This is the first question that came to my mind. I read in the article’s introduction that 3D printing, also known as Additive Manufacturing (AM), Rapid Prototyping(RP), or Solid Free-form technology (SFF),  is the process of deposition of layers of raw materials, like wood dust, plastic, glass, and in the future, probably even synthetic living tissue, in order to make a final finished product. It includes generation of a CAD (Computer Aided Design) file containing 3D data about the product to be made, and then feeding this data into a 3D printer to produce the final product.

2) Who invented 3D printing?

A: 3D printing was invented by Charles Hull, who called it “Stereolithography”, while working on making plastic products from photopolymers. Stereolithography stored CAD data in an .stl file format, and communicated these instructions electronically to the 3D printer. In fact, he also founded the company 3D Systems, which developed the first 3D printer, called “stereolithography apparatus”. It also produced the first commercial 3D printer, the SLA-250.

3) How expensive is this 3D printing?

A: While 3D printing initially had been quite expensive, currently, due to great advances in technology and advent of open source 3D printers, costs have gone down a lot. Simple 3D printers now cost only as much as 300 to 400 dollars, which is a low cost compared to their usefulness.

4) What are the different types of 3D printers?

A: Some commonly used types of 3D printers are:

a) Selective Laser Sintering (SLS) – It uses powdered raw materials, on which a laser draws the shape of the product, fusing it together. Then a new layer of powder is laid down, and this process is repeated.

b) Thermal Inkjet Printing (TIJ) – This technique uses thermal, electromagnetic, or piezoelectric technology to deposit tiny droplets of “ink” onto a substrate according to digital instructions. In TIJ printers, printhead creates small air bubbles which on collapsing, produce small pressure pulses that eject very small amounts of ink. Due to their benign effect on mammalian cells, it is already being applied to print simple 2D and 3D tissues and organs (bioprinting).

c) Fused Deposition Modeling (FDM) – FDM printers are much more inexpensive than SLS type, but work on the same principle. However, instead of ink, beads of heated plastic are used.

5) What are the main applications of 3D printing for medical sciences?

A: Currently the 3D printing process is of great importance in the medical industry due to its ability to produce customized products, and its efficiency of production. It is used for bioprinting tissues and organs (mostly using TIJ printers), creating customized drug doses, making complex drug-release mechanisms, and creating personalized drug delivery systems. Another major use is making custom implants and prostheses.

6) Given the fact that 3D printing can be used to produce artificial tissues, how much of an impact will this make in future?

A: 3D printing, due to its accuracy and customizability, is a very suitable method for making synthetic tissue. In future, it may be very well possible for stem cells to be extracted from a child’s baby teeth, and then using these to produce personalized organs for transplant. This would effectively do away with the problem of organ rejection after a transplant. In situ bioprinting, which would consist of tissues being directly printed on the human body, is also a possibility. It would be enough for a patient to take a single pill per day for all his/her ailments. Even production of synthetic neural matter, in order to replace that damaged in any accidient or otherwise, is possible. All of these are currently either impossible, or are not practically feasible. So, if 3D printing is able to make these predictions true, then it will probably form an integral part of the medical industry.

7) What are the problems that 3D printing has to overcome in the future?

A: There are quite a lot of concerns over 3D printing in medical industry. The first is the moral or ethical concern about a machine producing live tissue. This further leads to unnecessary hype and exaggeration about 3D printings capabilities. The patent, copyright, and regulatory concerns are also present. Finally there is a thought about safety and security, as 3D printers have also been used by criminals, often for illegally creating weapons. There is also the risk of mass production of counterfeit medications and drugs.

A: The earliest 3D printing technologies first became visible in the late 1980’s, at which time they were called Rapid Prototyping (RP) technologies. This is because the processes were originally conceived as a fast and more cost-effective method for creating prototypes for product development within industry.

2. Who got the first patent for additive manufacturing?

A: The first patent application was filed by Dr Kodama in Japan, in 1980.

However the first patent for stereolithography apparatus (SLA) was issued to Charles Hull in 1983. He co-founded the  3D Systems Corporation — one of the largest and most prolific organizations operating in the 3D printing sector today.

3. Why is Ti6Al4V used mostly in this field?

A: 3D printed Ti6Al4V is widely used among advanced aerospace applications. Its adoption is particularly favored by its exceptionally high strength-to-weight ratio and resistance to fatigue. Moreover, Ti6Al4V presents an excellent resistance to corrosion (in aqueous solutions, oxidizing acids, chlorides, rocket propellants and alkalis) and to temperature.

4. What is staircase effect?

A: The staircase effect, caused by the stepped approximation by layers of curves and inclined surfaces of the manufactured object, is a common problem in AM processes influencing the surface roughness, but, also, the final structure thickness of the manufactured objects. Additionally, the staircase effect enhances the powder particle attachment to the beam bottom section, which introduces the heterogeneity of the surface topology of the SLM manufactured objects.

5. What do you mean by the in vivo and in vitro experiments in 3D printing?

A: They are biological experiments which might use 3D printing .

In vivo experiments: They refer to the experiments in which the effects of various biological entities are tested on whole, living organisms usually animals including humans.(In vivo means "within the living".)

In vitro experiments: They refer to the experiments that are performed with cells or biological molecules studied outside their normal biological context. (In vitro means "within the glass".)

1)What is the basic area of application of metal implants?

A: When there is a bone defect in a person's body, metal implants are used to repair the defects. For example, when a particular bone gets worn out, an implant may be used to prevent further damage and it may also promote bone ingrowth.

2) What are the various additive manufacturing techniques used for fabricating metal implants?

A: Two basic additive manufacturing techniques used are Selective Laser Melting (SML) and Electron Beam Melting (EBM) technologies.

3) What are the properties required for the materials used for fabricating metal implants?

A:. Additive manufacturing has special requirements for the metal powder, such as small particle size, narrow particle size distribution, high sphericity, good liquidity, and low oxygen content. At present, only Ti6Al4V, CP-Ti, In625, CoCrMo, and 316L are available on the market, though Ti6Al4V is the one mostly used.

4) How are the metal implants fabricated?

A:The basic process of fabricating the metal implants is as follows:

a)The defective bone undergoes a CT scan layer by layer.

b)An image processing software, like Mimics, is used which translates the CT layer scanning image data into CAD/CAM data format for manufacturing of the defective bone parts and can be shown as shown in highly accurate 3D model for design purposes.

5)Why are porous metal implants preferred over dense metal implants ?

A: Most metal implants used for clinical practice are fully dense, but their elastic moduli are obviously higher than that of bony tissues. But this may lead to stress shielding between implants and bones. The

elastic modulus of porous metals is lower than that of dense metals. By adjusting the pore parameters, the elastic modulus of the porous metals can be made to match that of the bone tissues. This may even facilitate for bone ingrowth through the pores, which improves the bonding between bone and the implants.

I had got my main source file from the site http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4189697/ .  I had also used the BITS Library Online Public Access Catalogue Site (http://libraryopac.bits-hyderabad.ac.in/), browsed  a few videos on YouTube (www.youtube.com), and had read many articles on different websites on 3D printing in general, and on medical applications of 3D printing.

Your discussions are interesting and so are the questions you have out forth. 

Manish, do you think you that your part on how you collected data can be improved? Please, make an attempt on revising and editing the part again.

• Next-generation biomedical implants using additive manufacturing of complex, cellular and functional mesh arrays(L. E. Murr, S. M. Gaytan, F. Medina, H. Lopez, E. Martinez, B. I. Machado, D. H. Hernandez, L. Martinez, M. I. Lopez, R. B. Wicker and J. Bracke).  Site:  http://www.jstor.org/stable/25663354 
• Printing Organs, Prosthetics & Devices : Medical 3D Printing Comes of Age. Site: https://ssl.www8.hp.com/hpmatter/issue-no-3-winter-2015/printing-organs-prosthetics-devices-medical-3d-printing-comes-age 
• Lee Cronin : Print your own medicine (TED Talk). Site: https://www.youtube.com/watch?v=mAEqvn7B2Qg
• 3D printing to make next-gen pacemaker. Site: http://news.stlpublicradio.org/post/wash-u-u-i-scientists-use-3-d-printer-help-create-prototype-next-gen-pacemaker
• Anthony Atala : Printing a human kidney (TED Talk). Site: http://www.ted.com/talks/anthony_atala_printing_a_human_kidney?language=en
• 3D Printed Prosthetic Hand. Site: https://www.youtube.com/watch?v=6dI-dNE2yQ0
• 3D Printed Biopolymers for Tissue Engineering Application. Site: http://www.hindawi.com/journals/ijps/2014/829145/
• 3D Printing for Medical Device Industry. Site: http://www.tcs.com/SiteCollectionDocuments/White%20Papers/3D-Printing-New-Opportunities-for-Medical-Device-Industry_0315-1.pdf

Arcam Company independently developed the earliest EBM for commercial use in the world.

Now that a pie chart has pop ed up ; could each one of you discuss what sort of information is best suited to be depicted a pie chart, line graph, bar chart ?

The main source of my information is my article (that I found in BITS Library):http://www.foundryworld.com/uploadfile/2014090238458693.pdf

These are the various links of the sources of information that I found on the web:

1) EBM vs SLM (a presentation) :http://www.slideshare.net/carstenengel/selective-laser-melting-versus-electron-beam-melting

2) Next generation orthopedic implants using additive manufacturing (a research article):http://www.hindawi.com/journals/ijbm/2012/245727/

3) Source of the post regarding the ATMOS T-shirt (a facebook post on the group BPHC Shout Boxx..) : https://www.facebook.com/groups/bphcshoutbox/?fref=ts

The links to the YouTube videos I watched:

1)Arcam Electron Beam Melting: https://www.youtube.com/watch?v=A4lm_CgISnA

2) 3D printed dental abutments: https://www.youtube.com/watch?v=ApWjOfcUlzk&list=PLhdh_20l2PtqnQL_Uz6BTUDCeSUnYBAKr&index=16

3) Metal- on- Metal hip replacement animation: https://www.youtube.com/watch?v=GGL1h99xPGc

4)Electron Beam Machining compilation: https://www.youtube.com/watch?v=jbY-tOcI2tM

5) Printing Bones: https://www.youtube.com/watch?v=-ZUk2Ppta-g

6) Trabecular metal dental implant: https://www.youtube.com/watch?v=ptzQ1Qz-MdM

Sources of the images that I posted:

1) Breakeven analysis comparing conventional and additive manufacturing processes: http://dupress.com/articles/dr14-3d-opportunity/

2) Selective Laser Sintering: https://en.wikipedia.org/wiki/Selective_laser_sintering

3) Pie chart regarding various applications of additive manufacturing: https://www.google.co.in/search?q=applications+of+additive+manufacturing&rlz=1C1TSND_enIN641IN641&espv=2&biw=1366&bih=599&source=lnms&tbm=isch&sa=X&ved=0CAcQ_AUoAmoVChMIi4PuuJ6cyAIVQ1mOCh0N5A_9

4) Acetabular cup implant for femoral bone: https://www.google.co.in/search?q=acetabular+cup+implant+for+femoral+bone&rlz=1C1TSND_enIN641IN641&es_sm=93&source=lnms&tbm=isch&sa=X&ved=0CAcQ_AUoAWoVChMIzP2n-p6cyAIVi8GOCh20-QWK&biw=1366&bih=599

1. My article ( Surface Roughness and Morphology customization of additive manufactured open porous Ti6Al4V): http:// href="http://www.mdpi.com/1996-1944/6/10/4737/PDF">www.mdpi.com/1996-1944/6/10/4737/PDF.

2. "Journal of Achievements in Materials and Manufacturing Engineering" (Volume 30, Issue 2):

http://www.journalamme.org/papers_vol30_2/3023.pdf

3. An article that is related to mathematical modelling of additive manufacturing: http://www.iaeng.org/publication/WCE2014/WCE2014_pp1404-1409.pdf

Some videos on Titanium 3D printing in implants and other fields; decreasing surface roughness:

4. A video on Titanium 3D Printing:

https://www.youtube.com/watch?v=E7--ZWPVVdQ

5. Layer wise metal additive manufacturing:

https://www.youtube.com/watch?v=0nk8wOJQViM

6. Post processing in 3D Printing:  https://www.youtube.com/watch?v=Bc-zTKs4_1Y

7. Improving the finish on 3D prints:

https://www.youtube.com/watch?v=AoMH2z2O4Ys

The following helped me clear my doubts and also know more about my topic:

8.  http://3dprintingindustry.com/3d-printing-basics-free-beginners-guide/history/

9.  https://www.additively.com/en/material/from/slm-solutions/slm-solutions-ti6al4v

10.  http://www.farinia.com/additive-manufacturing/3d-materials/how-can-aerospace-benefit-from-3d-printed-titanium-Ti6Al4V

11.  http://www.slideshare.net/FariniaGroup/3d-printed-titanium-ti6al4v-for-aerospace-additive-manufacturing

12.  http://www.optomec.com/3d-printed-metals/lens-emerging-applications/medical-implants/

Eg:

1) What is additive manufacturing to you?

a) An art

b) A medical solution in the field of prosthesis

C) Engineering

So, children work on the questions again! But good attempt. Please have a look at the sample on the CMS.

Target audience: General public

This survey is to check the general awareness about additive manufacturing in public.

1. Do you think that 3D printing is going to become a major part of human life in the near future?

• Yes
• No
• It's too early to say something

2. How important is the role that additive manufacturing plays in medical implants?

• It is a great idea to introduce synthetic parts which actually do the functions of  the original. 
• It may perform their functions up to some extent but it is still a foreign body to  human.

3. How much difference, according to you, would 3D printed food make in the hygiene of food?

• It would definitely lead to more hygienic conditions when it comes to food.
• So far additive manufacturing has been used only to print food which is not  very healthy, so I don’t think it’s going to change anything.
• I never heard about 3D printed food.

4. What do you have to say about the cost effectiveness of additive manufacturing?

• The cost of additive manufacturing is quite reasonable keeping in mind the  changes it can bring to our lifestyle.
• It is too costly for common man to afford.

In addition, add a statement as to why you are taking the survey, for the benefit of the person who is answering.

Good!

• Rapid Prototyping (RP) and Solid Free-Form Technology (SFF) -> Synonyms for additive manufacturing.
• Stereolitholgraphy -> Charles Hull, who first invented 3D printing, called it stereolithography.
• Open-source ->Denotes software for which the original source code is made freely available and may be redistributed and modified.
• Bioprinting -> Thermal Inkjet Printing (TIJ), due to its negligible effect on living cells, is used to print simples 2D and 3D tissues and organs. This is known as Bioprinting.
• Craniofacial -> Relating to the cranium and face.
• Perfusable -> Permeable or suffusable with a liquid, color, quality, etc.
• Maxillofacial -> Of or relating to the jaws and face.

• Morphology: The study of form, shape or structure of things in particular.
  
• Proliferation: Rapid increase in the number or amount of something.
• Scaffolding: A temporary structure on the outside of a building, made of wooden planks and metal poles, used by workmen while building, repairing, or cleaning the building.

• Robust: Sturdy in construction.

• Voxel: (in computer-based modelling or graphic simulation) each of an array of elements of volume that constitute a notional three-dimensional space, especially each of an array of discrete elements into which a representation of a three-dimensional object is divided.

• Tomography: Imaging by sections or sectioning, through the use of any kind of penetrating wave.

• Regression: A return to a former or less developed state.

• Micro-graph: A photograph or digital image taken through a microscope or similar device to show a magnified image of an item. This is opposed to a macro-graphic image, which is at a scale that is visible to the naked eye.

• Biocompatibility:  The term refers to the ability of a material to perform with an appropriate host response in a specific situation.
• Stereolithography: It is an additive manufacturing technology to produce products one layer at a time using lithographic methods.
• Laminated Object manufacturing: It is a rapid prototyping system in which layers of laminate are glued together and cut to shape with a knife or laser cutter.
• Selective Laser Sintering: Selective Laser Sintering (SLS) is an additive manufacturing technique that uses a laser as the power source to sinter powdered material, aiming the laser automatically at points in space defined by a 3D model, binding the material together to create a solid structure.
• Chemical Vapour Ceposition: It is a chemical process used to produce high quality, high-performance, solid materials in which the wafer (substrate) is exposed to one or more volatile precursors which react and/or decompose on the substrate surface to produce the desired deposit.
• Osseo Integration:  The term refers to the direct structural and functional connection between living bone and the surface of a load-bearing artificial implant.
• Amyotrophy: The progressive wasting of muscle tissues.
• Osteo-necronics: It is a disease caused by reduced blood in the joints.
• Acetabulum: The acetabulum is a concave surface of the pelvis. The head of the femur meets with the pelvis at the acetabulum, forming the hipjoint.

• Bioprinting of Tissues and Organs – Tissue and organ failure patients will be the people who are most benefitted by this. By using additive manufacturing to mass produce live tissues and functioning organs, the global shortage of donated organs can finally be solved.
• Customized Implants – Another important application of additive manufacturing is production of implants according to the need of the patient. This also cuts down the need of multiple processes like acquiring raw material, carving, transport, and such, as the implant can be directly produced in situ, that is, at the place where the operation will be taking place, thus saving a great deal of time.
• Anatomical models – Accurate anatomical models of different internal organs can be made with 3D printing. This allows for pre-surgical planning, as well as provides a great deal of help in teaching about the internal organs. This function could be possibly combined with bioprinting of organs to produce highly precise anatomical bio-models of the human body, which could be used for a variety of purposes.
• Customized drug dosage and delivery devices – 3D printing can be used to create custom made, need-based drug doses, and methods for consumption of drugs and other medicines. This may be helpful for those who have problems with the normal methods of drug consumption, or have side effects with the normal doses.
• Complex drug release profiles – Additive manufacturing allows for the creation of unique methods of drug release within the body. This will help those who have problems with the conventional methods of drug release.

Additive manufacturing can be used in the field of metal implants to fabricate fully additive manufactured bones or metal implants. By looking at the usage of additive manufacturing in the medical field, it looks that it won't be wrong to think that additive manufacturing is going to be extensively used to fabricate metal implants and possibly, prosthetic bones that would help repair the bone defects of a large number of people in the future. This looks even more more possible due to its cost- effectiveness; even the common man would be able to afford a resurrection from their bone defects.

Therefore, we suggest fabricating artificial bones out of additive manufacturing as our highly probable visionary in the field of additive manufacturing.

Now you've got all information you need for your test 2 ;-).

You can take a print out of the padlet. Its downloadable in the PDF form.