The purpose of the presentation is to show the evolution of the

Document Sample
The purpose of the presentation is to show the evolution of the Powered By Docstoc
					Jeff Jong
Arul Krishan
Liz Hulsey
Ray Chung

               Waste Management in Space

       The Space Program has changed quite a bit in the past few decades and the waste

management system is no different, evolving from what now is considered a primitive

disposal systems meant for short-term missions to more and more advanced and high-

tech systems that have long-term space flight, such as a mission to Mars, in mind. Just as

with any space-related topic, the issue of microgravity comes up with waste management

as well.

           It‟s amazing how much our bodies and everyday lives depend on gravity. For

example, in a microgravity environment defecation becomes a much more difficult and

complicated task than it is here on earth. Our paper will get into more detail regarding

this topic later; however, just for a gist of things and something to think about(too much

jargon, we are writing here, not talking): it requires somewhere around 45 minutes for an

astronaut to go through the process of defecation and cleanup in space, a significant

change in time compared to that here on earth. Another annoying consequence of

microgravity is that wipes(what are wipes) occupy up to 3 times as much space as they do

here on earth, which leads to a buildup of waste if not dealt with properly as one can

imagine. Also in space urination volumes tends to increase; therefore, an appropriate

containment and disposal system must be put in place to take into account this increase in

volume. The need for this system has risen significantly in years since it is no longer

economical to bring back all of the waste from a space mission back to earth, especially

since long-distance space missions are looking more and more like a reality. In our

paper, we hope to address all these issues as well as giving a general history and

evolution of the waste management system during EVAs and in the shuttle as well.
INTROuction: The function of the waste management system (WMS) is to organize the

disposal and recycling of solid and liquid wastes. The basic requirements of the system

include the collection and stowage of feces, the collection and recycling of urine, and the

removal of urine from the pressure garment assembly. The waste management system

consists of a urine subsystem and a fecal subsystem. Starting first with the urine

subsystem, the principal elements are the urine receptacle assembly (URA), the urine

transfer system (UTS), the urine collection and transfer assembly, (UCTA), and special

urine collection devices that are used to collect samples for postflight analysis. The most

important component of this subsystem is the recycling of the water in urine. If it is not

obvious, one just has to think about it for a few moments and realize(jargon) that since

resources are scarce during space missions, everything needs to be conserved and reused

if possible. This is no different with water, and considering that water is one of the most

used and necessary resource for the sustenance of human life it is very important that if

transportation of needed water is not economical, then a reliable recycling system must

be put in place. Therefore, every drop of water, even the water in waste materials, must

be reused in the spacecraft as well as during EVAs, which we will go into further detail


         Based on the waste-management system of the Apollo missions, the primary

means of urine purification is by a method that is termed, Multi-filtration. Just as a side

note(stop it!) the Russians also use this „multi-filtration‟ method for their urine

processing. This process is termed multi-filtration (MF) because there are several steps

involved. The first step is termed „pretreatment‟ and is required to stabilize urine for

microbial control. The next step is the distillation/ evaporation process used to lower the
urine‟s salt content. Afterwards OxoneO (a potassium monopersulfate compound) and

sulfuric acid are added to the urine stream in appropriate quantities so that the urine‟s

ammoniated species may be stabilized. This is very important since during urea

hydrolysis, ammonia gas is produced which is poisonous and therefore, must be kept

away from the cabin air.

       Here is a picture of the urine collection device used in Apollo missions:

               After the „pretreatment‟ process is complete, the urine enters the primary

purification system. In most systems used today, the first step involves the removal of

particulate material by some mode of filtration. In the next step, dissolved salts and

organics are removed by absorption onto a combination of ion exchange resins, activated

carbons, and other various media. Alcohol and urea are not effectively destroyed by

adsorption, thus they require additional treatment via catalytic oxidation. Many chemicals

can perform this oxidation step such as PCC (Pyridinium Chlorochromate) or some
Magnesium oxide compound (KMNO4 or MNO2-). The Russians and the Americans

employ slightly different techniques in this final oxidation step. The Russian system uses

ambient temperature catalysts, whereas the Americans use a low-temperature aqueous

phase catalytic oxidation reactor, termed the Volatile Removal Apparatus (VRA).(Good

comparison) (So, can you drink the water now? Is this the entire process?) Another

system that is currently being tested in parallel to Multi-filtration is the vapor

compression distillation system (VCD). The VCD processes pretreated urine and flush

water by a phase change process. The original stream of pretreated urine is evaporated at

low pressure to form water vapor and then the vapor is compressed in order to increase its

pressure and condensation temperature. The vapor is then redirected to the condenser

where the vapor condenses and produces latent heat, which is transferred to provide heat

for evaporation. In order to measure the water‟s purity, the VCD contains a conductivity

sensor that measures the conductivity of the product water. If its conductivity exceeds

120 mmho/cm, the water goes through another cycle of purification in the VCD.

Concentrate and other pollutants are collected in a tank within the VCD. See Appendix D

for schematic.

Urination Time and Flow Rate Chart: (What is this? Why don’t you talk about it?)
       Equipment used prior to the Apollo missions functioned very similarly to the ones

used during the Apollo missions with a few minor design changes. Before the start of

Apollo 12, the astronauts utilized the urine transfer system (UTS). The urine transfer

system consists of a roll-on cuff, a receiver, a valve with a manifold, a collection bag, and

a quick-disconnect fitting. The roll-on cuff was a rubber tube that functioned as an

external catheter between the penis and the receiver/valve. The cuff was designed to be

used for one day (five or six urinations) and was then replaced.

       Beginning with Apollo 12 and missions thereafter, a different system was used

called the urine receptacle assembly (URA). The urine receptacle assembly is an open-

ended, cylindrical container that can be conveniently held. The receptacle is connected by

a quick-disconnect fitting attached to a flexible urine dump line, which in turn is

connected by a quick-disconnect fitting attached to the waste management panel. The

receptacle can accommodate a maximum urine flow of 40 ml per second. The URA

contains a honeycomb cell insert that supports a hydrophilic screen. The honeycomb

insert provides a large contact area that acts as a bundle of capillary tubes. The capillary

action produced by each cell of the honeycomb tends to hold the fluid in place in the

microgravity environment until it can pass into the urine dump line.

       During the Apollo launches, EVAs, and emergencies, the shuttle crew(but Apollo

is not a shuttle) would wear a device known as the urine collection and transfer assembly

(UCTA) (FIG2). The urine collection device accommodated a maximum urine output of

4000mL per person per day with a maximum discharge rate of 800mL per urination and

at a delivery rate of 50mL/sec. The device was worn over the LCG, not the LCVG, since

it did not exist yet.(good insight) The urine collection and transfer assembly is designed
to facilitate urination when crewmen are wearing pressure suits such as during EVAs.

The urine collection and transfer assembly consists of a roll-on cuff and a collection

bladder worn around the waist. The UCTA is worn over the fecal containment garment.

Urine in the device can be drained either while the crewmen are in the suit, or after the

suit is removed by connecting the urine transfer hose to the spacecraft waste management


         The urine transfer hose is made of flexible, convoluted fluorocarbon, which

allows it to withstand the pressure difference between the spacesuit and the spacecraft,

and at same time be supple enough for the astronauts to easily manage during EVAs. The

hose also can be used to join the space suit‟s urine quick-disconnect fitting to the waste

management panel in order to expedite the removal of urine from the collection

assembly. Installed between the waste management panel quick-disconnect fitting and

the hose is a 215-micrometer filter, used as prevention against the clogging of the hose

with use over time. The dump nozzle orifice has a diameter of 0.1397 cm, which restricts

liquid flow to 453.6 gm/minute.
       The Urinary and Transfer Assembly (Yes, I know it is a picture)

       Because no system existed to extract feces from the body, the men had to rely

upon the most basic concept for “inflight fecal collection.” The method involved using

tape to adhere a plastic bag to the buttocks to catch the fecal excretion(when was this?).

The other primary component of the waste management system is the fecal subsystem(Is

this the new system). As stated before, this system usually consists of a fecal collection

assembly, tissue dispensers, a waste stowage compartment, and a waste storage bag. The

fecal collection assembly consists of a fecal bag and an outer fecal/emesis (FE) bag

bound together with a plastic wrapper. The fecal bag is a plastic sack with a flange at the

opening and a finger cot in the center of one side. A stretch of tape is used to attach the

flange to the buttocks. Tissue wipes and a germicide pouch are stored in a pocket on the

outside lower end of the bag. The outer transparent FE bag is used for storing of the used
fecal bag. Internal and external seals at the mouth of the bag make it capable of

containing a 3.4 x 104-N/m2 (5 psi) gas differential pressure. The fecal collection system

generally functions in the following way: The finger cot(what is a finger cot anyway?) is

used to position the fecal bag over the anus. After the astronaut discharges their bodily

waste, the bag is removed from the buttocks, and the anus is cleaned with tissue wipes.

The wipes are also disposed of into the fecal bag. The user secures the germicidal liquid

pouch and cuts the corner off the outer pouch. The user then deposits the germicide into

the outer pouch and seals the bag. The germicidal liquid is often a mixture of sodium

orthophenylphenol and sodium chlorophenylphenol of amaplast blue LXT. The inner

pouch is then ruptured in order to mix the germicide with the wastes. The inner bag is

then placed into the outer bag. The whole thing is then rolled into the smallest possible

volume and then placed in the waste stowage compartment. This compartment features a

split membrane inside the door to prevent fecal bags from floating back out into the cabin

once they had been placed within the compartment.

         During extravehicular activity, a fecal containment system (FCS) is also

employed. This FCD consists of a pair of underpants of absorbent material worn under

the LCVG. If an uncontrolled bowel movement occurs, the underpants will contain the


         Table 2 (SEE APPENDIX B) shows the averages of sample weight of fecal matter

obtained for analysis on the Apollo missions. Carmine red and brilliant blue dyes were

given orally to the subjects for separation of stool periods. Preflight and postflight

collections were carried out using toilet facilities established in the crew quarters and at

various sites where the crew was undergoing training and preparation. Orbital stool
collections were made with specially designed inflight plastic defecation bags. The entire

sample was stored in the cabin without refrigeration but with a mixture of

phenylphenolate derivatives in propylene glycol as a preservative. This data could be

used to analyze the overall diet of the individual, how much water the person is losing per

day, tell if the person has any sickness, etcetera.

       Table 3 (SEE APPENDIX C) contains data that summarizes which devices were

worn during each Apollo mission. The first known spaceflight which involved the usage

of an actual toilet was in 1973 during the age of Skylab. The area was probably as small

as the size of a bathroom stall now and did not include a sink or shower.

Experimental Fecal/Emesis System Flown Aboard Apollo 16

Three modified fecal collection bags were flown to evaluate their performance on the

Apollo 16 mission. The bags were of the same basic design as the Gemini-type(where did

you talk about this?) fecal bag with the following exceptions: (1) a modified seat flange,

for better fit of seat flange to buttocks (this helped with the comfort issue that most

crewmen had with the device); (2) a wider finger cot; and (3) and improved seal for

keeping the device closed during performance of personal hygiene (with the improved

seal, there was less chance of contact with the waste by accidental escape).

Lunar Module Waste Management System

       The Lunar Module waste management system incorporated systems used in the

Command Module. These systems were used in similar fashion in both the Lunar Module

and Command Module. The principal difference was that there was no overboard
dumping of wastes on the lunar surface. The urine subsystem in the Lunar Module

consisted of in-suit urine containers (identical to the Command Module system), a urine

transfer hose, a manually operated waste control valve, and a large (8900 cm3) waste

fluid container. To drain the in-suit device, the waste fluid container was attached to the

in-suit urine container by a urine transfer hose, and the suit was then slightly

overpressurized. Because of a 6.9 x 103-N/m2 (1.0 psi) pressure differential, when the

control valve opened urine flowed from the in-suit container to the waste fluid container

at a rate of approximately 200 cm3/minute. As a backup device, two 900-cm3 waste

containers were provided for direct attachment to the in-suit container. On Apollo 15 and

subsequent missions, a low pressure container was installed in the descent stage of the

Lunar Module. A line interconnected this tank with a urine receiver in the ascent stage.

This receiver was a simple funnel-like receptacle that permitted urine collection without

intimate contact.

       In general, the Apollo waste management system worked satisfactorily from an

engineering standpoint. From the point of view of crew acceptance though, the system

was seen as unsatisfactory. The greatest concern with both the urine and fecal collection

systems was the fact that these required more manipulation than crewmen were used to in

the Earth environment and were, as a consequence, found to be objectionable. The urine

receptacle assembly represented an attempt to preclude crew handling of urine specimens

but, because urine spills were frequent, the objective of "sanitizing" the process was

thwarted. The fecal collection system caused the most distasteful set of problems. The
collection of the feces required much skill to prevent the waste from eluding the

collection bag and consequently soiling the crew, their clothing, or cabin surfaces. The

difficulty of the fecal collection process caused a large consumption of time. An Apollo

7 astronaut required an estimated time of 45 minutes[*] to correctly accomplish the

process. Good placement of fecal bags was difficult to attain; this was further

complicated by the fact that the flap at the back of the constant wear garment created an

opening that was too small for easy placement of the bags.[**] As stated earlier, kneading

of the bags was required to release the germicide within the bag for inactivation of the


         Attempts to improve the fecal collection system, as exemplified by the modified

fecal/emesis collection bags flown on Apollo 16, failed in the crew‟s estimation. During

Postflight debriefings, crew comments indicated that the experimental bag was not

significantly better or easier to use than the baseline Gemini-type bag. Further

development of the bag was, therefore, not pursued.

The Apollo waste management system‟s design and operations pointed to the need for

several improvements in future missions. These were the following:

   1. Future systems should not require intimate contact.

   2. The time required for system use should be significantly reduced.

   3. The waste management system should provide some technique of automatically

         removing feces from the buttocks area.
These considerations were taken into account in the design of the improved Skylab waste

management system.

       Considerations for waste control on EVA and on the ship were the following

during the Skylab period: comfort, user-acceptable (often less intimate contact with the

materials; example to follow in discussing fecal matter containment), be able to last the

duration of EVA (6-8hours), safely be able to use without attendants (no other person

would have to be present as when people originally donned and doffed), ease of use, post

defecation cleansing, volume and mass of body waste products. Defecation is unlikely to

occur so the system should provide urine and menses protection for women, urine support

for men, and containment of defecation in case of diarrheal episodes.

Table 1 (See Appendix A) shows the mass and volumes of everyday human waste


       By analyzing this data, it is very possible to develop the devices necessary to

contain the waste. We must look at the mass and volume of the waste produced to utilize

the proper materials to contain the waste. They must be able to contain the specific

volume particularly. Mass is not such a large concern since microgravity can deal with

the weight in space. Normal fecal bolus of a healthy adult ranges from 4-8 inches long by

.5-1.5 inches in diameter and weighs anywhere from 3.5-7oz.
Figure 4 Urination Time and Flow Rates

*Microgravity tends to increase the volume of urine excreted per day. This means we

should account for the increased volume such that we are not venting urine out of the

shuttle. One of the problems that occurred during the lunar optical experiments was that

the dumped waste tended to form a cloud of vapor around the shuttle that would interfere

with the observations and damage the optical equipment. So to properly develop devices,

we must also consider the physiological changes in flow rate of urine, menses (for

women), size of fecal boluses, the number of times that each person urinates or defecates

to minimize bags required to dump the waste.

Waste Management Facility Design
The STS urination and defecation facility contains the following features, which have

proven successful:

a. Restraints - The following restraints are provided in the facility:

1. Spring loaded thigh bars that press the user against the opening used for defecation.

2. Footstraps to stabilize the body for clean up after defecation.

b. Urine collectors - Funnels at the end of a suction tube are used to collect urine only

(without defecation). For males, a straight conical funnel approximately 7.6 cm (3 in)

long and 5.4 cm (2-1/8 in) in diameter (at the large end) was selected as optimum. For

females, an oval funnel was developed which had angled air inlet openings to give a

vortex action to the airflow. Each crewmember has a personal collector.

c. Supplies - The compartment is arranged so that cleanup supplies can be readily

accessed. These supplies should include gloves, dry and wet wipes, tissues, germicidal

agents, etc. The overall layout is shown below.
Layout of the STS Waste Management Station

       In the past, during EVAs, urine was collected in male astronauts via a disposable

urethane-coated nylon bag. This UCD (urine collection device) was connected to their

bodies by velcro fasteners and a harness. For female astronauts a super-absorbent diaper,

MAG (Maximum Absorbent Garment) was worn. The MAG consists of five different

layers; the plastic outer liner, the coform absorbent material, the water absorbent layer,

the nonwoven layer, and the tricot liner. The plastic layer, as the outer most layer,

prevents excess liquid from leaving the garment. Immediately under this is the coform

absorbent layer. The coform absorbent layer is the layer that allows the MAG to conform

to the body for a secure fit and to allow some absorption.

       However, most of the absorption occurs in the gel layer. This layer consists of

tightly packed sodium polyacrylate crystals. These crystals have a distinct shape, due to

hydrogen bonding, that keeps them in a condensed shape. As water ( a protic substance

that contains hydrogen bonds) enters the crystals, the shape immediately changes. The

hydrogen bonds are broken, and the sodium atom leaves the acrylate group causing the
anionic oxygen to carry a negative charge. This causes the molecule to flatten out and

allows water groups to lie in between layers of crystals. Due to their high molecular

weight, the crystals do not completely dissolve in the water and instead form a gel layer

that will not be uncomfortable to the astronaut.

       Below this layer is a one way woven layer that allows the gel layer to slide over

the final tricot layer. Tricot is a soft layer of material that gently hugs the body giving a

stretch tight security, yet doesn‟t restrict movement while sleeping or any other activity.

This thermal wrap effectively traps warmth allowing the person to also stay warm.

Additionally, vaseline was once used to create a layer between the person and the MAG

to prevent diaper rash. Now, the UCD and the MAG are worn over the LCVG, reducing

the need for a vasoline layer. The UCD and MAG is shown below respectively.

-Find a method such that we can disinfect the waste and recycle it for usage as fertilizer.

This would work extremely well on a Mars colony or long term mission. This would aid

in self-sustaining habitats by fertilizing plants to be eaten. Another possibility is to send

the waste generated from urine through a disinfecting area (although urine should already

be sterile), cool it, use it for LCVG, pass it through PLSS to filter out the excess minerals

and then send it through for drinking water.
-The MAG, which is the present device, works quite well in terms of absorbency, but it is

limited by the ability to only take on liquids. Also, if anyone drinks a lot of fluids, the

person‟s MAG cannot support more than 32 fluid ounces so the urine would overflow.

This is a bigger problem for women in case of the need to urinate and possibly

menstruate in the same EVA. (A simple solution for the menstruating issue is to use

female hormones that prevent the woman from menstruating for several months. I think

they already do this)) The volume, which can be seen in FIG 3 contains enough fluid to

possibly cause overflow of the MAG, which could lead to some real discomfort. For

long duration space travel, this is not as practical as it may seem.

- One of the main issues concerning the fecal management system is the significant

amount of space that is required to store the used fecal bags. On many of the Apollo

missions, the volume provided by the waste stowage compartment was inadequate. Our

group feels that this problem can be resolved if the fecal matter is dehydrated and burned

instead of stored. Storage space is a valuable commodity on the shuttle and we feel that

designing a unit to eliminate the wastes will be advantageous in the long run. One section

of the unit would consist of water reclamation system that would completely dry out the

fecal matter and transfer the recovered water back into the purification unit. The second

part of the unit would consist of a „burning chamber‟ that would exist in a closed

atmosphere separate from the rest of the shuttle. The chamber would be composed of air

with approximately 20% oxygen (to simulate conditions on Earth). The fecal matter will

then enter this chamber and undergo a combustion reaction producing CO2 and water as

byproducts. The carbon dioxide would be absorbed by lithium hydroxide canisters, which
would eventually be disposed of. Our group feels that this unit will be very profitable

addition to the space shuttle because it will eliminate the need for a waste stowage


Conclusion: Although no official deadline for achieving human travel to Mars has been

set, scientists say that this mission is imminent. “Let's burn it into our brains that in our

lifetimes, we will extend the reach of these human species onto other planets and onto

other bodies in our solar system," said Daniel Golden, director of the U.S. National

Aeronautics and Space Administration (NASA). 1

       While many scientists say that a mission to Mars is technologically possible, there

are many questions as to whether it is practical, economic, or safe to undertake such a

mission. This interplanetary flight will take us 136 million to 150 million miles from

Earth, thus it will require astronauts to travel in space for at least a few years. This

extended length of space travel time that is required means that every element of the

shuttle and space suit should be functioning as efficiently as possible. The waste

management system is one of the most vital components of the space shuttle because the

astronauts must interact with it several times a day. Constructing a more efficient water

recovery and fecal disposal system is an extremely important consideration when

evaluating the space shuttle because a more resourceful, fine-tuned waste management

system will greatly extend the duration of time that astronauts can spend in space, which

will eventually enable us to travel to farther destinations.
Table 1

WASTE PRODUCTS        MASS (gm/person/day)      VOLUME


Hair growth           0.03 (0.3 to 0.5 mm per


Mensus (see note 1)   113.4                     113.4

Flatus as gas         -                         2000
WASTE PRODUCTS                  MASS (gm/person/day)   VOLUME


Solids in feces                 20                     19

Water in feces                  100                    100

Solid in urine                  70                     66

Water in urine (note 2)         1630                   1630


1. Approximately once every 26 to 34 days and lasts 4 to 6 days, approximately 80%

released during first 3 days.

2. Based on Skylab data

                                          APPENDIX A
Management Structure

-Jeff & Arul: Responsible for background research of the paper and organization of the


-Ray: Responsible for organization of the presentation.

-Liz: Responsible for editing paper


4/2- checked VLSB for waste removal info

4/4- went to engineering library to search for other methods to find information on

campus, called NASA AMES to check library. Got no response.

4/11- worked on putting pictures into the paper

4/14- met to work on the paper

Group Member Tasks

-Jeff – research EVA urine and defecation devices, look up history, help compile the

paper data, find pictures for history, presentation

-Arul – research water purification systems on the space shuttle, find out details about the

fecal bag, organize and found pictures for presentation.

-Ray –researched renal stone formations and urinary monitoring system as well as

helping out in the compilation of the final paper and organization of the paper

-Liz -Completed research on the MAG and current systems

Aided in editing of paper

(had some problems completing some work due to motorcycle accident)

Plan to Acquire Information

- interview someone in the field
- explore the NASA archives

- internet research

- search NASA AMES library


-Could not reach NASA AMES Library

-Difficult to find materials in campus libraries

-Difficult to find faculty with any background
Jeff Jong

Role summary

       In this 3rd project on waste removal, I found myself swamped by how much there

was to do on the project. I attempted to manage the group such that I organized times to

get everyone to meet. I was not assigned this, but I tried my best to make sure that

everyone was on track. This involved calling and e-mailing the other members to check

what they had done by the allotted time and having to find a meeting place to congregate.

I made sure that everyone had each other‟s contact information.

       Next, I researched information on the internet as well as worked with Arul in

trying to attain access to the Ames Research Center Library. I worked on finding

research on the LCVG, MAG, URA, UTS, at the Valley Life Sciences Building library

and at the Bechtel library, but they did not involve space relevant data. Compiling the

photos and data for the paper was completed by Arul and me. Part of the work was

proof-reading the paper, putting the pictures in the proper place, I worked on the power

point slides to approve what would be good points to exemplify, organized the logical

order of the presentation, found pictures and presented a portion of the presentation on

the EVA involved waste system.
Arul Krishnan

Role Summary

        For this project, I, Arul Krishnan, was responsible for researching the basic ideas

behind water reclamation and fecal management on the space shuttle. I did some general

research and decided what areas our group needed to focus its research on. With what I

found from my research, I also determined what aspects of waste management were the

most difficult to find.

        For the report, I wrote about the processes through which urine was recycled and

how fecal matter was stored. I also researched the specific things that could be improved

upon with these processes.

        During the presentation, I spoke several different parts of the urine receptacle

assembly and how the MAG functioned. I also explained some our group‟s ideas on how

the waste management system can function more efficiently. I also contributed some

graphs to our presentation, but we ended up using only one of them due to time

constraints. In addition to my part in the paper and the presentation, I was also present at

all of my groups‟ meetings and assisted in assigning everyone duties.
Liz Hulsey (one page summary)

-Completed research on the MAG and current systems

-Aided in editing of paper

-(had some problems completing some work due to motorcycle accident)
Ray Chung


       Since our topic covers a wide range of issues, we were all forced to do extensive

research and then meet up and decide which topics we would keep and delve into. I

researched issues ranging from renal stone formation and urinary monitoring systems, to

the effects of microgravity on the human body in terms of urination and defecation.

Although I did find significant information regarding renal stone formation and urinary

monitoring systems, we felt as a group that these topics did not relate to our overlying

theme of waste-management, and so we left them out of our paper. However, the said

topics are very relevant and if we had more time, I would love to do more research on

them. Nevertheless, our paper topic was finalized, which leads us to the presentation.

Once again my services were called to hand, and I gladly accepted.





Shared By: