A/V Geeks Lunch 12-22-2021

hello everybody i'm skip alzheimer and welcome to the av geeks lunchtime streaming show where we watch old 16 millimeter films and sometimes we watch an old 16 millimeter film about old 60 millimeter films um that last film was from the oregon archive uh how motion pictures talk and move of course the irony is uh it's a silent film so we don't actually get to hear uh the audio uh this was released by bellen howell um kind of a promotional film uh kind of an educational film um and i don't know if you noticed uh the image got a lot more kind of in and out of focus at the end and then it started kind of like bobbing around then there's that beautiful kind of montage scene of all the projectors and the cameras and stuff um so that film was way uh shrunk so basically it's succumbed to vinegar syndrome and it was curled and so we were running it through one of our scanners and basically we were adjusting the focus on the fly and also holding it kind of in place with our fingers so that it could run through and kind of trigger and yet still kind of maintain so it was i'm amazed we got what we got from that um and i would love to find a better copy of that at some point uh maybe one day we'll find it but um yeah uh that pretty much uh explains why film 16 millimeter film was um so important to classrooms one of them was it wasn't made out of nitrate uh too smaller portable um and you could inexpensively uh shoot and reproduce and distribute um lots of copies of it um so uh yeah i love showing films about films uh this next one is another uh one from the oregon archive that we scanned and this is an interesting one because it's uh i don't know what the final film was or what you know where it ended up if it ended up anywhere it's uh the title on the can was bicycle theft uh but this is obviously uh kind of raw outtakes and i think this was shot with sync sound with a camera called an oracon where you have a microphone it goes into this little box on the camera and it is actually riding the audio soundtrack as an optical soundtrack as you're shooting the film um traditionally it's a separate process where you have the film you have the projector or a projector you have the camera then you have a separate uh tape uh deck and you have the microphone and all that stuff and it's like usually in agra and you have some sort of sync and a clapper um that allows you to do more editing with sound and kind of have a separate thing while still maintaining a sync but the oricon is kind of on the fly so i feel like this was done with an aria-con it could have been a magnetic stripe but anyways here is bicycle theft enjoy okay ready this is officer brad goloth of the concord california police force a specialist in bicycle theft and chairman of the northern california bicycle officers association officer gallison the uh bike theft problem has grown tremendous proportions so that there are people in it who are specialists like yourself can you tell me a little bit about the size of the take well to show you the uh the rapid growth of the problem in 1970 we had in california about 92 000 bicycles stolen uh worth about five and a half million dollars yeah in 1971 the problem grew to such an extent that we had 500 000 bicycles stolen and this represented a value of about 30 million dollars so with 500 well it's no longer a juvenile problem is it no uh it's grown from that it's it's now more of a a regular crime just like auto theft or burglary or anything else a lot of people who are heavily involved in crime are turning to bicycle theft because of the availability of bicycles the fact that they can't be secured well and because they're high value i understand it's no longer a juvenile problem no it's gone beyond that now it's uh it's a widespread problem it's a the same type of crime to the criminal anymore as burglary or auto theft or any one of a number of crimes i think this is due to quite a few different factors one being the fact that the 10 speed has become very popular that's a valuable bicycle in it yes it is i think that the the average value of the 10 speed now is somewhere around 90 and many of them are up around 300 and 400. and these people you're beginning to see more and more professionals in the business that's right we're seeing people going around in ring stealing bicycle as opposed to uh situation okay i'm going to ask if they steal the order well this valuable merchandise is fairly easily stolen i understand yes it is most of the time because the people who own the merchant proper caravan what do they what do they do that's wrong well they they go out and they spend a hundred dollars for a bicycle and then they'll buy a dollar 29 lock to lock it up with and expect that to secure the bicycle against the bicycle thief it just doesn't work the bicycle thief cuts the chain with a bolt cutter or something like that right that's the usual tool used by the bicycle thief and most cheap blocks and cheap chains can be easily cut with a bolt cutter with no problem at all and i understand that combination locks are fairly easily opened by almost anybody combination locks have become a game with kids nowadays and i most uh most kids by the time they're in seventh or eighth grade can open just about any combination locked around i see okay well cheap locks and chains won't do it and uh i guess there's some other mistakes a lot of us making trying to take care of our bicycles yes a lot of people when they lock their bike up we'll lock it someplace where it can't be seen by other people and that's a mistake they try to hide it down an alley or something well it's a good idea and chances are you might hide it from a bicycle thief or two but you're also going to hide it from the view of everyone else and if a thief does find it he's got forever and a day to work on it so maybe there's safety in in numbers or a crowd right also a lot of people will park their bicycle in the dark somewhere or anywhere where it's easy for a thief to work on without being noticed is a mistake even in a garage with an open front garage door not safe in a garage either huh no not unless your garage is is closed and locked uh is locking a bike with a good chain let's say through the wheel a good idea no not just through one wheel to be locked properly a bicycle should be locked with a chain through both wheels and through the frame and around some solid object like a carport post or a porch pole or a telephone pole so the good chain and a good lock right okay where do you consider the safest place to leave a bike if you're out on the street and you have to leave it temporarily well i would say the safest place would naturally be where there's a the most people around the entrance to a shopping mall right in front of a busy department store but locked to something solid as i said a telephone pole or something like that if it's at night not only uh where there's a lot of people around but you should leave it under a light somewhere a bright light where it can be easily seen pretty much the same way you'd handle a good car right whoop kill it am i getting a bud okay okay well brad a while ago we were talking about safety of placing your bike properly and protecting it locking it up and we've got to mention too much about garages would you tell us again about how to keep your bike from being stolen well first of all it's important to keep your bicycle when it's locked someplace to keep it in as full of public view as you can unless it's in the interior of your home in your bedroom or something like that you want to put it where there's a great many people walking in the area if it's at night you want to keep it in a light some place like under a street light or under the front of a store where there's bright lights a lot of people make the mistake of putting the bicycle in their garage at night and this is a mistake especially if you leave your front garage door open because what better place for a bike thief to work than in a darkened garage where he can see everybody going by but nobody going by can see him he's got all the time in the world okay thanks ready brad i understand a lot of people think their bikes are safe in uh garages and you know on their property in the front yards is that true no i would say for the most part it's not true the only place your bicycle's really safe is in your house or in a locked garage just leaving it in the garage i think that uh we'd find uh from a survey that probably 30 to 40 percent of our thefts occur from front yards and from open garages an open garage especially at night is a beautiful place for a thief to work without fear of apprehension in most cases steve i understand that the california officers are advocating some measures to help solve this problem what are they well we're asking that the state set up a statewide registration file and a statewide computerized stolen file or hot file with all the pertinent information included in it and this would be would be based on the manufacturer's serial numbers on the bikes however until that time until such a system set up we're asking the people go to their local police departments or local sheriff's offices and have their bicycles registered and licensed and most departments here in california are stamping a number in this portion of the bicycle which indicates the city in which it was stamped and the serial number that we give the bicycle and are applying a license tag in this area just underneath the seat to indicate that it's been licensed then a full description of the bicycle's on file okay we've been talking about a lot of ways to prevent bicycle theft but all in all i think that the best is a safe secure locking device for the bicycle an example of a safe secure locking device is a lock such as this which is case harden we've been talking about a lot of ways to prevent bicycle theft but all in all the best method to prevent bicycle theft in the first place before it occurs and to safeguard your bicycle is to find a secure locking device that will protect your bicycle against the ordinary thief an example of one of these devices is a lock such as i am holding here which is a case hardened lock both the shackle and the body of the lock are case hardened and it's operated by a key and not a combination there are a variety of such locks to lock the bicycle securely and to lock it properly you have to pass the chain through both wheels the front and the back wheel and through the frame and lock it to some solid object such as a carport pole or a porch post or even a telephone pole something that can't be moved and the bicycle can't be taken away from what's the best way to take care bicycle in summary i think the the best thing that you can do is number one to get your bicycle registered and licensed that way you run a lot less chance having it stolen and you've got a description on file with the police number two buy the strongest case hardened key lock and the strongest case hardened chain that you can find and number three learn to lock your bike properly and do it in such a place that the thief doesn't have a good chance to work on your bicycle thank you good now wait a second put the scrim on it's off okay brad in summary in some in summary the best way to protect your bicycle is to do three things first of all get your bicycle licensed and registered that way it's got a lot less chance of being stolen and there's a description of your bicycle on file with the police number two obtain the best strongest case hardened key lock and case hardened chain that you can find and number three learn how to lock your bike properly and use a little common sense and where you put your bike and don't let the thief have a chance to work on your bicycle i love that footage of the end of the uh snipping the the chain um yeah i'm not sure the the provenance of this i don't know exactly where this came from i mean obviously he's talking about california um so i don't know how this ended up in pittsburgh with the oregon archive but that's the way film is sometimes film floats around um and ends up places it's not supposed to be i think some of the most recent uh discoveries as far as of finding lost films have been finding them in places that they weren't supposed to be like barns or uh in a filled-in swimming pool in uh northern canada uh or uh buildings or in archives that they're just not supposed to be in um that's kind of an interesting thing to see um i think it's time to learn some facts about backs [Music] push pull twist turn lift and carry actions that we take for granted as we perform these everyday tasks our conscious mind is busy with other more important thoughts we have learned to trust our body and most of the time it does a very good job yet more man-hours are lost due to spring sprains and back trouble than to the common cold [Music] last year 28 million americans went to the doctor to complain about their aching backs let's take harry here for example harry could be anyone working anywhere one morning something goes wrong with his back diagnosis muscle sprain prescription additional rest hot packs and aspirin take it easy why for the first time in his life that afternoon harry learned about his back almost all of the body's vital parts are supported by the spine a vertical stack of 26 separate bones that form a flexible column but the back is much more than a stack of bones with a simple command from your brain the spine can be held rigid during the most violent movements or it can be made almost as flexible as a whip for flexibility the bones are separated by discs like a golf ball a disc has a tough outer shell and a soft center each disc can be compressed in any direction allowing the spinal tower to bend quite far forward and sideways for rigidity it depends upon ligaments which run its full length front and back on a series of short muscles which are attached to knobs on the vertebrae and the complex fabric of long back muscles our back is well designed but things do go wrong some people are born with structural flaws occasionally a very serious disease can the back an unnecessary burden is placed on the back by an overweight condition or poor posture back pain can also be caused by problems which have nothing directly to do with the back like a cold or flu an ulcer or a kidney ailment but most of the time our back problems can be traced to a lack of muscle tone this tone not only keeps the muscles ready for use but holds the bones in place without it your framework is more susceptible to damage loss of muscle tone occurs slowly over a period of months or years without your being aware of it the sedentary lives which many of us live do not allow the body its necessary muscular activity many so-called normal backs have slight imperfections these are flaws you are born with as a person gets older and starts losing muscle tone these faults can show up and cause trouble let's look at some of the things that many of us have been doing over the last few months we've spent most of our time sitting down [Music] our posture tends to get worse over the years daily stress intentions both at work and at home keep us from fully relaxing [Music] when we find a few spare moments on busy weekends we may try to unwind a bit [Music] and occasionally there's a lot to be done and not much time to do it [Music] sometimes a part of your body can be pushed beyond its limits just as metal will tear and break under repeated mechanical stress so it's impossible to say exactly what happened to harry it was the sum total of many small abuses which finally caught up with him man's upright stance is a comparatively new evolutionary development and he is still imperfectly balanced his spine lies mostly behind the gravity line thus he tends to lean forward this tendency must be constantly checked by the muscles of the back and neck putting a strain on them poor posture and an overweight condition compound the problem in a normal upright position your muscle tone manages this job pretty well but by bending forward you add the weight of your head and upper body to the burden this is true whether you are standing or sitting at a desk all day with afternoon fatigue you tend to slump forward the farther you slump the more off balance you become the more your muscles have to work the remedy sit up straight lean back and rest occasionally jobs that require continuous cramped twisted or unusual positions can also give the back trouble muscles that are weak from lack of use can be over taxed resulting in strain pain and cramps awkward positions can also threaten the joints and ligaments don't overreach when trimming trees the remedy straighten the back and rest occasionally back injuries are not caused by unsafe working conditions but by unsafe working habits back injury can result from trying to move something too heavy or too fast or by suddenly forcing your body into a position of great strain which brings us to the subject of improper lifting a very common source of back trouble your body will instinctively do things the easy way and it's often easier to bend over like this to pick something up every joint and muscle should have a little bit of yield freedom to absorb stress and shock when your body straightens up it has to bring with it another load in addition to the weight of your head and upper body a load can be five times heavier for your back if lifted improperly lifting heavy loads is not a natural thing it's a skill no matter how much lifting you've done in the past someday you may drop your guard and end up with trouble there are very definite rules designed to take the danger out of lifting never lift anything you have any doubts about only lift loads that you can handle easily and comfortably your past experience should guide you study the object to be lifted its size shape and weight look for splinters or sharp protrusions gloves may be needed consider the height it may have to be lifted how far it must be carried on smooth ground or rough upstairs or on a level [Music] make sure it is well lit [Music] check the floor for debris [Music] for slippery conditions and for possible obstructions expect the route to be traveled prop doors and gates open always face the object to be lifted place your feet close to the base of the object make sure your footing is firm and solid squat close to the load keep your back as straight as possible the body is naturally formed to be upright and is strongest in this position get a firm grip on the object and test the load making sure you can lift it now holding the load firmly and close to your body gradually push up with your legs these are your strongest muscles let them do most of the work if the load is too heavy or awkward there are several things you can do [Music] get someone to help you in a team effort one man should direct the move split the load making two or more trips [Music] tip it end for end [Music] drag it roll it get a hand truck [Music] jog it along on the corners [Music] never carry loads that prevent you from seeing where you're going avoid walking backwards [Music] if it's necessary to change your direction when carrying something heavy be careful not to twist your body because your muscles must suddenly deal with your entire weight if you're carrying a heavy object this problem is compounded if you must change directions turn yourself by changes of foot position when placing a load on a bench table or shelf first set it on the edge and then push it forward with your arms and legs in putting a load down use the reverse procedure of lifting and don't forget there's another problem which applies whether you lift or not [Music] exercise most people know that regular exercise helps keep muscle tone it also strengthens muscles [Music] but the same exercise that keeps one person fit may aggravate another exercise should be prescribed by a physician and should be within the tolerance of the individual doctors agree that there's one kind of exercise that is bad for everybody irregular exercise like 18 holes of golf after being away from the game for a while or push-up contests twice a year or five sets of tennis every three weeks if you're going to exercise like this you must do it regularly otherwise aches pains or even collapse may result harry was lucky he ended up with only a sprain it could easily have been a lot worse he could have ended up in the hospital but what's more important it needn't have happened in the first place harry could have been someone working somewhere with a very clear knowledge of certain facts about his back [Music] [Music] so [Music] [Applause] [Music] i'm guessing that this film was made because of that was a common factor is people suffering from back problems working at the bell system either sitting at their desks all the time or those periodic push-up contests that they you know the semi-annual twice a year they had a push-up contest and they decided you know a lot a lot of people are getting hurt from that also uh debris as opposed to debris debris i don't know do some people pronounce it that way um not sure um so uh yeah it's always interesting to see when you have a film that's made by another company that's totally addressing something different it's like the um bell companies they did a film about um gas mileage and about um how to save money with gas during the energy crisis i was like why did they do that um and you know it could have been for their workers it could also have been uh something that they showed and said like you know is this trip really necessary maybe you should just call somebody it's a lot quicker that way um all right so we uh we've learned a lot today how motion pictures talk and move we've learned how um to steal a bike back in the 70s uh in contra costa county um we learned about uh backs and um this one's about concrete from mountains to microns enjoy [Music] this is the story of portland cement the most useful and most widely used of all the world's building materials oddly enough unless you watch a construction job closely or are a do-it-yourself builder around the house you rarely see portland cement by itself but concrete of which cement is the essential ingredient has so many different and important uses in such a variety of shapes and sizes that this fine powdery material is part of your life and is working for you every day for example you may live in an attractive house built of concrete block or a tall apartment building when you travel from one place to another you ride over miles of concrete highways under dozens of concrete overpasses and sometimes over high bridges spanning gorges between mountains [Music] at night you stay either at a multi-story hotel or in one of the hundreds of motels along the route either of which may be built of concrete wherever you look you see fire-safe concrete protecting children in schools patients in great hospitals and worshipers in chapels churches and synagogues concrete houses industry banks and offices stores and shopping centers underneath our cities thousands of miles of concrete pipeline carry domestic and industrial wastes dangerous racing rivers are harnessed by locks and dams converting them into deep waterways for ocean-going ships huge concrete tetrapods weighing up to 31 tons each locked together to protect eroding shorelines from waves of great height and violence great dams protect thousands of square miles from floods the stored water is used in making electricity for home and industry or provides a steady source of precious water for irrigation irrigation facilities feeding floors silos and buildings of concrete have cut farm losses and reduced the drudgery of farm labor a thin slab of concrete takes you from your home to the corner store the biggest jets take off or land on long heavy-duty concrete runways and now when you shake off the earth and head for outer space you blast off from a massive concrete launching pad what is this concrete that has so many forms and uses and why do so many people everywhere use it in the first place it is made of a few simple inexpensive materials gravel or crushed rock sand and water all of which you recognize as the most abundant materials on the face of the earth and portland cement a manufactured product made of the commonest elements found in the earth's crust when these materials are properly proportioned and mixed they form an easily workable mass which can be molded into any shape or form useful in construction when concrete cures it forms a mass harder and more durable than any of the materials that went into it it took a million pounds of pressure developed by this huge compression machine to break this concrete cylinder and you will notice that the brakes occurred right through the rocks and not around them what happens when concrete cures and becomes so hard nothing much has happened to the stone and the sand except that they are rather evenly distributed but where is the water in the cement some of the water is evaporated but lots of it has combined with the cement to form a new substance called cement water paste which entirely surrounds every stone and every grain of sand and binds them together so portland cement is the essential ingredient of concrete it is the only difference between water packed dry soil and solid concrete the most noticeable characteristic of portland cement is that it's a very fine fluffy powder it may be various shades of gray and for special uses such as making paints and color products it may be pure white but the notable characteristic is still its fineness i can truthfully say that cement is finer than the most expensive face powder and that several thousand particles of cement would not be overcrowded on the head of a pin but the fact is no one ever saw a particle of cement until the electron microscope came along to make it possible to magnify microns up to visibility for a particle of portland cement is measured in microns one twenty five thousandth of an inch and this spoof contains millions of them [Music] this fineness is important because in concrete the cement water paste must entirely surround every stone and every grain of sand in order to bind together the mass of granular materials and obtaining this fineness is one of the major processes in making portland cement the two principal elements combined in portland cement are calcium and silica these are obtained from raw materials limestone beds of marl shale clay chalk and old oyster beds all of which must be extracted from thick deposits in mountains hills ledges underground mines or from the bottom of the ocean it takes 3200 pounds of these raw materials to make a single ton of cement so the manufacturer of portland cement is literally a job of reducing mountains to micron sized particles making portland cement is a precise chemical process which follows four basic steps gathering the raw materials crushing and grinding them to powder burning them and then grinding the burn materials to a super fine powder this process is employed the world over for portland cement is not a brand name but a type of cement it was given that name by its inventor joseph in 1824 because he thought that the concrete made from his new cement resembled a natural building stone quarried on the isle of portland off the coast of england most cement plants are located near their supply of raw materials which may be open-faced quarries deep mines [Music] beds of clay or marl or old shell deposits some mills purchase rock from more distant quarries or shell from commercial dredgers these are brought to the plant by rail and by barge [Music] most frequent sources of raw materials are open-faced quarries thick deposits of limestone and shale that have lain in the earth for millions of years these materials must be loosened from their ledges by boring vertical shafts from the top and charging them with explosive each multiple blast drops thousands of tons of rock onto the quarry floor in sizes suitable for transporting to the raw material storage areas large heavy-duty trucks loaded by great shovels are commonly used to move loose rock to the plant fleets of these trucks operate continuously until the quarry floor is cleared for the next blast rock from the quarry is usually dumped directly into primary crushers which reduce the material to sizes suitable for storage and handling primary crushers smash boulders the size of pianos into pieces the size of baseballs these are then fit into a secondary crusher which reduces all raw materials to a size not exceeding three-fourths of an inch the crushed rock is now moved into a large storage area where each kind of raw material to be used in making cement is stored separately a plant usually keeps from several days to several weeks supply on hand to assure continuous operation plant chemists continuously analyze each of the raw materials entering the mill thus whatever the materials may be they know the proper proportion of limestone shell moral shale slag or silica sand that must be combined to enter the next critical step in manufacture which is raw grinding or preparation of the materials for burning there are two methods of preparing the raw materials for burning one is called the dry process the other the wet process some cement mills use one process on the other but the purpose of both is the same to grind the materials to a fine powder and to blend the various kinds of materials to be used so that they're thoroughly mixed a properly proportioned mixture is essential to affect the desired chemical changes in the kiln in the dry process raw materials are taken from storage loaded into hoppers in previously determined proportions and charged into a rotating ball mill in this mill hundreds of steel balls carried up the side of the cylinder fall back into the constantly turning raw materials this action accomplishes preliminary grinding the material then passes into other rotating mills called tube mills where thousands of smaller steel balls grind the material to the finest required for the burning process in many plants ball and tube mills are combined in so-called compartment mills the fine ground raw materials from which samples have been taken for testing are now pumped or carried by conveyors to a battery of huge storage silos here supplies sufficient for several days of mill operation are always kept on hand in the wet process raw materials are charged into a ball mill but now water is added in the ratio of 35 water to 65 dry materials to form a creamy mixture called slurry the slurry passes through tube or compartment mills for fine grinding and is then pumped into a series of mixing tanks here samples are taken for laboratory analysis agitators thoroughly mix the slurry aided by air blown in from the bottom of the tank now predetermined amounts of slurry from various mixing tanks are pumped into blending tanks the color-coded pipelines indicate the number of different slurry mixes that may need to be combined to produce the desired chemical combination the blended slurry is then pumped into large storage tanks to await burning the third and most spectacular process in making cement from this point on the wet and dry processes are identical the dry powder or the slurry has been carefully analyzed in the plant laboratory and the materials are ready to be fed into the kiln made of steel and lined with fire brick to withstand the intense heat the rotary kiln is the largest piece of moving machinery used in any industry some kilns are over 500 feet long longer than a 40 story building is high the kiln slopes downward from the feed intake toward the end where the hot product is discharged dropping about half an inch for every foot of its length it rotates about once a minute thus exposing all of the raw materials evenly to flames that reach temperatures of 2700 degrees every few minutes enough coal oil or natural gas is consumed in each kiln to heat an average home for several days operation of the kiln is carefully controlled through every minute of its 24 hour per day operation a panel of 20 or more instruments indicate temperature at various areas in the kiln speed of kiln rotation rate of fuel consumption draft production rate and other vital information the operator may also visually check the progress of materials through the kiln by means of a specially constructed port near the hot end during heating the materials pass through a spectacular range of color changes from glowing violet to red to white hot incandescence here's where the chemical transformation of raw materials into new useful compounds takes place during the four hours required to pass through the kiln the calcium silicates aluminates and other compounds are formed that give portland cement its binding ability and strength when the heated material emerges from the end of the kiln it appears in the form of red hot marble-sized glass hard balls called clinker the next step is to cool the clinker by passing it through one of several types of cooling devices heat given off by cooling the clinker is returned to the kiln to save fuel and improve burning efficiency outside the kilns at the stacks additional complex equipment plays a silent but important role here giant electrostatic precipitators remove dust and fumes from the waste heat releasing cleaned exhaust heat into the air around the plant [Music] when cooled the clinker may be removed to storage shipped to another plant for grinding or passed directly into the fourth and final stage of cement making fine grinding the final stage in the manufacture of portland cement is the fine grinding that reduces the clinker to a powder made up of particles the size of microns this process employs some of the same massive moving equipment that has been used in previous processing steps before final grinding a small quantity of gypsum is added to the clinker this aids in regulating the setting time when the cement is used in making concrete now the clinker is charged into rotating ball and tube mills where thousands of steel balls grind the material to the super fine powder that is portland cement in some mills the ground material is passed through separators in which air is used to carry away the fine material returning coarser particles for additional grinding the cement is now so fine that it will pass easily through a sieve with forty thousand openings per square inch throughout the final process the freshly ground cement is tested every 60 minutes to assure a product that will make concrete of uniform strength and durability when mixed according to applicable specifications from the grinding mills the cement is pumped into batteries of tall silos where it is stored awaiting shipment at the base of each silo is a track on which a mobile cement pump can be moved from silo to silo giving the manufacturer easy access to all the cement in storage this pump sends the cement to the packing and loading area where it is prepared for shipment by various means of transportation much cement is put into bags for shipping this is done by semi-automatic machines which fill and seal a 94-pound bag of cement in three seconds each bag of cement is one cubic foot a convenient measure later on when properly mixing cement sand gravel and water to make concrete [Music] the heavy paper bags have self-sealing valves which are closed by the weight of the cement as the bag drops away from the machine large quantities of cement are shipped by railroad much of it in bulk in a specially designed hopper bottom cars this car loader can fill a cement car in a few minutes any dust resulting is removed by a special device and returned to the storage silo increasing amounts of bulk cement are now being shipped directly to job sites by transport trucks these are loaded at the storage silos by overhead equipment similar to that used in rail car loading where plants are located near waterways large quantities of cement are transported by ship or barge every day all over the united states and canada more than 175 mills and plants carry on these processes of blasting crushing burning grinding and shipping portland cement although these mills vary in size from one kiln to a dozen or more and use different raw materials their methods are nearly identical therefore the finished product portland cement is of a consistently high quality no matter where it is made this is because cement is made to meet rigid specifications which are recognized and carefully followed by all manufacturers of portland cement more than 90 percent of these cement mills are members of the portland cement association established in 1916 as an unincorporated non-profit organization joined and voluntarily supported by its members its purpose is to improve both the quality of portland cement and its use in concrete and other cement using products among the many important activities of the association is the planning and directing of a cement plant safety program that has over the years made the cement industry the safest of all heavy industries scores of plants have outstanding long time safety records and every mill is proud of its continuing record of accident-free days the portland cement association operates the largest and most modern research and development laboratories devoted to cement and concrete [Music] its staff of trained research engineers and scientists carry on a never-ending program of basic and applied research within these specially built and equipped laboratories and supervise such far-flung field projects as this long-time study of the effects of time and weather on the durability of thousands of different concrete specimens a continuous study of the effects of salt water and tide action on concrete piles and piers and this caravan which carries a fully equipped laboratory to the job or the project to conduct field tests the association's general office in chicago is a clearinghouse for the latest technical information concerned with portland cement and concrete here a large staff provides engineering and educational services highly trained engineers writers and artists and photographers translate technical information into bulletins manuals publications and films for public use and finally the association maintains six regional offices and 33 widely scattered district offices manned by more than 400 specially trained engineers who work with architects engineers and contractors on problems involving the use of concrete and cement in construction this combined activity in research engineering and educational services and technical assistance in the field has not only assured better and safer highways more beautiful and economical buildings and more durable bridges and dams but has encouraged the design and construction of the many new and exciting shapes and forms in architectural and engineering structures that are fast changing the face of america all this has been made possible by the process that tears down mountains [Music] and turns them into the fine micron size particles of the most useful of all building materials portland cement [Music] i love that film um and i'm happy that some of you loved it it's it's this uh very niche like you know how something's made and they just go in and we learned all these technical terms we sold all this really amazing stuff that you know you just don't see it's like oh that's a cement factory yeah they just you just assume they mix this and they mix this it's like no there's this whole process it's like coffee it's like the crazy process to make coffee or chocolate is is insane considering how inexpensive it is um but speaking of coffee if you'd like to support us one way you can support us for showing these fascinating films this sounds like a pbs thing you know we we're happy to bring you this stuff but it costs us money so to support us you can buy us coffee by uh going to ko dash fi.com av geeks um you can also go to avgeeks.com and see other things we have online and there's dvds you can buy there as well also just hit the thumbs up or the like or the you know the whatever button um those are great ways to uh tell the internet that um it still should support us in some way um anyways we'll be back again tomorrow one o'clock as always it's great to see you and we will see you again soon everybody take care