Document 6RxN3ok29kw8rxQwL6a6mgXR9

1 I A, ylI Art work courtesy ot industrial Noise Control, Inc. L IA 26806 efs review the bidding. For son* time LEAD MAGAZINE has tured articles on the application of lead in noise control. This issue is no excep. tion. Why? It's something like Willie Sutton's response to the question why he robbed banks: '`That's where the moner is.'' Editorially: that's where reader interest is. Take LIA's ad campaign on noise control for example. These ads appear ig PLANT ENGINEERING, MACHINE DESIGN and SOUND & VIBRATION. The pertinent thing to observe here is that these ads typically draw hundreds of inquiries or about five to ten times the average of other advertisements in these publications. This high level of interest is displayed by original equipment manufacturers who must supply machines and tools to meet increasingly stringent noise specs. Plant managers and industrial hygienists too are looking for answers to in-plant noise. Lead is a feasible answer. However, there are many questions of product acceptance, problem and analy sis, and installation techniques to he thrashed out. With the objective of effet*ing better information transfer among all concerned, LIA is planning its W symposium on noise control in 1911 Details on this event will be sent to later. In the meanwhile, read the featm* article on pages 12-13. Printing press* pipe forming machines and engine roots* are cited as noise makers. And lead * there, knocking the dBs out of them- r European-inspired automotive design is reflected in this prototype Globe-Union electric passenger car, the most advanced of its type yet produced in this country. Exciting new electric vehicles on the horizon There have been significant advances in developing improved, mainte Special 12-volt lead-acid batteries used to power the car reportedly provide nance-free batteries for use in electric higher efficiency per unit weight or vehicles. However, body and interior volume than conventional units. The designs by electric vehicle producers batteries incorporate a polypropylene have lagged. heat-sealed container and cover, com It appears that's changing. Thanks to puter-aided grid designs, specially increased use of professional automo formulated high porosity active plate tive designers, more attention is being material, microporous polyethylene paid to the sales appeal of both the ex separators, safety vents with built-in terior and interior of electric vehicles. flame arrestors; larger and increased For example, one of the most dra number of plates for improved electrical matically styled battery-powered cars performance at high current draws. produced anywhere in the world was in Preliminary performance testing of troduced during the International Elec Endura during a harsh Milwaukee win tric Vehicle Exposition earlier this year ter produced remarkably good results. in Chicago. Incorporating all the latest With a full charge, Endura was driven lead-acid battery technological innova on suburban streets at city speeds of tions, the car was developed by Globe- AO-35 miles per hour for over 100 miles. Lnion. The car was designed by McKee The car also has reached speeds in ex Engineering, the company that designed cess of 60 miles per hour under express ESB's well known Sundancer, a proto way conditions. type two-seater electric passenger car whose streamlined design is as modern Sears now into electric cars now as it was when the vehicle was in Meanwhile, another prototype electric troduced about six years ago. passenger car has been introduced from The Globe-Union vehicle, named En- an unexpected source. Sears. Designed to dura, is powered by twenty 12-volt lead showcase the company's specially devel batteries. The most striking thing about oped lead batteries for electric vehicles, the car is its appearance. It features an the car is based on an existing passenger aerodynamic designed fiberglass body car design for the Fiat 128-3P. The ex that looks as though it's a product of a terior of the car has been redesigned leading Italian automotive body stylist. for more streamlining to present By replacing the car's removable hatch minimal frontal area and low back, the car can function as a 2 -j- 2 wind resistance. The car coupe or a station wagon. features an aluminum Another unique feature of the car is its elegant interior and monopanel electronic control board. One merely touches the desired control area on the panel to activate the ignition, lights and 'ipers. The system, which also activates be monitoring accessories, was devel oped by the company's Centralab Elec tronics Division. front end cap with integral bumper, quad rectangular headlights with trans parent covers, and a redesigned interior to provide a good passenger package for two,with adequate comfort and leg room. Named the XDH-1, the car has ex ceeded 75 mph, and it will easily cruise at 65 mph according to Sears. The car has no trouble maintaining the legal 55-mph speed limit, with reserve speed for passing or emergency situations. Twenty batteries are required for the desired range of the car. They are mounted in the car in 10 packs each located in the area formerly occupied by the rear seat and extending partiallv into the luggage compartment. Five bat teries are located under the hood. A marine type battery provides power to operate accessories. While both cars are prototypes, their acceptance by the general public is likely to influence the design of pas senger cars reported to be in pre-produc tion study by major Detroit companies. American Motors, whose wholly-owned subsidiary AM General has produced 350 electric Jeep-type vehicles for the U.S. Postal Service, recently released sketches of a streamlined electric threepassenger commuter car. A European division of Chrysler is known to be ac tive in electric vehicle development. And, perhaps most significant of all. Gen eral Motors has apparently decided to enter the electric vehicle market in the immediate future. Elliott M. Estes, pres ident of GM, told the Econonatftflub of New York that one kind of=Efe tech nology GM "is excited about ... is the progress we've made toward building an electric car that is suitable for use as a shopper or commuter vehicle in two- or three-car families." example of the Interest In the electric vehicle market being displayed by non-eutomotlve companies la this modified version ot a standard Fiat passenger car, developed by Sears Roebuck & Co. L IA 2680 7 Aerospace house features solar-powered battery energy Portable power for remote locations What's the nation's space agency-- the National Aeronautics and power failures, a fire detection system, a security system and a driveway spot Space Administration (NASA)--doinglight. building a house here on earth? The multimode electronic lighting When NASA was assigned the job of "satellight" used for the lead battery- guiding the nation's multi-billion dollar powered emergency lighting system fea aerospace program, it was also given an tures the high efficiency and long life of additional task that few Americans know tluorescent lamps. The extremely high about: transfer the vast amount of aero light output results in low-cost electricity space technology to U.S.'industry so that drain. the general public--the taxpayers who Other energy-saving devices include Students at the Southern Calif0 Institute of Architecture in jrnia Monica have solved a problem of p"'a viding electrical power for remote loc" tions such as construction and tern rary maintenance sites and forest -potting stations. They have develops a portable wind generator that chart.,, a 12-volt DC lead storage battery, ' \ la m \V P1 th Ih in al paid the bill for the aerospace program 432 sq. ft. of fluid-plate, fluid-type solar A surplus Air Force missile trails --would beneht. For example, NASA has erected a "technology utilization house" at its Langley Research Center in Hampton, Va., to show how technological spinoSs from the aerospace program can be used collectors. Used in combination with nighttime radiators and a heat pump, the collectors supply virtually all re quirements for space heating and do mestic hot water. A waste water recy cling system similar to those developed was adapted to transport the generator This enables the device to be mov^ from site to site to take advantage ,,i ideal wind generating conditions. On site, screwjacks on each corner ry the 1-ft. by o-ft. trailer stabilize the p|a, U> tli tli L'i \* profitably by the construction industry. The house was designed with compo nents and materials that are currently available or will be on the market within five years. The house has many energy-saving features. Their incorporation in a house would result in an estimated 320,000 in savings over a 20-year period. One of the most interesting energysaving devices used in the house is a solar collector system that generates electricity directly from the sun's energy. Originally developed by N ASA to power space satellites, the devices are called silicon solar cells. Simply stated, their use permits the conversion of energy from sunlight into electrical energy without moving parts. Energy supplied by the silicon solar cells is stored in one of the most eco nomical, readily available devices sold today--a 12-volt lead acid battery simi lar to starting, lighting and ignition tSLI) batteries used in automobiles. Energy stored in the batteries is used to power emergency indoor lighting during for manned space satellites and inter planetary travel, light bulbs that incor porate a temperature-compensating thermister to protect them from current surges that decrease bulb life, and spe cial insulation are also included. The technology utilization house is of contemporary, one-story design. It features a large living room with fire place, dining area, kitchen, two baths, laundry, two-car garage and outdoor living area. Total enclosed living space will be approximately 1,500 sq. ft. Langley researchers determined that a contemporary house, occupied by a family of four, uses the equivalent of about 46,000 kilowatt hours of energy a year for central heating and air .onditioning, water heating, lights, kitchen appliances, television, furnace fan and other equipment. The NASA Tech House will use only about 15,000 kilowatt hours of energy a year. This two-thirds saving.will not only conserve valuable eneTgy re sources, but will pay for the initial in vestment in a relatively short time. form for the hydraulically-hoisted tower The tower mechanism was converter] from a surplus hvdraulic lift. The ment lifts the wind generator to a ma\i. mum height of 15-ft. (as shown i. Gm wires from the base of the generator t, the gruund keep it upright in a \ nriete of wind conditions. At the top of the hydraulic-lift lower are three 8-ft. long stainless steel .-hafts, and a main outer shaft. The tower as sembly pivots on an arm constructed from leftover missile carrier parts orizinally installed on the trailer. The hand fabricated blades automati cally feather when wind speed in creases so much the generator can not operate safely. The main shaft turns a set of gears which boost alter nator speed. The alternator, with a maximum of 75 amps, is activated lu re m to m wi hi of de re Lyr pr O en by a centrifugally operated micro switch at 1000 rpm. It is estimated that the wind gen erator can pro vide a significant amount of energy for a small, energy conserving house- Lriold. g Energy generated by photovoltaic solar ceils mounted on root of garage (circla) is stored in lead batteries to provide alternate electricity for specieI solar power demonstration house built by NASA at Hampton, Va. 4 OQ 4 Ancient recycled lead used to restore centuries-old stained glass windows isitors to the ancient Canterbury Cathedral at Canterbury, Kent, Eng land. are impressed bv the church's [nagnificent old leaded stained glass lviiidous. But most of those making the pilgrimage to Canterbury are unaware lhat the windows are in the process of ijeina restored using much of the orig inal lead which joined the stained glass almost eight centuries ago. The cathedral's windows represent the oldest and largest collection of leaded uained glass in England. The "Genea logical" sequence of windows, tracing die human ancestry of Christ, and the three "middle windows'' portraying in cidents from Christ's life and passion, Jate back to 1178. The "Theological" windows, which tell Bible stories in pic tures. were also completed in the 12th centurv. There also are many fine win dow? dating (mm the loth. I Ith and !5th centuries. Very few cathedrals in the world can match this beautiful, yaried and his torically important collection. Unfor tunately. many of the windows have not withstood the ravages of time and the highly corrosive atmospheric conditions of modern times. In some cases the severity of the damage threatens to destroy the ancient windows. For this reason, an extensive restoration pro gram w as launched in 1973 to halt this progressive deterioration. Original lead stands test of time Interestingly enough, restoration op erations have revealed that much of the lead that was originally used to frame the stained glass panels remains in good condition today. According to Frederick Cole. Director of Canterbury's Stained Glass Restoration Program, the lead used in the 12th and 13th century work has held up exceptionally well. Some ex perts consider this lead to be superior to the alloyed lead used in the 14th and loth centuries. Although the condition of the original lead demonstrates its characteristic dur ability. Cole cited one instance where environmental conditions had taken their toll. "When I examined the windows in the Cathedral's library," he related, "I was surprised to find the lead was de composing. In doing so it had formed a grey slime on the inner surface of the windows. A subsequent investigation by the Lead Development Association re vealed that the trouble w'as caused by the mingling of acid released from some new oak book shelves and the sulphur dioxide in the atmosphere. We over came this with added ventilation." Unlike the quality of the lead used in the ancient windows, the chemical com position of the glass itself made it un stable and less resistant to corrosion than modern glass. Most of the 12th and 13th century glass is heavily corroded. This takes the form of pitting on the exterior surface. In some cases the pit ting has eaten all the way through the glass. The corrosion process is thought to have been accelerated by the in creased accumulation of chemicals in the atmosphere since the advent of the Industrial Revolution. Lead recycled for new joining A modern studio was set up on the Canterbury grounds to carry out the restorative program, which will take an estimated 20 years. When the windows are removed and taken apart the an cient lead is recycled, including the 60-40 tin lead solder used for joining. The unframed glass is thoroughly cleaned through the use of chemical solutions or ultrasonic baths. In addi tion, any broken glass is repaired. The panels are then reassembled and joined with the recycled lead. The glass is then reinstalled and a second clear glasff is installed outside the original window to protect it from reweathering. This external window is lightly leaded in general conformation to the leading on the inside windows. To date, one huge window, roughly the size of a tennis court, has been com pleted. Others are in various stages of refurbishing. According to Cole, the qualities so many people admire in medieval glass are due to the aging process. "With age the stained glass the people's faces become seamed, anil they take on more character and beauty," he said. "The problem we face with the restoration is deciding how far we should go in re storing the windows to what they were originally." One ol Canterbury Cathedral's centuries-old leaded stained glass windows is dismantled in Preparation tor restorative treatment. Restored Canterbury stained glass is reassembled and joined with encient recycled lead. Lead brick walls The design of spin pits for rotational absorb high speed impact of spin testing is not standardized. Since they must be used for a variety of products, each is designed accordingly. Among test debris the industries involved in this form of testing, aircraft companies are one of the largest. For example, Pratt & Whit Today's high-speed production lines ney uses a testing pit extensively at its call for steel wire to be fed off reels North Haven, Conn, plant to test such as fast as 16.000 feet per minute (ft/ aircraft components as rotational ele min I. At such speeds, the reels are sub ments for gas turbines. Another Con jected to tremendous centrifugal forces necticut-based firm, AKO, performs spin that could cause them literally to be torn pit testing for other companies on a sub to pieces. Sections of the reel would contract basis. And Worthington Pump, then be hurled in all directions at very Buffalo. N.Y., uses a spin test pit to high speeds, which could injure workers check high - peed impellers for pump and damage production equipment. systems. To make sure reels can withstand the extreme centrifugal forces, they are tested to the point of self-destruction, usually at speeds beyond those they would normally encounter in actual pro duction. Such tests are conducted in specially designed circular enclosures called spin pits where speeds approach 24,000 revolutions per minute. When reels destruct at such speeds, sections are hurled at the spin pit walls with a tremendous impact. To absorb this enor mous amount of energy, the walls are lined with lead bricks. A wire reel industry "first" Mossberg/Hubbard, a major U.S. sup plier of reels and spools for the wire industry, recently installed its own spin pit for testing its products.-The New England firm is believed to be the only wire reel company to have such a fa cility. Previously, spin testing was ac complished by outside sources on a sub contract basis. According to Paul Paulsen, chief en gineer of the company, faster produc- tion rates in the wire reel industry are putting harder demands on ^ "WTt inreo sapeuecduss inn tmhe miinlls tooddaayy ' ^ greater than in the recent past." "F~oor example. 10.000 ft/mmiin is ^ mon today as 5,000 ft/min was^c*1' years ago. And no. 34-gage wire sq J** times travels at as much as 16q q q ft/min." The new spin pit is 45-in. wide 28-in. deep. An air-driven turbine can ble of 25.000 rpm is mounted on ^ cover of the pit. Reels are fastened to an arbor which is suspended from t|,f turbine spindle. After the spindle j, secured, air is pumped out of the chan,, ber to avoid w indage on the piece being tested. Several thousand pounds of 4x4x8.^ lead bricks were used to line the hi terior of the pit to absorb the energy from flying debris when there is a reel destruct during a spin test. Fragments are imbedded in the lead, which pro. tects the rest of the interior. The Pjn. thick lead bricks are enclosed with three concentric cylinders of armor-plate steel and cased in reinforced concrete. The pit is large enough to accept a 36-in.-dia. reel weighing up to 500 lb. Controls provide a digital readout for rpm, plus a paper tape printout to validate or certify speeds reached. Lead bricks lino spin test pit at Mossberg/Hubbard to absorb impact of wire reel sections when they self-destruct. Before and after photo shows result of spin testing standard 8-m. G-type w/re reel at 23,752 rpm, which is 386 percent over normal running speed. LIA26810 l^ead cuts cost 0f underwater sound systems The substitution of lead for silver in 3 water-activated battery that powers iophtsticated underwater sound de- ,tion device is saving the l .S. Navy ,L,nsiderable money. The conversion has accomplished without sacrificing ,|jf capacity, dependability and efficiency , the devices, known as sonobuoys. -tonobuovs are air-dropped into oceans l0 detect and track nuclear submarines. \fter serving their purposes, the de ices sink to the ocean floor where the , Suable silver cannot be economically recovered. Although each battery con tains only an ounce of silver, the Navy expends several hundred thousand sonoOuovs each year. With the current price jf silver running about $4.40 an ounce. SuOstitution of lead for silver in water-activated battery (inset) tor underwater sound detection devices known as sonobuoys is saving the Navy considerable money. the cost becomes significant. Now a magnesium lead chloride bat tery has been developed that is a viable alternative to silver in the simplest sonobuoy system. The inexpensive lead chloride costs 6 cents an ounce, and only two ounces are required for each battery. This brings the cost down to only 12 cents per battery, a saving of about $4.28 per sonobuoy. The simplest sonobuoy consists of a non-directional hydrophone, an audio amplifier, a radio transmitter and a battery. It is activated when sea-water floods the battery compartment. The battery powers the transmitter which transmits submarine sounds picked up by the hydrophone to the aircraft above. The battery also initiates action that sinks the sonobuov after use. This ability to pinpoint the location of a submarine nullifies its inherent ability to avoid detection. Source: ESS, Inc. Solar energy provides in-place corrosion control for underground electrical cable Solar power and a special lead-acid battery are proving to be an effi cient combination for Florida Power Corp. The utility's problem was insuring that a new mile-long 15kv lead sheathed cable feeding power to downtown St. Petersburg would not suffer from gal vanic corrosion. Such corrosive attack could in time eat through the cable's protective sheath and subsequently cause electrical failure. The 4-ft. burial depth of the cable only served to aggravate the problem, :ince this depth is below the water level for the coastal area. Moisture in the soil is one of the factors responsible for galvanic corrosion. When this moisture combines with the soil's corrosive chem icals it forms an environment that, in time, creates an electrolyte which causes an electric current. Although cable en gineers agree that lead sheath is still the superior cable protection, under these conditions even lead could corrode to-' the point of failure. Florida Power turned to its major product, electricity, for the necessary solution. In this case however, the elec tricity was supplied from a source out side the utility's own generating facili ties. For some time the company had been investigating the feasibility of using solar energy to meet various needs. Research had indicated its suitability for this particular application. Photovoltaic cells supply power Installed at the utility's 16th Street substation in St. Petersburg, the elec tric power comes from a system of photovoltaic solar cells. They convert sunlight directly into electricity which is Solar-powered rectifier feeds 30 wcfr* a/ 9 volts d-c to ISkv underground cable to minimize galvanic corrosion. LiA26811 applied to the sheathed cable. The pro tective sheath, which could experience considerable corrosion in a short time, will reportedly last indefinitely with the application of the galvanic-current neu tralizing charge. The silicon-filled solar cells convert sunlight into electric energv without the use of any moving parts. The electrical output of 30 watts is greater than that required to generate the desired current. Therefore, the excess energy is diverted to a special 6-volt, 200 ampere-hour ca pacity lead-acid storage battery. The battery provides the energy require ments during the night and on days when cloud cover prevents the photo voltaic cells from functioning. After a 12-month study of the effec tiveness of the solar-powered rectifier, Florida Power has determined that the application is a trouble-free, effective method of corrosion protection in ap plications such as this. The solar device, which cost the utility $1,300, is a small price to pay for the protection it pro vides. It would be far more costly to dig up the mile-long cable for repair if problems developed. The device is the same type used by the Coast Guard to light marker buoys in marine navigation channels and, more recently, to power a lighthouse at Key Largo. The National Park Service uses photovoltaic cells to power moun tain-top radio-repeater communications facilities. NPS also has experimented with photovoltaic solar cells to recharge batteries used to power electric work and personnel transportation vehicles. 7 Major paint specifiers rely on lead-based New York City, famed throughout the world for its theaters, mu invariably specifies lead-based paints to achieve these goals. And, because TBTA seums, shopping and restaurants, is also maintains so many bridges, other agen Whitestone, Henry Hudson, Cross Bav Veterans Memorial, Marine Parky,,', and the newest, Verrazano Narrow^ known for its bridges. The maintenance cies with like responsibilities look to it the Throggs Neck is being coated Kith of many of these bridges connecting the for guidance in paint specification. blue-grey paint. This color was select^ various boroughs that make up the city is relegated to the Triborough Bridge TBTA favors lead-based paints because it blends with the sky and yater TBTA reports that a key element j,, , and Tunnel Authority--better known TBTA officials report that, in so far the paint system used for its bridges is by its initials--TBTA. as maintenance painting is concerned, lead silico chromate. It is a highly effer. Because of the waters they span and lead-based pigments will perform better live, anti-corrosive, weather resistant their exposure to rain, snow and fumes, at a given cost than other paints on the protective pigment. The lead content of the seven bridges maintained by the market today. They have been using the pigment provides a compatible and TBTA are continually under attack by these paints for over -10 years. The lead- durable paint system that not onlv offers corrosion. New York also is an area based products require minimum sur superior protection against corrosion. , where salt-laden Atlantic Ocean and face preparation and the cost per gallon but also helps the painted areas retain a Long Island Sound mists and fog add is less than most other paints. "just painted'' appearance. The lead. , to the corrosion problem. The road salt Typical of the TBTA bridges is the based paint is used both in prime and ( and sand dispersed during the winter Throggs Neck, situated in the North finish coats. also take their toll, particularly along eastern section of the city, spanning the As an example, prior to the npenin; side barricades and roadway center East River. It connects the mainland of the Verrazano Narrows Bridge in I dividers. borough of the Bronx with Queens on November, 1964. the entire steelwork One of TBTA's responsibilities is to Long Island. To the east lies Long Is was coated with three or more coats of 1 specify a paint system that will offer land Sound, and beyond, the Atlantic basic lead silico chromate paint. Areas maximum corrosion protection for the Ocean. included the 70-story towers, and struc- ^ bridges under its jurisdiction and at Like the six other structural steel tural steel for the twin decks. In addi * the same time provide a good overall bridges under TBTA jurisdiction--the tion, about 5,300 gallons of red lead decorative appearance. The Authority others being the Triborough, Bronx contained in a linseed oil paste was ap- L V to guard steel structures against corrosion plied to the more than mile-long cables .upportins: the bridge. In April, 1974 bridge was re-painted during a twou-ar program ending in September. 1976. A total of 8.000 gallons of spot .,,Lit and 84.000 gallons of finish coat ,,as utilized. Lead also used by Port Authority Other bridges in the \ew York area are maintained by the Port Authority of \>w \ork and .Yew Jersey. The Port Authority favors lead-based paints for the primary coating of steel structures for the four bridges under its jurisdic tion. They are the George Washington, Ooethals. Bayonne and Outer Bridge Crossing. These bridges are prime coated with a pre-mixed red lead/iron oxide paint. The top coat is alkyd-aluminum. The painting operation consumes eight months of each year. Maintenance of the various areas of all bridges is per formed on an individual cyclical basis. TA likes lead protection too Lead-based paints are also playing an important role in maintaining Yew h ork City's subway system. The City's 21 subway lines carry about 3,500,000 passengers per day on 230.64 miles of track that snake through four of the City's five boroughs--Manhattan, Bronx, Brooklyn and Queens. And in some areas the subway becomes elevated, emerging from beneath the ground to rise above the streets. The 70.82 miles of elevated track, more commonly called the "el", are supported by a massive network of structural steel girders, beams and joists. Like the City's bridges, these structural members are exposed to dirt, grime, rain, snow, auto fumes and in some cases industrial pollutants. Yew York City's Transit Authority I TA I has been specifying lead-based paints for these structures since they were first built in the early 1900's. A spokesman for the TA reports that the paints "provide an excellent rust inhibitive coating over the metal and that they can be applied with a minimum of surface preparation. Their value as an anti-corrosive covering lies in the fact that lead-based paints retain their corro sion resistance regardless of the sur rounding environment." According to the TA, the red oxide primer consists of 74 per cent red lead, and 23 per cent red oxide. The remain ing paint system is synthetic resin solids, linseed oil. and dryers. Painting the 70.82 miles of elevated structures is not a job that can be com pleted quickly. Considering the vast size and amount of structural steel involved and the number of times that paint crews must move ladders and scaffold ing, it is not surprising that just about four miles of elevated structure are painted a year. The TA estimates that about 3,180 gallons of lead paint are used for each mile of typical three-track structure. Be fore applying the lead-based paint, crews scrape badly rusted areas with wire brushes. Following application of the primer a tan alkyd aluminum finish or top coat is applied. Slue-grey paint used to coat steel structure ot Throggs Neck Bridge hes '*ad sillco chromate base to ward off corrosion. t l Wave soldered PC boards enhance process control reliability Faced with increasingly complex quality problems and increased pro wave soldering. On many of the boards the circuitry is incredibly dense and duction rates, many high volume process complex. A single board might contain industries are now using computerized up to 100 joints to be soldered. Each production control. Computer reliability type of board is processed at a precise helps eliminate costly errors in the pro speed in order to achieve the correct cessing of food, beverages, chemicals preheat temperature and solder wave and scores of other products whose com dwell time. The machine can accommo position must meet prescribed standards. date up to six boards at once and up to Introducing computerized process con 75 boards an hour can be soldered. The trol can be expensive. So some com exact totals depend on board size and panies are turning to special purpose configuration. analog computer techniques involving devices called function modules. A rela tively inexpensive method of computing, involving current and voltage-regulating circuits, these devices are highly reliable Soldering is accomplished in a matter of seconds with one pass of the board over the solder wave. And the precise quality control attained has increased and can be installed as needed, much like building blocks. Each module per forms a specific function or group of functions while operating independently or in conjunction with others. A key element in the high reliability of analog computers is the built-in quality, long life and virtually mainte nance-free operation of the printed cir cuit (PC) boards that are the nerve centers of these units. The key factors in joining PC board components are speed, efficiency and economy. Often these fac tors can best be attained through the use of wave soldering. For example, at Bell and Howell's Control Products Division, wave solder ing is being successfully employed to mass produce high quality PC board as semblies for function modules used by the process industries. Initially, wave soldering at the Bridgeport, Conn, plant --i was limited to one bench-type machine which handled only one type of board. The rest of the boards were hand sold ered. Now the company has a large machine made by Electrovart, Inc., Mt. Vernon, N.Y., featuring a 15-in.-wide wave and the capacity for soldering a variety of boards. PC board reliability five-fold to Gemza. CCor(ling System involves three steps The company's wave soldering three-step integrated system. It * of fluxing, pre-heating and the soldeZ** A 12-ft. long conveyor carries the 0^*' mounted PC boards through the sold!! ing process. The conveyor is inci^.' 3`g degrees with respect to the sold* u a\e for optimum soldering ellicie ^ Rosin-based -foam" fluxing employ!) in the initial step of the process gives^ complete and uniform coating 'o ti! solder side of the PC boards and hances the wetting action of the sold'!' Wave soldering, proved beneficial Roger Gemza, plant and manufactur ing engineer, reports that the transition doubled production capacity without the need for plant expansion. "We also realized $10,000 a year in direct labor cost savings," he said. "And the ability to mass produce, PC boards by wave soldering upped productivity 10 percent the very first year." Over 220 different PC boards, rang ing in size from t/o-in. x 2-in., to 8-in. x 10-in., are joined and connected by Bell and Howell worker places printed circuit board in pallet on Inclined conveyor which will move it through various wave soldering atepa. At right, electronic components ot PC board are solder-joined in seconds with one pass over solder wave (circled area). i 10 LIA26814 ,y pre-heating step brings the boards 1 w an average temperature of 160F. serves to evaporate excess solvent Eye-catching bank lobby pool based with lead ` (jre boards and to condition the as- ' ,l)ly against thermal shock as the Jjrd touches the solder wave. (_'e of 63/37 tin lead solder permits ,pid joining of the board componentry ! ,he lower practical temperature. The ,|der bath temperature is maintained at hout 300" F and normally the wave 'eiaht is U-in. fhe bi-directional solder wave applies ,/der to the conductor surfaces and jjjit areas of the workpiece, promotes ^t wetting and aids capillary penetra- ,j0n. The velocity of the solder flow is h^hest where the board enters the wave ;0i the most efficient heat transfer, rap- jlv elevating the board to soldering ,fInperature conditions. As the PC as- .emblv moves up the wave incline, the low velocity decreases, accompanied by ^creased wave pressure to provide good capillary rise and through-hole penetra tion. The board exits at a point where the relative velocity between board and colder approach zero to eliminate icicles, bridging and excess solder deposits. The soldered PC boards are cleaned later with a fluorinated solvent, after b which they are inspected and any neces sary touch-up performed. Gemza reports that the high quality obtained through wave soldering has resulted in lower inspection levels and a 50 percent re duction in costly and time consuming touch-up. A decorative pool with fountain-sculpture dominates the Centre Square Lobby of the First Pennsylvania Bank Building in Philadelphia. Although visitors are impressed with the futuristic freeform, many are somewhat mystified as to what the sculpture is supposed to represent. According to Christopher Ray, the artist responsible for the work, the two wrought copper sculptures depict the Maine coastline. The larger of the two is called ``Ebb Tide" (low tide). ``This part of the sculpture suggests the calm mysteries of the intertidal world," Ray explained. ``The smaller part, known as `Neap Tide' (high tide), depicts vitality and strength," he added. Most visitors also are unaware that lead plays an important though unseen role in keeping the pool water-tight. A total of 3,724 lbs of lead lines the pool to contain the constantly circulating water. The 5-ft wide by 25-ft long pool is really divided into two sections, since the lobby is on two levels, with a 2-ft elevation difference. Water from the upper level pool spills down into the first level section. Each pool, is 16 inches deep and faced in polished granite. The bottom consists of 4-in by 4-in square clay tile. i The pool lining was installed by two lead burners from Baltimore Lead Burning Corp., using lead supplied by Devine Bros., the contractor. For the exposed areas 8-lb lead was used, while 6-lb was employed under the granite. The lead, which contains -4Vi percent antimony and 0.08 percent arsenic, was installed in 8 strips. Sheets ranged in size from 3-ft by 14-ft, to 8-ft by 20-ft. About 125 lbs of lead burning bar was used to join the sheets. Initially, the concrete base was thoroughly cleaned and covered with a cold- applied brush coat of bituminous coating. This was followed by asphalt-impregnated felt. After the sheet lead system was laid down, a 24-hour hydrostatic water test was conducted to check for leakage. Another layer of bituminous coating was then applied before the granite and clay tile were installed. First Pennsylvania Bank officials are confident that the pool, which was designed by Brown & Goldfarb of Philadelphia, will maintain its water-tight integrity, thanks to lead. LIA2&815 11 Leaded products combat noise on several fronts There is a rising concern amon* . I dustrial hygienists that occup,,^". or work-related noise may be a se ' general health hazard, creating divU! physical ailments in addition to heari* damage. A number of these experts M that noise can be the basis for vari ** psychological problems as well \j * and more this form of pollution is considered as an insidious danger unrecognized by its victims. Faced with growing evidence of noi hazard, labor unions are pushinz hard for stricter compliance to the 90dB nois<. exposure level established in 1970 under the Occupational Safety and Health OSHA). In many cases lead, in combination with other materials, has proven to be an effective means of reducing noise to within the permissible OSH^ limit. Here are some wide-ranginz ex amples. Remote control room af Dow Jones' Orlando, Fla. plant has lead laminated panels and double-glazed glass to shield operators from press noise outside. 12 LI A 26816 ^ushthe presses \t Orlando. Fla., Dow Jones & Co. is rinting Wall Street Journals for day j publication distribution in the South- bv means of a satellite communica tions system. Facsimiles of full-size journal pages are transmitted to Orijndo via satellite from another Dow jones plant in Chicopee, Mass., where tjie newspaper is set in type. The Orlando plant, which is said to be the first of its kind in the world to produce newspapers by this '`facsimile via satellite" system, also features a rem0te control room for the printing press. Shielded from outside noise by laminated lead panels and double-glazed jjass, operators work in a substantially quieter environment. Press speed and jlov.' of ink and water are regulated from a specially-designed console in the room. The noise level outside of the control room averages L07dB, compared with an average of 87dB inside. This salutary change is effected by a 1/16-in. thick lead sheet sandwiched between two sheets of dry-wall board on three sides of the room. Sound attenuation is achieved on the windowed front wall through double-glazing, with thicker acoustical glass on the outside backed by conventional safety glass. The re duced noise level keeps press operators healthier and happier. Pipe forming machine noise curtained off At Interspace Corp., Wharton, N.H., a 50-ft. long lead-vinyl barrier curtain helps protect employees from the noise of four concrete pipe forming machines. The installation has reduced noise at these machines to the permissible 90dB level from a previous 105dB reading. The problem presented by this par ticular application was complicated by two factors. Any noise control installa tion would have to allow the machines to be fully exposed for the entry and positioning of concrete forms by an overhead crane and exiting of the fin ished reinforced pipe. In addition, the machine operators had to view the placement of the concrete poured into the rotating form. The customized noise control system, jointly designed by New Jersey Safety At left, open view of leaded-vinyl noise barrier Curtain shows swing-away overhead track which permits easy access by crane. Closed view of curtain (right) srtows safety window which enables machine operator to monitor manufacturing process. Equipment Co., and Singer Partitions, consists of six 34-lb. per sq. ft. acous tically engineered leaded vinyl curtains. The 10-ft. high curtains are suspended from an overhead track-and-roller sys tem, attached to a steel framework. W'hen closed, the curtain barrier covers the 50-ft. length of the machinery area. For machine access, a hydraulic sys tem swings the overhead track sections out of the way to permit entry and exit of the crane. When closed, the operators view the manufacturing process through safety windows installed at set intervals along the curtain wall. The 15dB noise reduction achieved has considerably lowered physical risk to employees. Ship engine noise reduced upto15db When ships are at sea, engine room noise is often considered something that must be endured since you can't walk away from it. On small-class vessels, the noise level can be relatively high at any point, including living quarters and on the bridge. On two U.S. Navy Weapon Retriever boats in use by the Pacific Missile Range Facility, Port Allen, Kauai, Hawaii, noise levels from the engine rooms were in excess of the 90dB limit. OSHA ex posure criteria for noise levels of 95dB measured on the bridge of both ships should have permitted th&Tctvws only four hours of exposure per day. Actu ally, they often remained at those duty stations for much longer time periods. After General Acoustics made an indepth sound survey on each boat, a three-step approach was taken to solve the problem. 1. Existing mufflers and exhaust pip ing were replaced. 2. Exhaust piping from the engine manifold to the exhaust exit was in sulated. 3. The engine room bulkheads, hatch covers and interior hull surfaces were lined with sound attenuating material. When the new muffler sections and ex haust pipe were installed, vibration iso lation was provided between the pipe hangers and clamps used to secure the piping to the interior structure. General Acoustics then covered the piping with a 2-in. thick layer of 8-lb. per cu ft high temperature insulation material, com bined with a sheet lead barrier. The outer covering consisted of light gauge aluminum sheets secured with stainless steel straps. Sound attenuation in the engine room was achieved by the use of a lamination of fibrous acoustical material and sheet lead. This material, which was made up in sections called "sandwiches," was bonded to the engine room interior sur faces between the bulkhead stringers. A perforated sheet metal shield was placed over the acoustical material and riveted to the stringers. Sound surveys were again made on the bridge of each boat with both en gines at full load. The noise level on one boat was 82dB, compared to the previ ous 95dB reading. The noise on the other vessel was reduced from 96dB to 81dB. In addition, an 8dB noise reduc tion was achieved inside both engine rooms. 13 Lead helps provide fast curing for painted products sheet lead is the most effective radiation material available for such equipment. EB is still not generally used for cur ing finishes on metal and plastic parts, although Ford Motor Co. is using it for interior plastic applications. However, auun ui c benefits. Companies that produce painted products cannot tolerate long dry ing times. Production lines would be come backlogged and distribution would be delayed, both costly situations to be avoided. To sohe the paint drying problem, a system called thermal curing was de veloped. The system is also used to cure ink and other industrial coating mate rials such as adhesives. However, ther mal drying facilities are becoming in creasingly expensive to operate in view of the high price of natural gas. crude oil and electricity. They also occupy an inordinate amount of space. So indus try has turned to more sophisticated techniques to achieve quicker, more economical curing cycles. One of the newer curing techniques cylindrical component in upper center q 1 the photo. Cylinder is totally encased in lead. Inset drawing shows greater detail. (Drawing courtesy of Machine Design.) is the electron-beam (EB) method, which often involves the use of lead radiation shielding. In the process, low energy electron beams are directed onto Lead shot solves veterinary problems the surface to be cured. This effects a near instantaneous cure over the entire width of the product, providing its width is within the capabilities of the system. EB lines are generally faster--up to 2,000 feet per minute (ft./min.) than another recently developed system of radiation curing involving ultraviolet rays (UV). In addition coatings for EB may cost as much as 15 percent less than those for UV curing. EB also has a distinct energy advan tage over thermal curing. To illustrate, an EB curing unit now on the market reportedly consumes only 68,000 Btu per hour for a 48-in. wide line operating at 500 to 600 ft./min. On the other hand, a thermal curing station operating under the same conditions consumes At left, Or. Thomas P. Nytch positions Doberman Pinscher prior to radiographing her injured leg. Photo at right shows how 25-lb bags ol lead shot effectively immobilize animal during X-ray procedure. 1.5 million Btu per hour. Lead supplies radiation shield While EB curing units consume less The remarkable growth in pet owner ship in recent years has put increas ize the patient in certain body or limb positions. ing demand on veterinary services. Many veterinarians purchase spe energy and increase production curing These doctors must rely heavily on the cially-prepared, leather-covered bags of cycles, the high-velocity electrons emit use of radiographic equipment to de sand for this purpose, or resort to other radiation. For this reason, manufactur termine the extent of animal injuries, homemade devices. One sports-minded ers of EB units, must provide sufficient and this can create problems. physician in Vestal, N.Y. discovered that shielding to protect workers. In most For one, veterinarians often have dif 25-lb bags of lead shot provided a prac cases this protection is achieved through ficulty positioning their patients. Unlike tical solution to the problem. The bags the use of lead. humans, animals will not hold still in not only offer advantages over alternate For example, Energy Sciences of Bed specific positions during X-ray expo methods, but the lead shot can later be ford, Mass., uses two layers of %-in.- sure. Therefore, they must be anesthe recycled to reload 12-gauge shells for thick sheet lead for radiation shielding tized and made as immobile as possible. skeet shooting and hunting. for one of its new 54-in.-wide EB pro This can require the animal to be held, Dr. Thomas P. Nvtch of Vestal Veter cessors. Total weight of the lead shield which exposes the doctor or his assistant inary Hospital found that the lead shot ing on the unit is about 1,300 lbs. Ac to the dangers of radiation. Or some bags are heavier but smaller and more cording to Energy Science engineers, 14 heavy object must be used to immobil flexible than the sand-filled type used LIA26818 ;ot the -amp purpose. This differential irowhes greater holding force in a jailer space. For a large dog the added nt,jght is especially important to hold |,ead. leg and body positions. For a nialler animal, the bags offer more free- jcrn fr positioning a particular part. 311d make it possible to use more than one bag in a closed-in area. The lead shot also prevents unwanted \-rav exposure on the film and the animal bv proper positioning of the bass on the table and the patient. In addition, it aids in post-operative and post-accident therapy. Since many four legged animals tend to favor a bandaged or hurt leg. veterinarians often weight the foot to encourage normal use of the limb. The use of lead shot arounc^he contour of the foot enables a smaller, neater bandage to be used. Dr. .\yfch finds the package to be less bothersome, so animals are not inclined to attempt to remove it. Veterinarians who do not reload shotshells for sports activities can merely re cycle the lead shot into new cloth bags whenever necessary. Either way. lead shot bags offer radiation protection and concentrated weight in a soft, flexible form for more efficient animal diagnosis. VVho says a lead balloon can't fly? That old phrase "It went over like a lead balloon" has been put to rest So they set out to prove that "`going over like a lead balloon" is really an bv the research and development firm outdated phrase. 0{ Arthur D. Little, Inc. (ADLl. Three teams of designers from the firm's \corn Park headquarters in Cambridge. \[ass.. recently undertook the unique task of constructing lead balloons. And, believe it or not. thev Hew . . . just like T hree different types of lead balloons uere constructed. One was a traditional limp sphere, another an endoskeletal sphere shaped much like a watermelon, and the third a cubistic unfolding square, resembling a giant pillow. real balloons! All three ADL balloons featured a. The company was founded on the lead foil exterior. To disprove the point premise of accomplishing the "impos that lead's so heavy it can't "fly," the sible on impossible time schedules'' and, round balloon weighed 12.9 lb. (5.8 kg.), more often than not. does it. Therefore, the elongated balloon weighed 27 lb. the staff has an ingrained distaste for (12.3 kg.) and the cube, 30 lb. (13.6 kg.). shibboleths about what can t be done. Filled with helium and launched from the ADL parking lot. the balloons actually flew! The cube balloon rose about 10 feet in the air. developed a rip in the seam and fell back to earth. The traditional sphere ascended, slipped its mooring and sailed across the highway into neighboring Arlington. The 14-foot-long endoskeletal balloon, which was filled with 463 cu. ft. of helium, also broke tether. It was last seen heading out to sea, the uncontested "winner." So the next time you spot a silvery looking object in the sky. look closely, it could be a helium-filled lead-balloon on its wav to the moon. A? left, Arthur D. Little designers construct balsa wood skateton tor 14-ft. long endoskeletal lead balloon shown at right. This balloon, one of three constructed by the firm, was successfully launched. Q FOR CHANGE OF ADDRESS PLEASE ATTACH OU> MAILING LABEL. (please check one) To . Name, Titla Company Street City, state, zip code G AOO ME TO YOUR MAILING LIST PLEASE CHECK INTEREST Q Painting G Health & Safety G Architectural & Building Q Design & Radiation Engineer* G Ceramic* Chemical Engrs. Q Battery Power Miscellaneous (please specify) *15 ARCHITECTURAL Lead Roofing and Flashing Detailed instructions on the simplest and most usual methods for forming or join ing lead for roofing and flashing appli cations. Complete specifications. Dia grammatic drawings. Sixteen pages. A-S "Solder Puts It All Together for Manufacturer of Zippo Lighters" Two-oage reprint from Production Maga zine details production soldering of light ers at Zippo Mfg. Co. 1-7 Soldering of Electronic Products BATTERIES A Primer on the Lead-Acid Battery A condensed story of the principles of the lead-acid battery and its chemistry, in cluding some of the fundamentals and definitions of direct-current electric en ergy. Two pages. L-6 Lead, "The Cinderella Metar Booklet is reprint of talk atvmn . First National Conference on Availapility/Utilization. K c h *"*** President. Noranda Sales'co^o dian lead producer, discusses an- pricing trends for the metal ana 2y >r* Sizes Its Signficance and valuel Lead in Building A four-part data sheet containing informa tion on waterproofing, sound Garners, roofing and flashing and anti-vibration ap plication. A-13 CERAMICS Facts about Lead Glazes for Art Booklet covers use ol t 'oad solder as a highly retii * |0..nng ethod in the electronics mdLstry. It includes informa tion on the control of electronic assembly components for soiderabihty, fluxes and flux residue removal, solder alloys and soldering methoos. 1-8 SOUND BARRIERS Electrics Get Key Post Office Tests Reprint of a feature from Electrical World describing tests on the suitability and economy of electric battery-powered de livery trucks for the Postal Service. L-18 Electric Work Vehicles A 12-page folder describing battery, powered short-haul delivery vehicles and comparing their economics to internal and m the future M-3l ooth nw Leaded Grades: Answer to Free-Machining Needs Reprint reports on hhe.rneli,, ae,lvM , using leaded steels, ffoorr tfrreeee mniaacchhlinninT rr.v.' i?Case histories are =-- -- -- - - strate that these n partsmakers to raise productic>oaonnr* ofenqaubblle(f " omy. M-32 -'"h "ioien"ccvy aannaa COfl. Potters and Hobbyists Detailed information on the proper formu lation. firing techniques, handling, etc. of lead fluxed glazes used by art potters and hobby ceramists, illustrated. S.xteen pages. B-ll Directory of Acoustic Specialties Summary of available materials for sound insulation by barrier, damping and ab sorption methods. Sixteen page list of materials by brand name and manufac turer. Eighteen pages. J-4 combustion delivery trucks. L-19 Battery-Powered Industrial Trucks Spark Energy and Cost-Savings This 16-page booklet offers an in-depth iook at the many factors favoring the pur Lead and Zinc Outlook 19?6-t 9EQ Booklet examines demand prospect* production for lead and zinc over the .i four years. Current markets and gr0J application, are also discussed. IS oag? Proceedings of First International Conference on Ceramic Foodware Safety Top international experts m ceramics, Food and Drug agency officials, and the international lead research community met m Geneva m November. 1974 to dis cuss neavy metal release from glazed ceramic foodware. Full proceedings-- speeches as well as question and answer dialog--were taped, translated and tran scribed 272 pages. B-13 Lead a Major Factor in New Machinery Noise Suppression Systems Description of techniques used to lower machinery noise levels with lead and lead composites. Lists machines that normally exceed noise level allowed by Walsh- J-9Healey Public Contracts Act. Two pages. Sheet Lead Plenum Barriers chase of electrics for industrial applica tions. A pull-out set of work sheets allows the reader to determine how electrics stack up against 1C types m his own oper ation. L-22 Saving Battery Dollars--What You Need to Know Three-part reprint from Modern Materials Handling deals with proper procedure in picking the right battery for the truck and iob. <t also discusses considerations in battery charger selection. The third part offers guidelines for pluwMg an efficient Occupational Lead Poisoning , It Needn't Be ... A Manual for Manager* Contains information of use to the mdu*. trial manager on the safe handling of lead and lead products m industry Ty,,*' and permissible levels of occupational lead exposure are discussed. Some orac ticai controls and safeguards are lu. gested. 16 pages, bibliography. M-U *' Lead and Your Health PAINTS Lead Pigments Bulletin Detailed description of acoustical plenum barriers and how to install them. Mate rials and installation procedures de scribed and illustrated. Eight pages. J-10 battery charging-room laydBE L-23 Electric Vehicle*: State-of-the-Art 1978 Brochure contains advice on occupational protection against over exposure to lean A checklist of good health practice* ,< ncluded. M-35 *!> Brochure, 12 pages, describes the advan tages and varieties of lead pigments in anti-corrosion paints. Covers red lead, dibasic lead ohopshite. basic silicate white lead, basic lead phosphosiiicate. basic lead chromosilicate. basic lead silico chromate. Lists maior suppliers. F-7 Practical Application of Sheet Lead for Noise Barriers Discusses how the use of various thickneses of lead bonded to or used in con junction with other construction mate New 28-pagS booklet contains latest data on electric trucks, buses and passenger cars around the world. Case histones de scribe EVs in a variety of work applica tions. Other sections cover energy crisis and pollution problems and their effect on EV's; and the role of lead batteries m Old Paints and Rural Lead Poisoning 8ooklet discusses the incidence of le^ poisoning among children m mau to*,** and rural areas, a problem usually asso ciated with b'g cities. Th* need for lead screening programs to detect and correct rials determines the Sound Transmission EV development. L-24 the problem is emphasized. M-38 CHEMICAL CONSTRUCTION & CORROSION PROTECTION Lead for Corrosion Resistant Applications Soft cover book. 156-pages, designed to familiarize engineers and engineering students with the corrosion resistance, design and fabrication data on lead and lead-based equipment. Defines plumbum Class (STC) rating of walls and partition*. J-15 Lead Proves a Heavy Favorite as Sound Control Material A reprint of a feature from- Product Engi. neenng illustrating lead's usefulness m sound attenuation to help meet OSHA noise requirements in factories and also on planes and trains. J-17 GENERAL "Lead Abstract*" and "Ytarly Indicts" Bi-monthly abstract of alt current world literature on lead and its products *nd published research. A general mljji Ti published annually. Must be reqi~ on company letterhead. M-2 Primary Lead Production Areas Directory of Lead Casters Booklet lists 58 companies throughout the U S. that produce lead products for industry. Data on each firm includes typ* of casting method, products produced and auxiLary services offered. A contact name at each company is provided. M.J7 FILMS Lead in Motion** series and corrosion resistance of series. H-6 Lead Chemicals Soft cover book. 334-pages, is designed as a working manual for the chemist or chemical engineer engaged in applied technology or pure research. Covers organolead compounds, oxides and hydrox ides. sulfides and teilurides. halides binary compounds, lead salts, lead chel Specifying Lead for Noise Control Eight-page reprint contains guidelines to help architects and engineers fully utilize the advantages of lead as a noise control material. A number of case histories are included to show how some of these guidelines were used to solve a variety of commercial, industrial and residential noise problems. J-18 in tha U.S. For schools, libraries. Il"xl4' map show ing locations in U.S. of most lead smelters and refineries, and lead mines. M-ll 4 The U.S. Lead Industry An annual review of activity within the industry that contains a general summary for the year and a series of charts and tables giving current statistics oa lead A 21-min., 16mm color film. Lead's prop, erties and its potential for unlimited fu ture applications are explored from the viewpoint that an atom of lead--like all elemental matter--is an arrangement of energy--part of a universal system. To order specify desired.show date and one alternate date. No- charge to borrow; viewer pay* only return postage. N-2 Occupational Lead Poisoning ... ates. safety in handling compounds. Pur production and consumption. M-14h It Needn't Be chasing price: $3.00. H-7 SOLDERING AND WELDING Solders and Soldering New 16-page booklet filled with basic in formation on soldering and the selection of the right solder alloy for the applica tion. Data is presented on a variety of tin lead as well as other solder alloys. Sev eral case history treatments of typical soldering applications are included. 1-0 The Use of Absorber/Barrier Materials for Noisa Control Enclosures Four-page reprint is concerned with noise abatement applications within the 10 to 15 dB range. It describes an installation using a quilted absorber/barrier enclo sure suitable for achieving these reduc tions, and presents the advantages of this material. Acoustical, economic, oper ational and maintenance aspects are con sidered. J-19 Lead--a Modern Design Material Summary of properties and available forms of lead for radiation' control, sound/vibration control, electrical energy sources, soldering and ceramics. Eight pages. M-15 Ecology in the New Lead Bart Reprint describes cooperation of industry and environmentalists in developing southern Missouri lead mines. Four pages. M-23 A 16mm, 15 min., sound color film. N*r- .rated by the environmental health experts international calibre, the film intro duce* th* basic principles of a health pro gram for th* lead industry. The intention is to motivate the cooperation of both management and employees m develop ing an effective health program for their particular operation. To order, specify de sired show date and allow one alternate date. Allow at least five weeks for de livery. No Charge to borrow; viewer pays only return postage. N-3 Printed in U.S.A. PLEASE SEND ME THE PUBLICATIONS MARKED BELOW WRITE IN CODE NO.