From Darkness to Photoelasticity

The Voyage Begins

"Cast your bread upon the water, for you will find it after many days" (Ecclesiastes 11:1)

Felix Zandman was born to Aharon and Genia in 1927, in the town of Grodno, formerly in Poland (today in Lithuania). His father was a scion of a family of learned but penniless yeshiva students, who spent most of their time studying the Holy Scriptures. In the house of his grandfather and grandmother – Berl and Rebecca Zandman – table conversations used to revolve around the weekly Torah readings, the Talmud, and even philosophy and Zionism. Felix's grandfather on his mother's side, Nahum Freidovitch, belonged to a family of wealthy industrialists who owned a construction materials business.

Aharon Zandman, a Socialist Zionist, was a chemist by profession, who received his Ph.D. from the University of Vienna. At the time, Polish Jews were not allowed to teach or research in universities. Since he was wed to the daughter of the affluent Freidovitches', Aharon had to make do with the position of a junior partner in the family business.

A couple of Polish peasants, Jan and Janowa Puchalski, maintained the Freidovitches' summer residence. Nahum Freidovitch, the grandfather, was a tough and strict businessman, but he was also a decent person. Felix's grandmother Tamma believed that the greatest good is hidden charity. From a very young age, she taught Felix that the only things truly ours are those given to others, the bread we cast upon the water.

One day, Janowa Puchalski came to the Freidovitches' house in labor, after her husband had smitten her in a drunken rage. She begged for her Jewish employer's help. Tamma Freidovitch did not hesitate for a second, she took care that Janowa will be treated in the Grodno Jewish Hospital, and after her convalescence even helped her with money. This hidden generosity was the beginning of a touching human story. By choosing to help Janowa, Tamma Freidovitch cast her bread upon the water, an act which was to save her grandson's life after many days.

As a child, Felix studied in Tarbut (Culture) Gymnasium in Grodno, where instruction was in Hebrew. From a very early age, Felix – who loved mathematics – dreamt of becoming an engineer. Like most Tarbut students, he also dreamt of immigrating to Palestine. In 1935, when he was eight, Poland was swept by a wave of pogroms. Organized Polish gangs attacked Jews and Grodno and destroyed Jewish property. In August 1939, the Ribbentrop-Molotov Pact was signed, which meant the obliteration of Poland and its division between the Nazis and the Soviets. Felix, who was by then 12 years old, realized that the outlook was grim, and that his life was about to change. Jews were being humiliated, beaten, and murdered in the streets. War was imminent, but almost nobody thought total destruction was just around the corner.

It didn't take long before Grodno was occupied by German troops. Jews had to wear a yellow armband, walk in the middle of the road and take their hat off when passing by German soldiers. From this point on, Felix Zandman's life became a hopeless battle for survival. His broad family took several steps to protect family members against the dreadful future awaiting them. They sew coins and banknotes into the clothes of each child and decided to find a hiding place for the family's possessions. Felix's uncle Sender suggested a brilliant solution: to build an extra wall in the cellar, one meter away from the existing one, where inside to hide the family's valuables.

As 1941 drew to a close, the Germans ordered all Grodno Jews into ghettos. Felix and his family moved with a relative who lived in an area called Ghetto No. 1. It was terribly overcrowded. Near the end of 1942, it was rumored that the Germans were about to liquidate the ghetto. Consequently, Felix's mother decided to take both her children and flee the ghetto. His father Aaron refused to leave his aging parents behind and chose to stay with them in the ghetto. The mother and her two children hid for several days in a hideout in the old family house outside the ghetto, but the Germans discovered them and they had to escape to the cellar, in its false wall the family belongings had been hidden during the beginning of the war. In the meantime, apparently, someone had broken a hole in the outer wall and stole everything. Although the valuables were missing, the hole in the wall remained, and through it, the three escaped with their lives.

Exhausted and remorseful, Felix's mother decided to return to the ghetto. Prospects outside were dim, and eventually, Felix had to return to the ghetto. Every day he went out to labor for the Germans, and his reward was to return home with a loaf of bread. In December 1942, the Germans moved several thousands of Jews from the Grodno Ghetto to the Kelbsin Camp. The Zandmans were taken, together with many others, to the town's central synagogue, where many of them were shot to death. From the synagogue, Felix, his parents, and his sisters were taken to Kelbsin – one station away from death. The food rations in the camp were meager, basically one portion of watery soup per day. Felix realized he had been sentenced to die, and decided to escape, despite the great danger involved. He hid in a wagon which left the camp, and then jumped off it. It took all his remaining strength to return to the Grodno Ghetto, where several of his family members still lived.

A little while later, all Kelbsin inmates were evacuated to the extermination camps, but Felix's parents and his sister Mira were spared and managed to return to the rest of the family in the Grodno Ghetto. Two weeks later, in the middle of January 1943, the Germans undertook a large-scale deportation operation in the ghetto. The expanded family decided to split and to hide in two hideouts, rather than willingly evacuate themselves. Eight of the younger family members, among them Felix and his aunt Fanya, hid in the kitchen attic. It was believed they would have the best chances of survival there. The rest of the family hid behind a partition wall in another, larger attic.

Two little babies were at home with the family, together with another baby of acquaintances. Because they feared the babies' crying would give the whole family away, Felix Zandman's grandfather made a courageous decision. The implacable businessman Nahum Freidovitch gave up his hiding place and remained at home with the three babies, two of whom were his grandchildren.

After two days in hiding, Fanya was verging on insanity because she missed her little boy Haim, who had remained with the grandfather. Felix, who couldn't stand her crying any longer, slid down from the attic to see how his family members were doing. But the grandfather and the babies were no longer there. They were taken to the death train, the three infants carried by the elderly Nahum. Felix tried to climb up the slippery trough and return to the attic, but to no avail. He had to give up and return to the other hideout, which was considered less safe. As luck would have it, all those hidden in the supposedly safer hideout got caught, while the others were not.

On February 12, 1943, the Nazis finally liquidated the Jewish ghetto at Grodno. At that time, Felix Zandman was working as a forced laborer outside the ghetto. He decided to escape to the last haven he could think of – his family's summer residence, where Jan and Janowa Puchalski were living with their five children. Terrorized, he implored Janowa to hide in her house for just one night, but she insisted on hiding him in the house for as long as it was necessary. A little while later, Felix's uncle Sender arrived also, together with a Jewish couple who also fled the ghetto. Sender, who was an engineer, had everyone dig a pit to be used as a hiding place. The pit was five foot long, four food wide and two feet deep. Inside this stifling tomb, under the Puchalskis' bedroom, the four Jews were crammed together – fifteen year-old Felix, his uncle Sender and Motl and Golda Bass. Janowa and her family had to stay alert, because it was rumored that the Puchalskis were hiding Jews. When a German arrived at the place with a dog to check it out, Janowa kept her cool. She spread black pepper around the pit, and the German and his dog left empty handed. Felix stayed in the pit for 17 whole months, with no books or notebooks, but with a strong urge to survive and remain sane. It was there that Sender taught him the basics of math and physics – all by heart.

The Road to Freedom

In July 1944, a mighty battle raged around the River Niemen, north of Grodno. The Red Army eventually took over the river's southern bank, pushing some 100,000 Wehrmacht troops towards central Poland. Four Jews were still hidden in the pit underneath the Puchalskis' house. The retreating troops ordered the Poles to evacuate the house, leaving their hidden guests without food. They had no choice but to forage at night for food, with Germans all around them. After walking a few yards, they got caught. They told the Germans that they were escaping the Bolsheviks on foot, and that they had been marching from the forest. The Germans were convinced and let them go.

When the war ended, Felix Zandman was a broken man, both physically and mentally. He went back to Janowa Puchalski, who treated him like a mother, feeding him and helping him return to his strength. In the aftermath of the war, Felix found out that he had lost almost all his family in the Holocaust. Of all Tamma and Nahum Freidovitch's grandchildren, he was the only one alive. In a book co-authored by Felix Zandman and journalist David Chanoff – Never the Last Journey – Felix described his struggle for survival.

Felix's uncle Sender, the only surviving member of his family, was both a father and a mother to him. After the war he took the high-school final exams in Poland and passed them successfully. Having both realized that their homeland had become a gigantic Jewish graveyard, Sander and his nephew decided to emigrate. They went to Paris, and felt free at last. In France, Felix studied physics and mechanical engineering at the University of Nancy, and later received a PhD cum laude in Physics from the Sorbonne.

Felix Zandman heard about photoelasticity for the first time in Nancy. This phenomenon had been discovered by Sir David Brewster in the 19^th century: when pressure is applied to glass which is later observed through polarizing filters, a variety of colors may be seen. Based on this observation and using mathematical formula, the stress on the glass at each point may be determined. Later on it was discovered that other transparent materials, such as plastics, behave similarly – applying pressure to plastic also produces an array of colors when observed through polarizing filters.

Photoelasticity captured Felix's heart. In the manufacturing industry, it is critical to know when and how a structure is about to break and how much force is required for that, in order to prevent engineering disasters. Felix came up with the brilliant idea of taking advantage of photoelasticity to measure stress in mechanical structures. The idea was to bond transparent plastic to the metal, or to coat the metal with it. The thin plastic coating will expand, shrink or bend just like the metal to which it is attached, and become twisted just like the metal surface, enabling it to reflect the changes in the metal.

Part of this research was included in Felix's doctoral dissertation. Since he couldn't find plastic materials to meet his precise requirements, he began developing them himself. Moreover, he had to develop the appropriate measuring devices and the mathematics behind his system. In time, Felix realized that in fact, he wasn't developing a single invention, but a whole new technology, to which he gave the trade name PhotoStress.

In order to assess the effectiveness of his new method, Dr. Zandman began a field study. He used to go to a bridge, attach transparent plastic to key points on its surface, have trucks cross the bridge and test the changes in the metal foundations. His results were compared to other methods, and proved perfectly reliable. After completing his doctoral studies, he began working for Snecma, a French government company which designed and produced airplane engines for the French Air Force. There, the young engineer could test stresses on planes during flight, focusing on the area there the wing is connected to the fuselage. Dr. Zandman coated the metal with a transparent plastic material, and discovered that when pressure is applied to the coated body, the plastic coating shows – using dedicated optical devices – shapes and colors reflecting the metal's weak points. This allowed him to identify particularly sensitive areas requiring redesign, as well as parts which needed regular replacement. Dr. Zandman patented this invention. It had immediate applications in the airplane and automobile industries, and the French government awarded him a medal for it.

The 1950's were an era of prosperity for American industry. American manufacturers sought experienced European scientists and engineers. In 1956, Zandman arrived in the United States, with only thirty English words he had memorized by heart. There he met his cousin Alfred Slaner for the first time. The two of them quickly befriended, and Alfred and his family made Felix feel completely at home in the new country. Alfred was later to become Felix's business partner.

The Budd conglomerate from Philadelphia was among those interested in the PhotoStress methodology. Budd produced a wide range of products, from railroad cars to automobile chassis. One of its divisions was Tatnall Measuring Systems, named after its founder, Frank Tatnall. This division produced electronic measurement devices. They developed strain gauges designed to measure the material deformation under stress, and were looking for new ideas. The Strain Gauge Department was headed by a brilliant physicist called Jim Star.

Soon enough, Dr. Zandman found himself invited to lectures all over the United States. Hundreds awaited him everywhere. Giants like General Motors, Chrysler and Boeing sought his advice. The PhotoStress method was quickly adopted in the automobile and airplane industries. Budd had him solve problems in special and secret projects. In the late 50's, for instance, Zandman consulted on an experimental General Electric project to produce a nuclear-powered airplane which was designed to fly for years without refueling, a project eventually abandoned due to technical difficulties.

Early on, many leading mechanics researchers doubted the viability of PhotoStress. Some of them had spent years developing mathematical models for photoelastic phenomena, and simply refused to accept the fact that their problems could be resolved by a simple, practical and easily available solution. However, thanks to the help of Professor Dan Post of the Worcester Polytechnic Institute in Massachusetts, Zandman succeeded in demonstrated to the academic world that his method is indeed effective and that it produces accurate results.

Founding the Vishay Factory

A resistor is a conducting component in an electric circuit which resists the passage of electric current through it, while converting electric to heat energy. This property is called electric resistance. Electric resistance may be seen as the electric equivalent of mechanic friction, since it involves an irreversible loss of energy. It is measured in Ohm units and denoted R. In every practical electric circuit, voltage has to be adjusted, distributed in different values or limited according to the requirements of the different electric devices served by the current. In a television set, for example, the video and audio receivers each require different voltage. Resistors are used for this purpose. The resistor reduces electric current just as a water tap limits water flow: the higher the resistance – the weaker the electric power.

One of the most common problems with resistors is sensitivity to temperature fluctuations. These affect the resistors' resistance, and consequently the voltage distribution to the various electric components. In electric circuits designed for high-quality precise applications, such as aerospace devices, such changes may have critical consequences. The lower the resistor's sensitivity to temperature fluctuations, the airplane, for example, will perform better with fewer malfunctions.

The old electronic appliances of the late fifties and early sixties used to heat up considerably, causing frequent malfunctions. The electronic industry was looking for a solution. In 1961, Felix Zandman came up with such a solution, considered a breakthrough in the history of electronics: a resistor combining metal with a ceramic material. Zandman invented the combined resistor while thinking of Lord Kelvin's idea from the 1860s. Kelvin had discovered that stretching a metallic conductor increases its resistance and vice versa. Since heating expands matter, heated conductors become more resistant. However, different materials expand at different rates. When heated, metals would expand more than ceramics. If a piece of metal is glued to a ceramic material, the metal will "seek" to expand more than the ceramic, but will be unable to, and therefore maintain its resistance level. Such a resistor enables the production of highly precise electronic equipment, which could be used also for jets and satellites, which normally undergo significant temperature fluctuations.

At that time Budd Company was in turmoil. Frank Tatnall, Felix's old pal, retired. Jim Star decided to follow him and resigned. It was then that Zandman decided that his primary ambition is to R&D the new resistor. Consequently, he left Budd in 1962, and thanks to a $20,000 loan from his cousin Alfred Slaner, he started the Vishay Company. Alfred entered Vishay as Felix's business partner. The company was named after the small town of Vishay, where Tamma Friedowitz and Jake Slaner – Alfred's father – were born.

With Jim Star and Dan Post appointed to the development team as technical partners, a prototype resistor was produced in six months. Its performance was excellent, but it looked odd. Until then, all resistors were cylindrical, while this one was flat since it was made of a ceramic surface on which the metal foil was glued. The cheapest and most appropriate material for gluing metal foils was simple glass. The so-called Foil Resistor proved a technological breakthrough and a commercial success – the American armed forces and NASA were among Vishay's first clients.

Miniaturization is one of the primary objectives of the electronics industry – nobody wants to walk around with a cellular phone the size of a suitcase… Accordingly, the question was how to miniaturize resistors? How to combine the resistance of resistor 2 with that of resistor 1 without doubling its size? Zandman came up with a brilliant solution for that problem during lunch. The original paper napkin with the idea's design is exhibited at the Smithsonian. Zandman suggested cutting the etal into pieces so that instead of moving straight, the current would move in curves. This brilliant idea is considered to be one of the most important inventions in 20th-century electronics since it enabled significant miniaturization of resistors.

The Thermal Sleeve and the Merkava Tank

In 1968, following De-Gaulle's embargo on weapons sales to Israel, the Israeli Aerospace Industries approached Zandman with the suggestion of founding a resistor factory in Israel. A devout Zionist, Zandman was only too happy to agree. He put his second cousin Moshe Shamir, who until then had managed the Sugat sugar factory, in charge of his businesses in Israel. The company was started in 1969, and today employs some 4,000 workers in factories throughout the country.

In 1971, Prime Minister Golda Meir sent general Israel Tal to a fundraising event in Philadelphia. At dinner, he met Felix Zandman and had a serious talk with him. At the time, general Tal, which was considered one of the greatest tank commanders in the IDF, spearheaded the Merkava Project designed to develop an original Israeli tank model and production line in response to the embargo.

One of the main problems in designing a tank cannon is the temperature difference between its upper part (exposed to the sun) and its lower, shaded part. This slightly deflects and bends the cannon turret, resulting in imprecise fire. When aiming at a thousand yards, the shell might miss by a yard. Until that time, the common and not-so-effective solution was partial thermal insulation of the cannon. Full insulation could cause overheating, which is dangerous when firing.

Zandman came up with the idea of a thermal sleeve, which conducts the heat from the cannon's upper part to its lower part. This is an excellent example of out-of-the-box thinking – instead of insulating the turret, it is made to act like a heat conductor. The thermal sleeve is mounted on the turret, enabling the heat from the sun to be distributed all over it. This significantly reduces the turret's deflection and increases its precision. This invention has already proven itself in the 1982 Lebanon War. Zandman donated his solution to the State of Israel.

Building an Empire

The year 1985 was a turning point in Felix Zandman's business career when Vishay acquired Nebraska-based Dale Electronics. Dale was considered a much bigger fish than Vishay at the time. This heralded a period of significant growth for Vishay. It acquired additional companies, such as the French Sfernice and the German Draloric Electronic. In 1991, it acquired Sprague Electric, which specialized in manufacturing multilayered tantalum capacitors. In 1992, Sandman took over the German Röderstein, then the largest manufacturer of electronic components in Europe. This made the Vishay conglomerate a global player in the resistor and capacitor area. In 1993, Vishay was included in the Fortune 500 list.

A particularly poetic victory was won by Zandman when he acquired Telefunken, the successor of prewar AEG. In 1881, Emil Rathenau bought the rights to manufacture products based on Thomas Edison's patents, and in 1883 he started the German electricity industry when he founded a company later (1887) renamed AEG. His eldest son Walther was appointed Germany's first and only Jewish Foreign Minister in 1922, but was assassinated that year by the extreme right. After the Nazis came to power, they nationalized AEG, which went on to play a central role in the German war effort. After the war, the renamed Telefunken became the jewel in the crown of German electronics. It was acquired by the Daimler-Benz conglomerate in 1985.

Due to economic difficulties and expected foreclosure, Daimler-Benz sold Telefunken to Vishay in 1998. Felix Zandman felt he was closing a circle. When the contract was being signed, Zandman put a yarmulke on his head and said a blessing. This was his greatest victory – former war industries owned by Vishay in Germany.

Today, Vishay manufactures a variety of electronic components and employs tens of thousands of workers in factories around the world, including the United States, France, Britain, Japan, Canada, Mexico, Germany, Singapore, the Czech Republic, Portugal, China and Israel. Vishay is one of the largest manufacturers of semiconductors and passive electronic components (resistors, capacitors, inductors sensors, and transducers). The company is traded at NYSE with a market value estimated at $3 billion.

• I thank Rafi Ashkenazi for his contribution and assistance.

• Dr. Dana Ashkenazi received her Ph.D. in Mechanical Engineering from Tel-Aviv University and her first and second degrees in Materials Science and Engineering from Ben-Gurion University. She conducts research in the field of Materials Science and Engineering and also has great interest in popular science, art and human culture.

• The article was first published in: Dana Ashkenazi. From Darkness to Photoelasticity. Galileo 105 (2007) (in Hebrew).

Further Reading

Felix Zandman and David Chanoff, Never the Last Journey, Schocken Books, Inc. (1995).

http://www.fundinguniverse.com/company-histories/vishay-intertechnology-inc-history