.jpg)
MOLD: PREVENTION AND CONTROL
Mold is a common occurrence in homes, but it can potentially cause health problems as well as damage to structures and surfaces if it is not controlled. Mold begins growing indoors when spores come in contact with wet surfaces or substances. Once established, mold can be very difficult to remove successfully – so prevention is the key.
MOLD PREVENTION
Mold cannot grow in the absence of moisture. Moisture can take the form of leaks, spills, condensation, and humidity, so controlling sources of moisture is the most important step in mold prevention. Here are some ways homeowners can avoid creating conditions in which mold will thrive:
• Be alert for signs of leaks in supply and waste lines for bathrooms, kitchens, utility sinks, and laundry areas. Have any leaks fixed and dry the area thoroughly.
• Check the condition of grout and tile on shower walls, floors, and around bathtubs. Repair damaged grout, and seal it to prevent mold from being absorbed.
• Increase ventilation to the outside by using exhaust fans, and be sure the attic is properly ventilated.
• Regularly empty and clean drain pans and hoses for air conditioning units and dehumidifiers.
• Check for roof leaks that allow water to enter attic spaces or build up under roof shingles. Even a small amount of moisture can cause big problems down the road.
• If possible, lower the overall humidity in the home to decrease condensation and create a less mold-friendly environment.
Places that tend to stay damp, such as showers, may be more difficult to keep entirely free of mold but it can be minimized. Diligent cleaning, opening a window or regularly using a ventilation fan are often enough to keep mold at bay.
MOLD REMOVAL
Once mold has become established in the home it can be difficult to eradicate. Depending on the location and severity of the mold problem, a homeowner may need to engage a professional certified in mold remediation to remove it. A qualified professional will also take preventive measures to lessen the likelihood of recurrences.
Article courtesy of Pillar To Post Professional Home Inspection
www.pillartopost.com
Thursday, February 23, 2012
Wednesday, February 22, 2012
Hertz and radio waves
Heinrich Rudolf Hertz
--------------------------------------------------------------------------------
Born: 22 Feb 1857 in Hamburg, Germany
Died: 1 Jan 1894 in Bonn, Germany
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to see two larger pictures
Show birthplace location
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Heinrich Hertz's parents were Gustav Ferdinand Hertz and Anna Elisabeth Pfefferkorn. Gustav Hertz was a Jew who converted to become a Lutheran. Anna, the daughter of a Frankfurt doctor, came from a Lutheran family, so Heinrich was brought up as a Lutheran. He was the oldest of his parents' five children, having three younger brothers and one younger sister. Gustav was a barrister in Hamburg, later moving to Oberlandsgerichtsrat, and finally in 1887 becoming a Senator. Let us note that one of Heinrich's brothers was named Gustav Hertz and he had a son, also named Gustav Hertz who also has a biography in this archive.
Heinrich's formal education began at the age of six when he was enrolled in a private school run by Richard Lange [1]:-
... a taskmaster who had no patience with error. [Heinrich's] mother watched closely over his lessons, determined that he should be - as he was - first in his class.
For ten years Hertz studied at Richard Lange's school. He showed a whole host of talents: he had considerable practical skills which he used in doing woodwork with tools he had been given, and later he used a lathe to make apparatus with which he carried out experiments. He also had great language skills, both with modern and classical languages. In 1872 he entered the Johanneum Gymnasium in Hamburg and there he continued to excel at a wide range of subjects. He even took additional subjects with a private tutor, such as Arabic and technical drawing, which were outside the range offered at the school. Not only was he good at many subjects but he also liked these topics and struggled to make decisions about which he should specialise in at university. Should he take engineering and use his practical skills, or should he study the natural sciences which he also loved? He took his Abitur examinations in the spring of 1875 and, having decided to make a career in engineering, he went to Frankfurt to gain practical experience. He had made the wrong decision.
Hertz spent the year 1875-76 in Frankfurt where he gained practical experience in the building industry and also studied for the state examinations in engineering. Already at this stage he began to feel that engineering might not be the right topic for him. He did not enjoy the work environment, he was too isolated and this he felt was due to working in the private sector. He was now struggling to come to terms with having made the wrong decision; should he waste the time spent on this false start and begin again or should he make to best of a bad job and persevere? He decided to continue to follow the engineering route, going to Dresden Polytechnic for a short while in 1876 before leaving to do military service for a year in Berlin. After completing this year in the railway regiment, he went to Munich with the intention of continuing his engineering course at the Technische Hochschule there. That he was on the wrong road was by now so clear to him. There were several new factors in the equation which affected the issue such as, on the negative side, his unhappiness with the working environment of engineering firms, and on the positive side, his enjoyment of the mathematics he had learnt as part of his engineering studies. Hertz's father was supplying the financial support to allow him to undertake higher education so if he were to change direction he would certainly need his father's approval. He explained his soul searching problems to his father and asked if he would continue to support him if he entered the University of Munich and aimed at a research career. McCormmach writes [1]:-
To him engineering meant business, data, formulas - an ordinary life on a par with bookbinding or wood working - and he was uninterested. Although the Technische Hochschule had a good physics laboratory, a course of study there led to state examinations and usually a practical career. The university by contrast promised a life of never-ending study and research, one that suited Hertz's scholarly, idealistic tastes; he knew above all he wanted to be a great investigator.
The arguments convinced his father that he should support his son's change of direction. Hertz matriculated at the University of Munich in 1877 and spent the first semester gaining the necessary background in mathematics. He was advised by von Jolly to read works of Lagrange, Laplace and Poisson [1]:-
Although Hertz thought that, when properly grasped, everything in nature is mathematical, he was in his student days - as throughout his career - interested primarily in physical and only indirectly in mathematical problems.
He took courses on physics, zoology and astronomy as well as on mathematics taking courses in the second semester both at the University and at the Technische Hochschule. After a year at Munich he moved to Berlin, not due to any unhappiness with what he was now doing but rather because it was the standard practice at the time for German students to move between institutions. At Berlin he studied under Helmholtz and Kirchhoff. Immediately, despite only one year of university study behind him, Hertz wanted to start research. A prize had been announced by the Philosophy Faculty for the solution of an experimental problem concerning electrical inertia and Hertz was very keen to enter. The prize had been proposed by Helmholtz and, despite Hertz's lack of experience, he realised his great potential and offered Hertz a room in his Physical Institute and considerable support in directing Hertz to the background literature.
Now Hertz knew he was on the right road [1]:-
He wrote home that his great satisfaction lay in seeking and communicating new truths about nature. Occupied any other way he felt a useless member of society; private study as opposed to research seemed selfish and indulgent.
He was awarded the Philosophy Faculty prize and gold medal in 1879. Helmholtz now suggested that Hertz work on the prize topic proposed by him for the Berlin Academy of Sciences. This asked for experimental evidence for or against the assumptions that underlied Maxwell's theory. This sounded interesting to Hertz yet wanted to progress rapidly in his chosen area and felt that he could not embark on a project likely to take around three years. He declined to follow Helmholtz's proposal, and instead wrote a theoretical work Über die Induction in rotirenden Kugeln on electromagnetic induction and submitted it for his doctorate in January 1880; it had only taken him three months to complete. Hertz's work on the electromagnetic fields associated with a circular disk turning about its axis of symmetry in a magnetic field parallel to the axis of the disk is considered in [7]. He took the necessary oral examination in the following month and was awarded his doctorate with distinction by the University of Berlin. He was then employed as an assistant to Helmholtz at the Berlin Physical Institute.
During the three years 1880-83 that Hertz worked at the Berlin Physical Institute, he wrote fifteen papers on a variety of topics. Most related to electricity, two were on cathode rays, and several were on instruments such as a new ammeter and new hygrometer. Hertz had to decide on the best way to progress his career. He was already in the best place to undertake research in physics and working with Helmholtz who, Hertz felt, was the best physicist in the world. However to become a privatdozent in Berlin would put him in competition with a large number of scientists who were already in privatdozent positions there. He made a decision to try to take advantage of the expansion of mathematical physics throughout German universities and, although his real love was in experimenting, to seek a privatdozent position in mathematical physics. The University of Kiel was seeking someone in exactly that area so, with strong recommendations from Helmholtz, he habilitated in Kiel.
It was in Kiel that Hertz first showed his strength as a lecturer. He had deliberately taken a position in mathematical physics at a university which had no physical laboratories fitted out for research. As a consequence he undertook theoretical work, writing three papers during the two years he worked there. One paper was on meteorology, one was on electric and magnetic units, while the third was the most important since it represented his first work on Maxwell's theories. After two years he was keen to return to an institution with a strong experimental reputation and the offer of an extraordinary professorship in the Technische Hochschule in Karlsruhe seemed ideal. He accepted the position and gave his inaugural lecture On the energy balance of the Earth on 20 April 1885. (See [24] where the lecture is published for the first time.) The Technische Hochschule in Karlsruhe is today the Universität Karlsruhe, and it was here that Hertz made his most important discovery, the one with which his name is mostly associated, namely his famous discovery of long-wavelength electromagnetic waves in 1888. However, when he first took up the post it was far from clear that he was on the verge of greatness [1]:-
His stay began inauspiciously; for a time he was lonely and uncertain about what research to begin next.
He was then distracted from research for the first time since he first arrived in Berlin in 1878. He met Elizabeth Doll, the daughter of one of his colleagues, soon after arriving in Karlsruhe and they married in July 1886; they had two daughters, Johanna and Mathilde. It was in November 1886 that he began work on the problem which Helmholtz had posed for the Berlin Academy of Sciences and had tried to persuade him to become involved with back in 1879. However, it may have been a wise decision to delay beginning the work as S D'Agostino [11] suggests that Hertz's derivation of Maxwell's equations in 1884 formed an important part of the structural background to his studies on the propagation of electric waves which he now carried out. Doncel examines Hertz's thinking in [14]. He writes:-
This paper provides new elements for reconstructing Heinrich Hertz's conversion from an electrodynamic concept to a concept of field theory, a process that took place between September 1887 and February 1888. ... It is concluded that Hertz's idea of 'air waves' belongs at the very end of this process, and was mainly attained through experimental hints found within Helmholtz's theoretical framework.
Now Hertz saw his discovery as merely a step towards a deeper understanding of Maxwell's theory. He certainly did not foresee the incredible applications which, after Marconi read Hertz's paper and saw its practical application, would transform communication and entertainment. Hertz wrote:-
I do not think that the wireless waves I have discovered will have any practical application.
D'Agostino in [13] adds more to understanding Hertz's research in electromagnetic theory and his development of Maxwell's experiments. Hertz needed new apparatus to prove Maxwell's theory of the existence of electromagnetic waves and he worked his way towards this which was finally achieved in 1888. During four years in Karlsruhe Hertz published nine papers. His fame was now considerable and he was approached by the University of Giessen with a persuasive offer. However he was also asked to go to Berlin as a replacement for Kirchhoff. As always, Hertz thought deeply about the consequences of accepting the positions. Berlin, he mused, would mean a position of high responsibility, considerable administrative duties, and little time for research. He felt that this would be a good research move later in his career, but he was only 31 years old and he wanted to devote most of his time to research. Helmholtz told Hertz that he would make sure he had a top quality laboratory in Berlin but still Hertz did not feel it was the right move. Then he received an offer of an ordinary professorship at the University of Bonn in December 1888 [1]:-
He gladly accepted, more for Bonn's beautiful and quiet setting on the Rhine than for its scientific prospects.
The vacancy at Bonn came about because Rudolf Clausius had died in August 1888. When Hertz moved to Bonn in the spring of 1889 not only did he move into Clausius' chair but he also moved into his house. He undertook more research into Maxwell's theories, publishing two theoretical papers in 1890. He searched for a mechanical basis for electrodynamics starting from Maxwell's equations. As he wrote in the Introduction to Electric waves (an English translation of some of his papers published in 1893):-
Maxwell's theory is Maxwell's system of equations.
Hertz was a fervent believer in the aether and during this work proposed identifying electromagnetic fields in free space with polarization of the aether. McCormmach writes [1]:-
Hertz brought an unparalleled clarity to Maxwell's theory, organising its concepts and its formalism so that others were able quickly to go beyond him.
Even before moving to Bonn, Hertz suffered the first signs of his serious health problems. He had already complained of toothache and had major dental treatment. In 1889 he had all his teeth removed in an attempt to cure the persistent condition. However, by early 1892 the problem returned, this time in his throat and nose. The pain became to intense that he could no longer work. He was given hay fever treatment and went to health clinics to try to find a cure. Nothing was successful, and this was not too surprising since the condition was caused by a malignant bone condition. Bravely he began teaching again in the spring of 1893, undergoing several operations which at least provided a short spell of respite but one consequence of the illness was that he now suffered from depression. He began his 1893-94 lecture courses in the autumn of 1893 and on 3 December he sent the manuscript of his book Die Prinzipien der Mechanik to the publisher. He gave his final lecture on 7 December. He died less than a month later.
In mechanics Hertz followed Kirchhoff and considered only length, time and mass as the fundamental entities, force being a derived concept. In Die Prinzipien der Mechanik (Principles of mechanics) Hertz hoped to explain all electromagnetic phenomena, in terms of a mechanical aether [1]:-
Hertz explained in the Introduction to the 'Principles' that to construct a mechanics capable of accounting for the lawful interaction of perceptible bodies it was necessary to add a hypothesis to the three concepts [length, time and mass]. The hypothesis was that in addition to perceptible masses the universe contained hidden, moving masses bound to one another by rigid constraints.
In [18] Lützen discusses Hertz's introduction of hidden mass. In [19] he talks about Hertz's approach to mechanics having three novelties: (1) a philosophical introduction, (2) an account of mechanics that does not introduce force as a basic concept, and (3) a geometric form. In fact in [26] Tougas claims that the philosophical introduction to Die Prinzipien der Mechanik strongly influenced Wittgenstein's Tractatus logico-philosophicus. (See also Barker [6]. Hamilton [15] and Kjaergaard [17] where Hertz's philosophy is discussed.) Another interesting approach to the same question is by Wilson in [27]. He writes:-
During the past decade and a half, several scholars have tried to gain a better understanding of Wittgenstein's early thought by examining the philosophical aspects of his scientific education. Those taking this historical approach have focused almost exclusively on the connection between Wittgenstein's picture theory of linguistic meaning and the epistemology of mental pictures developed by the physicist Heinrich Hertz in the introduction to his Die Prinzipien der Mechanik, published in 1894. They have taken their cue, quite naturally, from Wittgenstein, who refers twice to Hertz's work in the Tractatus logico-philosophicus. In addition to Hertz, but to a much lesser extent, they have also discussed the role played by Ludwig Boltzmann's philosophical writings in Wittgenstein's intellectual development. ... While analysing and stressing the importance of Hertz's influence on Wittgenstein, however, they have misconstrued the chronological and substantive relationship between Hertz's philosophy and the philosophical writings and ideas of Boltzmann. This, in turn, has significantly affected the current understanding of the genesis and development of Wittgenstein's early thought.
An English translation of Die Prinzipien der Mechanik was published in 1899, and reprinted by Dover Publications in 1956.
After Hertz died, one of his friends gave this eulogy:-
He was a noble man, who had the singular good fortune to find many admirers, but none to hate or envy him; those who came into personal contact with him were struck by his modesty and charmed by his amiability. He was a true friend to his friends, a respected teacher to his students, who had begun to gather around him in large numbers, some of the coming from great distances; and to his family a loving husband and father.
Article by: J J O'Connor and E F Robertson
--------------------------------------------------------------------------------
Born: 22 Feb 1857 in Hamburg, Germany
Died: 1 Jan 1894 in Bonn, Germany
Click the picture above
to see two larger pictures
Show birthplace location
Previous (Chronologically) Next Main Index
Previous (Alphabetically) Next Biographies index
Version for printing
--------------------------------------------------------------------------------
Heinrich Hertz's parents were Gustav Ferdinand Hertz and Anna Elisabeth Pfefferkorn. Gustav Hertz was a Jew who converted to become a Lutheran. Anna, the daughter of a Frankfurt doctor, came from a Lutheran family, so Heinrich was brought up as a Lutheran. He was the oldest of his parents' five children, having three younger brothers and one younger sister. Gustav was a barrister in Hamburg, later moving to Oberlandsgerichtsrat, and finally in 1887 becoming a Senator. Let us note that one of Heinrich's brothers was named Gustav Hertz and he had a son, also named Gustav Hertz who also has a biography in this archive.
Heinrich's formal education began at the age of six when he was enrolled in a private school run by Richard Lange [1]:-
... a taskmaster who had no patience with error. [Heinrich's] mother watched closely over his lessons, determined that he should be - as he was - first in his class.
For ten years Hertz studied at Richard Lange's school. He showed a whole host of talents: he had considerable practical skills which he used in doing woodwork with tools he had been given, and later he used a lathe to make apparatus with which he carried out experiments. He also had great language skills, both with modern and classical languages. In 1872 he entered the Johanneum Gymnasium in Hamburg and there he continued to excel at a wide range of subjects. He even took additional subjects with a private tutor, such as Arabic and technical drawing, which were outside the range offered at the school. Not only was he good at many subjects but he also liked these topics and struggled to make decisions about which he should specialise in at university. Should he take engineering and use his practical skills, or should he study the natural sciences which he also loved? He took his Abitur examinations in the spring of 1875 and, having decided to make a career in engineering, he went to Frankfurt to gain practical experience. He had made the wrong decision.
Hertz spent the year 1875-76 in Frankfurt where he gained practical experience in the building industry and also studied for the state examinations in engineering. Already at this stage he began to feel that engineering might not be the right topic for him. He did not enjoy the work environment, he was too isolated and this he felt was due to working in the private sector. He was now struggling to come to terms with having made the wrong decision; should he waste the time spent on this false start and begin again or should he make to best of a bad job and persevere? He decided to continue to follow the engineering route, going to Dresden Polytechnic for a short while in 1876 before leaving to do military service for a year in Berlin. After completing this year in the railway regiment, he went to Munich with the intention of continuing his engineering course at the Technische Hochschule there. That he was on the wrong road was by now so clear to him. There were several new factors in the equation which affected the issue such as, on the negative side, his unhappiness with the working environment of engineering firms, and on the positive side, his enjoyment of the mathematics he had learnt as part of his engineering studies. Hertz's father was supplying the financial support to allow him to undertake higher education so if he were to change direction he would certainly need his father's approval. He explained his soul searching problems to his father and asked if he would continue to support him if he entered the University of Munich and aimed at a research career. McCormmach writes [1]:-
To him engineering meant business, data, formulas - an ordinary life on a par with bookbinding or wood working - and he was uninterested. Although the Technische Hochschule had a good physics laboratory, a course of study there led to state examinations and usually a practical career. The university by contrast promised a life of never-ending study and research, one that suited Hertz's scholarly, idealistic tastes; he knew above all he wanted to be a great investigator.
The arguments convinced his father that he should support his son's change of direction. Hertz matriculated at the University of Munich in 1877 and spent the first semester gaining the necessary background in mathematics. He was advised by von Jolly to read works of Lagrange, Laplace and Poisson [1]:-
Although Hertz thought that, when properly grasped, everything in nature is mathematical, he was in his student days - as throughout his career - interested primarily in physical and only indirectly in mathematical problems.
He took courses on physics, zoology and astronomy as well as on mathematics taking courses in the second semester both at the University and at the Technische Hochschule. After a year at Munich he moved to Berlin, not due to any unhappiness with what he was now doing but rather because it was the standard practice at the time for German students to move between institutions. At Berlin he studied under Helmholtz and Kirchhoff. Immediately, despite only one year of university study behind him, Hertz wanted to start research. A prize had been announced by the Philosophy Faculty for the solution of an experimental problem concerning electrical inertia and Hertz was very keen to enter. The prize had been proposed by Helmholtz and, despite Hertz's lack of experience, he realised his great potential and offered Hertz a room in his Physical Institute and considerable support in directing Hertz to the background literature.
Now Hertz knew he was on the right road [1]:-
He wrote home that his great satisfaction lay in seeking and communicating new truths about nature. Occupied any other way he felt a useless member of society; private study as opposed to research seemed selfish and indulgent.
He was awarded the Philosophy Faculty prize and gold medal in 1879. Helmholtz now suggested that Hertz work on the prize topic proposed by him for the Berlin Academy of Sciences. This asked for experimental evidence for or against the assumptions that underlied Maxwell's theory. This sounded interesting to Hertz yet wanted to progress rapidly in his chosen area and felt that he could not embark on a project likely to take around three years. He declined to follow Helmholtz's proposal, and instead wrote a theoretical work Über die Induction in rotirenden Kugeln on electromagnetic induction and submitted it for his doctorate in January 1880; it had only taken him three months to complete. Hertz's work on the electromagnetic fields associated with a circular disk turning about its axis of symmetry in a magnetic field parallel to the axis of the disk is considered in [7]. He took the necessary oral examination in the following month and was awarded his doctorate with distinction by the University of Berlin. He was then employed as an assistant to Helmholtz at the Berlin Physical Institute.
During the three years 1880-83 that Hertz worked at the Berlin Physical Institute, he wrote fifteen papers on a variety of topics. Most related to electricity, two were on cathode rays, and several were on instruments such as a new ammeter and new hygrometer. Hertz had to decide on the best way to progress his career. He was already in the best place to undertake research in physics and working with Helmholtz who, Hertz felt, was the best physicist in the world. However to become a privatdozent in Berlin would put him in competition with a large number of scientists who were already in privatdozent positions there. He made a decision to try to take advantage of the expansion of mathematical physics throughout German universities and, although his real love was in experimenting, to seek a privatdozent position in mathematical physics. The University of Kiel was seeking someone in exactly that area so, with strong recommendations from Helmholtz, he habilitated in Kiel.
It was in Kiel that Hertz first showed his strength as a lecturer. He had deliberately taken a position in mathematical physics at a university which had no physical laboratories fitted out for research. As a consequence he undertook theoretical work, writing three papers during the two years he worked there. One paper was on meteorology, one was on electric and magnetic units, while the third was the most important since it represented his first work on Maxwell's theories. After two years he was keen to return to an institution with a strong experimental reputation and the offer of an extraordinary professorship in the Technische Hochschule in Karlsruhe seemed ideal. He accepted the position and gave his inaugural lecture On the energy balance of the Earth on 20 April 1885. (See [24] where the lecture is published for the first time.) The Technische Hochschule in Karlsruhe is today the Universität Karlsruhe, and it was here that Hertz made his most important discovery, the one with which his name is mostly associated, namely his famous discovery of long-wavelength electromagnetic waves in 1888. However, when he first took up the post it was far from clear that he was on the verge of greatness [1]:-
His stay began inauspiciously; for a time he was lonely and uncertain about what research to begin next.
He was then distracted from research for the first time since he first arrived in Berlin in 1878. He met Elizabeth Doll, the daughter of one of his colleagues, soon after arriving in Karlsruhe and they married in July 1886; they had two daughters, Johanna and Mathilde. It was in November 1886 that he began work on the problem which Helmholtz had posed for the Berlin Academy of Sciences and had tried to persuade him to become involved with back in 1879. However, it may have been a wise decision to delay beginning the work as S D'Agostino [11] suggests that Hertz's derivation of Maxwell's equations in 1884 formed an important part of the structural background to his studies on the propagation of electric waves which he now carried out. Doncel examines Hertz's thinking in [14]. He writes:-
This paper provides new elements for reconstructing Heinrich Hertz's conversion from an electrodynamic concept to a concept of field theory, a process that took place between September 1887 and February 1888. ... It is concluded that Hertz's idea of 'air waves' belongs at the very end of this process, and was mainly attained through experimental hints found within Helmholtz's theoretical framework.
Now Hertz saw his discovery as merely a step towards a deeper understanding of Maxwell's theory. He certainly did not foresee the incredible applications which, after Marconi read Hertz's paper and saw its practical application, would transform communication and entertainment. Hertz wrote:-
I do not think that the wireless waves I have discovered will have any practical application.
D'Agostino in [13] adds more to understanding Hertz's research in electromagnetic theory and his development of Maxwell's experiments. Hertz needed new apparatus to prove Maxwell's theory of the existence of electromagnetic waves and he worked his way towards this which was finally achieved in 1888. During four years in Karlsruhe Hertz published nine papers. His fame was now considerable and he was approached by the University of Giessen with a persuasive offer. However he was also asked to go to Berlin as a replacement for Kirchhoff. As always, Hertz thought deeply about the consequences of accepting the positions. Berlin, he mused, would mean a position of high responsibility, considerable administrative duties, and little time for research. He felt that this would be a good research move later in his career, but he was only 31 years old and he wanted to devote most of his time to research. Helmholtz told Hertz that he would make sure he had a top quality laboratory in Berlin but still Hertz did not feel it was the right move. Then he received an offer of an ordinary professorship at the University of Bonn in December 1888 [1]:-
He gladly accepted, more for Bonn's beautiful and quiet setting on the Rhine than for its scientific prospects.
The vacancy at Bonn came about because Rudolf Clausius had died in August 1888. When Hertz moved to Bonn in the spring of 1889 not only did he move into Clausius' chair but he also moved into his house. He undertook more research into Maxwell's theories, publishing two theoretical papers in 1890. He searched for a mechanical basis for electrodynamics starting from Maxwell's equations. As he wrote in the Introduction to Electric waves (an English translation of some of his papers published in 1893):-
Maxwell's theory is Maxwell's system of equations.
Hertz was a fervent believer in the aether and during this work proposed identifying electromagnetic fields in free space with polarization of the aether. McCormmach writes [1]:-
Hertz brought an unparalleled clarity to Maxwell's theory, organising its concepts and its formalism so that others were able quickly to go beyond him.
Even before moving to Bonn, Hertz suffered the first signs of his serious health problems. He had already complained of toothache and had major dental treatment. In 1889 he had all his teeth removed in an attempt to cure the persistent condition. However, by early 1892 the problem returned, this time in his throat and nose. The pain became to intense that he could no longer work. He was given hay fever treatment and went to health clinics to try to find a cure. Nothing was successful, and this was not too surprising since the condition was caused by a malignant bone condition. Bravely he began teaching again in the spring of 1893, undergoing several operations which at least provided a short spell of respite but one consequence of the illness was that he now suffered from depression. He began his 1893-94 lecture courses in the autumn of 1893 and on 3 December he sent the manuscript of his book Die Prinzipien der Mechanik to the publisher. He gave his final lecture on 7 December. He died less than a month later.
In mechanics Hertz followed Kirchhoff and considered only length, time and mass as the fundamental entities, force being a derived concept. In Die Prinzipien der Mechanik (Principles of mechanics) Hertz hoped to explain all electromagnetic phenomena, in terms of a mechanical aether [1]:-
Hertz explained in the Introduction to the 'Principles' that to construct a mechanics capable of accounting for the lawful interaction of perceptible bodies it was necessary to add a hypothesis to the three concepts [length, time and mass]. The hypothesis was that in addition to perceptible masses the universe contained hidden, moving masses bound to one another by rigid constraints.
In [18] Lützen discusses Hertz's introduction of hidden mass. In [19] he talks about Hertz's approach to mechanics having three novelties: (1) a philosophical introduction, (2) an account of mechanics that does not introduce force as a basic concept, and (3) a geometric form. In fact in [26] Tougas claims that the philosophical introduction to Die Prinzipien der Mechanik strongly influenced Wittgenstein's Tractatus logico-philosophicus. (See also Barker [6]. Hamilton [15] and Kjaergaard [17] where Hertz's philosophy is discussed.) Another interesting approach to the same question is by Wilson in [27]. He writes:-
During the past decade and a half, several scholars have tried to gain a better understanding of Wittgenstein's early thought by examining the philosophical aspects of his scientific education. Those taking this historical approach have focused almost exclusively on the connection between Wittgenstein's picture theory of linguistic meaning and the epistemology of mental pictures developed by the physicist Heinrich Hertz in the introduction to his Die Prinzipien der Mechanik, published in 1894. They have taken their cue, quite naturally, from Wittgenstein, who refers twice to Hertz's work in the Tractatus logico-philosophicus. In addition to Hertz, but to a much lesser extent, they have also discussed the role played by Ludwig Boltzmann's philosophical writings in Wittgenstein's intellectual development. ... While analysing and stressing the importance of Hertz's influence on Wittgenstein, however, they have misconstrued the chronological and substantive relationship between Hertz's philosophy and the philosophical writings and ideas of Boltzmann. This, in turn, has significantly affected the current understanding of the genesis and development of Wittgenstein's early thought.
An English translation of Die Prinzipien der Mechanik was published in 1899, and reprinted by Dover Publications in 1956.
After Hertz died, one of his friends gave this eulogy:-
He was a noble man, who had the singular good fortune to find many admirers, but none to hate or envy him; those who came into personal contact with him were struck by his modesty and charmed by his amiability. He was a true friend to his friends, a respected teacher to his students, who had begun to gather around him in large numbers, some of the coming from great distances; and to his family a loving husband and father.
Article by: J J O'Connor and E F Robertson
Wednesday, February 15, 2012
Practical Advice for New Homeowners
Home News Thanks to Tim Higgins 2010 -thiggins@embracehomeloans.com
Practical Advice for New Homeowners
There's nothing more exciting than opening the door to your first new home and knowing that it's actually yours, that you actually own it! No landlord bothering you about every little thing. No silly rules about what colors you can paint or what renovations you want to make. Finally you can do whatever you want to do in your home!
And while this is a great feeling, and the pride you feel is natural and well deserved, don't allow yourself to get too carried away with your newfound freedom. You worked hard to earn this opportunity and you don't want to potentially jeopardize your investment by letting your emotions get the better of you.
If you've recently bought your first home or you plan to do so soon, take a few moments to think about the practical side of home ownership before you start making any major changes or renovations. Doing this will help ensure that your first home becomes the personalized place you always wanted and worked so hard to get.
Get properly insured – Before you decide to build or tear down anything, be sure that you are properly insured. Even if you enjoyed the full $8,000 tax credit for first-time home buyers (or the full $6,500 tax credit now available to qualified "repeat" buyers), sit down with your insurance provider and make sure you're covered on all fronts before you do anything. It doesn't make sense to spend your tax money upgrading your home if you're not protected in advance.
Maintenance before makeover – It's true that you no longer have a landlord looking over your shoulder for every little thing. But, you also don't have a landlord to turn to if something should go wrong. So, before you think about beautifying your new home, think first about fortifying it. Invest in necessary repairs first and avoid surprises down the road.
Go with the pros – When the time does comes to make those changes, be sure to hire the best, most qualified people. This doesn't mean you can't paint or do the little things that can make a big difference. But when it comes to the big stuff, hire the pros for the best results and to avoid injury. Remember, your new home is an investment and it deserves the highest care and attention you can give it.
Practical Advice for New Homeowners
There's nothing more exciting than opening the door to your first new home and knowing that it's actually yours, that you actually own it! No landlord bothering you about every little thing. No silly rules about what colors you can paint or what renovations you want to make. Finally you can do whatever you want to do in your home!
And while this is a great feeling, and the pride you feel is natural and well deserved, don't allow yourself to get too carried away with your newfound freedom. You worked hard to earn this opportunity and you don't want to potentially jeopardize your investment by letting your emotions get the better of you.
If you've recently bought your first home or you plan to do so soon, take a few moments to think about the practical side of home ownership before you start making any major changes or renovations. Doing this will help ensure that your first home becomes the personalized place you always wanted and worked so hard to get.
Get properly insured – Before you decide to build or tear down anything, be sure that you are properly insured. Even if you enjoyed the full $8,000 tax credit for first-time home buyers (or the full $6,500 tax credit now available to qualified "repeat" buyers), sit down with your insurance provider and make sure you're covered on all fronts before you do anything. It doesn't make sense to spend your tax money upgrading your home if you're not protected in advance.
Maintenance before makeover – It's true that you no longer have a landlord looking over your shoulder for every little thing. But, you also don't have a landlord to turn to if something should go wrong. So, before you think about beautifying your new home, think first about fortifying it. Invest in necessary repairs first and avoid surprises down the road.
Go with the pros – When the time does comes to make those changes, be sure to hire the best, most qualified people. This doesn't mean you can't paint or do the little things that can make a big difference. But when it comes to the big stuff, hire the pros for the best results and to avoid injury. Remember, your new home is an investment and it deserves the highest care and attention you can give it.
Tuesday, February 14, 2012
Budgeting for maintenance on a home
It's important to remember that all homes-old or new-need ongoing maintenance.
First, buyers should understand the 1% rule. This rule postulates that normal maintenance on a home is about 1% of the value of the home per year. For example, a $250,000 home would require $2,500 per year to maintain. This would be enough to replace the roof covering...and then, a few years later, to replace a failed hot water tank...and then a few years more until a new central air system is required.
Then there is the 3% rule. Some experts say that home buyers should plan on spending 3% of the value of the home in the first year of ownership. This is because new homeowners will most likely have to buy drapes, blinds, a washer and dryer, a stove, maybe even a new roof covering. Also, new homeowners often customize the environment to their taste, so they need to budget for repairs, replacements and maintenance.
In addition, most home components have fairly predictable life cycles. For example, the typical life cycle of a high-efficiency furnace is 15 to 20 years. What this means is that most high-efficiency furnaces last between 15 and 20 years.
One way to know the extent of the maintenance needed and the costs to repair and/or replace items is to have a home inspection conducted. Home inspectors are required to let the buyer know if a component is significantly deficient or if it is near the end of its life cycle (service life), and a reputable home inspection company may offer up-to-date repair-cost guides to help clients with their planning.
Home inspectors work with Realtors and buyers to help them understand the issues that are found in the home, regardless of age, offering the right perspective and objective information. Home buyers need to understand that it's normal for items in a home to wear out. This should be regarded as normal "wear and tear" and not necessarily a defect.
A good home inspection determines the current condition of the house, offering a report of all the systems and components in need of maintenance, service, repair or replacement.
For example, consider a home inspection that uncovers that the heating system is old and requires replacement. A home buyer may see this as a huge problem. However, this problem may be the only item in the home that requires attention. If a buyer were to look at this situation in perspective, this home could be well above average-a home merely requiring a new furnace.
A good home inspection provides objective information to help the buyer make an informed decision. Knowing what items need to be budgeted for repair or replacement will help home buyers plan or negotiate better and not be stuck with unexpected costs of hundreds, or even thousands of dollars in the long run. Also, fixing these items will make a marked improvement on the performance of a home and minimize issues that could affect its future integrity...and value.
For more information, please contact your local Pillar To Post home inspector.
First, buyers should understand the 1% rule. This rule postulates that normal maintenance on a home is about 1% of the value of the home per year. For example, a $250,000 home would require $2,500 per year to maintain. This would be enough to replace the roof covering...and then, a few years later, to replace a failed hot water tank...and then a few years more until a new central air system is required.
Then there is the 3% rule. Some experts say that home buyers should plan on spending 3% of the value of the home in the first year of ownership. This is because new homeowners will most likely have to buy drapes, blinds, a washer and dryer, a stove, maybe even a new roof covering. Also, new homeowners often customize the environment to their taste, so they need to budget for repairs, replacements and maintenance.
In addition, most home components have fairly predictable life cycles. For example, the typical life cycle of a high-efficiency furnace is 15 to 20 years. What this means is that most high-efficiency furnaces last between 15 and 20 years.
One way to know the extent of the maintenance needed and the costs to repair and/or replace items is to have a home inspection conducted. Home inspectors are required to let the buyer know if a component is significantly deficient or if it is near the end of its life cycle (service life), and a reputable home inspection company may offer up-to-date repair-cost guides to help clients with their planning.
Home inspectors work with Realtors and buyers to help them understand the issues that are found in the home, regardless of age, offering the right perspective and objective information. Home buyers need to understand that it's normal for items in a home to wear out. This should be regarded as normal "wear and tear" and not necessarily a defect.
A good home inspection determines the current condition of the house, offering a report of all the systems and components in need of maintenance, service, repair or replacement.
For example, consider a home inspection that uncovers that the heating system is old and requires replacement. A home buyer may see this as a huge problem. However, this problem may be the only item in the home that requires attention. If a buyer were to look at this situation in perspective, this home could be well above average-a home merely requiring a new furnace.
A good home inspection provides objective information to help the buyer make an informed decision. Knowing what items need to be budgeted for repair or replacement will help home buyers plan or negotiate better and not be stuck with unexpected costs of hundreds, or even thousands of dollars in the long run. Also, fixing these items will make a marked improvement on the performance of a home and minimize issues that could affect its future integrity...and value.
For more information, please contact your local Pillar To Post home inspector.
Friday, February 10, 2012
Windows & Energy Efficiency
A Window on Energy Efficiency
With heating and cooling costs continuing to rise, it makes sense to look at one of the leading causes of energy inefficiency in the home: windows. Installing energy-efficient windows can mean increased comfort as well as savings on utility bills in any climate.
The transmission of air and light is generally the most important function of windows. However, this can mean heat loss in the winter, overheating in the summer, and higher energy bills. In fact, a typical home may lose up to 30% of its heat or cooling through windows. Properly installed, energy-efficient windows can go a long way toward improving this situation.
There are many factors that affect a window’s energy efficiency. Whether they are single- or double-paned, gas filled, Low-Emittance (Low-E) coated, and even the material of the window frame all contribute to a window’s performance. Online resources such as www.efficientwindows.org provide detailed information on these specifications and how to select windows appropriate for various climates. An experienced window contractor can also be a good source of information and recommendations.
Homeowners should check with their local utility company to find out about possible rebates and other incentives for the purchase of new, energy-efficient windows. Window contractors and may also have information on incentives, but be sure to verify any information before committing to the purchase.
Of course, replacing windows is not always a viable option. However, there are steps homeowners can take to improve their energy savings without replacing windows. Making sure windows are properly caulked, keeping weather stripping in good repair, and using storm windows will help. Window coverings are another good way to reduce heat loss in winter and avoid overheating in summer.
Improving energy efficiency throughout the home means cost savings to the homeowner. Energy-efficient windows are a significant step toward that goal.
Article courtesy of Pillar To Post Professional Home Inspection
Pillartopost.com
With heating and cooling costs continuing to rise, it makes sense to look at one of the leading causes of energy inefficiency in the home: windows. Installing energy-efficient windows can mean increased comfort as well as savings on utility bills in any climate.
The transmission of air and light is generally the most important function of windows. However, this can mean heat loss in the winter, overheating in the summer, and higher energy bills. In fact, a typical home may lose up to 30% of its heat or cooling through windows. Properly installed, energy-efficient windows can go a long way toward improving this situation.
There are many factors that affect a window’s energy efficiency. Whether they are single- or double-paned, gas filled, Low-Emittance (Low-E) coated, and even the material of the window frame all contribute to a window’s performance. Online resources such as www.efficientwindows.org provide detailed information on these specifications and how to select windows appropriate for various climates. An experienced window contractor can also be a good source of information and recommendations.
Homeowners should check with their local utility company to find out about possible rebates and other incentives for the purchase of new, energy-efficient windows. Window contractors and may also have information on incentives, but be sure to verify any information before committing to the purchase.
Of course, replacing windows is not always a viable option. However, there are steps homeowners can take to improve their energy savings without replacing windows. Making sure windows are properly caulked, keeping weather stripping in good repair, and using storm windows will help. Window coverings are another good way to reduce heat loss in winter and avoid overheating in summer.
Improving energy efficiency throughout the home means cost savings to the homeowner. Energy-efficient windows are a significant step toward that goal.
Article courtesy of Pillar To Post Professional Home Inspection
Pillartopost.com
CRS Consumer Article
HANDYMAN HELP
HELP FOR HOMEOWNERS: CHOOSING A HANDYMAN
Whether it’s a big project such as a bathroom remodel, something small like putting up shelves, or repairs and routine maintenance, many homeowners turn to handymen to get the job done. It used to be that everyone knew “a guy in town who can do everything”, but these days finding a qualified, professional, and reliable handyman can be a real challenge. Here are some tips to ensure that you choose the right person for the job:
1. MAKE SURE THEY ARE QUALIFIED FOR THE WORK
Certain projects require specific skills that all handymen may not have. You will of course want to know that they have the qualifications and experience to do the job. In addition, many states and provinces require persons performing certain work to be licensed; electrical and plumbing often fall into this category.
2. ASK FOR REFERENCES
Request at least two local references from previous customers. The handyman should be willing to do this without hesitation. Then, contact those references! Ask about the quality of the work, timeliness, professionalism, and how the handyman handled any changes that may have occurred during the course of the project. Also ask how satisfied they were with the work overall.
3. CHECK ON INSURANCE COVERAGE
Liability insurance is always a good idea. If the handyman or another worker is injured while working on your property, you may be held liable for medical costs. Ask for evidence of coverage before agreeing to any work. Uninsured handymen often charge less for their services because they lack the overhead expense of insurance, but it could cost you in the long run.
4. GET WRITTEN ESTIMATES AND A CONTRACT
Ideally, ask three handymen for written estimates for the work you have in mind. Be sure that each estimate contains enough detail so that you can make a comparison between them. For example, are the specified materials of the same quality? Does the cost include cleanup and hauling away any debris or old/broken items? Read all contracts carefully and be sure to ask about anything that you are unsure of.
5. DETERMINE THE PAYMENT SCHEDULE BEFORE YOU SIGN
Beware if you are asked to pay for the entire job up front – this is not an accepted business practice and could leave you open to fraud. Handymen will often ask for 50% when the contract is signed, which will allow them to purchase materials for the job and assure them that you are committed. Be sure to request receipts for all payments.
Article courtesy of Pillar To Post Professional Home Inspection
Pillartopost.com
HANDYMAN HELP
HELP FOR HOMEOWNERS: CHOOSING A HANDYMAN
Whether it’s a big project such as a bathroom remodel, something small like putting up shelves, or repairs and routine maintenance, many homeowners turn to handymen to get the job done. It used to be that everyone knew “a guy in town who can do everything”, but these days finding a qualified, professional, and reliable handyman can be a real challenge. Here are some tips to ensure that you choose the right person for the job:
1. MAKE SURE THEY ARE QUALIFIED FOR THE WORK
Certain projects require specific skills that all handymen may not have. You will of course want to know that they have the qualifications and experience to do the job. In addition, many states and provinces require persons performing certain work to be licensed; electrical and plumbing often fall into this category.
2. ASK FOR REFERENCES
Request at least two local references from previous customers. The handyman should be willing to do this without hesitation. Then, contact those references! Ask about the quality of the work, timeliness, professionalism, and how the handyman handled any changes that may have occurred during the course of the project. Also ask how satisfied they were with the work overall.
3. CHECK ON INSURANCE COVERAGE
Liability insurance is always a good idea. If the handyman or another worker is injured while working on your property, you may be held liable for medical costs. Ask for evidence of coverage before agreeing to any work. Uninsured handymen often charge less for their services because they lack the overhead expense of insurance, but it could cost you in the long run.
4. GET WRITTEN ESTIMATES AND A CONTRACT
Ideally, ask three handymen for written estimates for the work you have in mind. Be sure that each estimate contains enough detail so that you can make a comparison between them. For example, are the specified materials of the same quality? Does the cost include cleanup and hauling away any debris or old/broken items? Read all contracts carefully and be sure to ask about anything that you are unsure of.
5. DETERMINE THE PAYMENT SCHEDULE BEFORE YOU SIGN
Beware if you are asked to pay for the entire job up front – this is not an accepted business practice and could leave you open to fraud. Handymen will often ask for 50% when the contract is signed, which will allow them to purchase materials for the job and assure them that you are committed. Be sure to request receipts for all payments.
Article courtesy of Pillar To Post Professional Home Inspection
Pillartopost.com
Thursday, February 9, 2012
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