Evidence that an employee of a window washing company informed a club's manager that an anchor bolt for attaching safety belts was cracked, and that another employee of the company six months later examined the bolt before attaching his belt and observed a coating of corrosion but no crack, was sufficient to warrant findings that the club was negligent in not warning the second employee of a known hidden defect, and that the second employee was not contributorily negligent. [328-329]
Crack see electrical expert
An answer by an expert witness which contained the words "could," "might well," and "may well" was not mere conjecture where the expert later testified that his answer was based on reasonable scientific certainty. [333-335]
We review the evidence in the light most favorable to the plaintiff. Carr v. Arthur D. Little, Inc. 348 Mass. 469, 471 (1965). Stewart v. Roy Bros. Inc. 358 Mass. 446, 448 (1970). Industrial washed the club's windows from 1961 through 1966, always as a subcontractor of Consolidated, and was the "person responsible" for cleaning the windows at the time of the accident in 1966. Industrial had five or six window washers on its payroll, and its president hired only experienced washers who were "union men." Industrial furnished its employees with all their window washing tools -- safety belts, pails, sponges, squeegees, and ladders -- and the plaintiff was using a bucket, squeegee, and belt supplied by Industrial on the day of the accident. There were no window washers on the club's payroll from at least 1963 up to the time of the accident, and the club owned no window washer's safety belts. The club had three shifts of its own employees to conduct the operation of the club at the time of the accident, which included two full time maintenance men for "the usual carpentry, plumbing and electrical work," a painter, and maids and housemen. On occasion it was necessary for one of these employees to clean a window when the "contract window cleaners" were not there, but the club's manager had never seen one of its employees use a window washer's belt, and none of them participated in the window cleaning operation described in the club's contract with Consolidated. The contract between the club and Consolidated in effect at the time of the accident required that all windows on the first and second floors be washed on a monthly basis and all other windows in the building be washed semi-annually. The plaintiff was engaged in one such semi-annual washing at the time he fell. In the opinion of the club's manager, window washing was a very minor part of the overall operation of the club.
The evidence would have permitted the jury to find the following. The valet room anchor bolt which broke and caused the plaintiff to fall was made of cast bronze and there were defects in its casting; the bolt was corroded, thereby causing a smooth, green coating to form which covered its surface. On the date of the accident, the plaintiff inspected the bolt before and after he hooked his safety belt onto it and saw the green coating but no cracks. Six months prior to the plaintiff's accident, John Duffy, another window washer employed by Industrial, had examined the anchor bolt in question and had seen a crack in the neck of the bolt. He had informed the club's manager that the bolt was rotted and cracked, asked him if he would check the bolts in the valet room and told him the bolts should be replaced by steel hooks. Duffy did not tell the plaintiff about his discovery. The club's manager had no recollection that he or anyone on his behalf had specifically inspected the bolts. During his tenure (since 1963) the club had no inspection or maintenance program which required the anchor bolts to be checked or inspected.
We do not agree with the club that because Duffy testified to having seen a crack in the anchor bolt six months before the plaintiff's accident, the plaintiff is barred from recovery. The plaintiff testified that Duffy had not told him about the defective bolt, and in any event, he is not bound by Duffy's testimony as it did not relate to the extent of his own knowledge. Cf. Hannon v. Hayes-Bickford Lunch Sys. Inc., supra, at 273; Findlay v. Rubin Glass & Mirror Co. 350 Mass. 169, 171-172 (1966). [Note 5]
We also conclude that the jury could find that the violation of Section 10 was causally related to the plaintiff's injuries. All the evidence on the point tended to show that the anchor bolt broke because of defects in the casting. From the testimony of the plaintiff's expert witness to the effect that the "defects in the casting [were] caused by the shrinking of the liquid metal as it freezes, causing voids or hollow spaces, and . . . hot tear[s]," and from his testimony describing the difference between casting and forging procedures, the jury could infer that such defects would not have existed in a bolt made of forged metal, as required by the regulation. The question whether the violation of a
Dr. Carl Floe, a professor of metallurgy at Massachusetts Institute of Technology, was called by the plaintiff to testify as an expert with reference to the anchor bolt involved in the plaintiff's fall and resulting injury. In direct testimony, after he described the bolt and various tests which he performed on it, he was asked a hypothetical question which asked him to assume various facts and then concluded: "[D]o you have an opinion with reasonable scientific certainty, based upon your education, training, experience and background in the metallurgy field, as to the cause of the breaking or failure of the bolt in question known as Exhibit 19?" The witness answered that he did have such an opinion and he was then asked what it was. His answer is set forth in full in the margin. [Note 6] Counsel for the
The basic issue is whether we are dealing with "[a] mere guess or conjecture by an expert witness in the form of a conclusion from basic facts that do not tend towards that conclusion any more than towards a contrary one [and therefore] has . . . no evidential value" (Ruschetti's Case, 299 Mass. 426, 431 [1938]; Hachadourian's Case, 340 Mass. 81, 85-86 [1959]; Berardi v. Menicks, 340 Mass. 396, 401-402 [1960]; Oberlander's Case, 348 Mass. 1, 5-6 [1964];
The club also argues that the answer of the expert witness should have been struck because it was not responsive to the question. The motion was to strike the entire answer, and it was not limited to any particular part which was claimed to be unresponsive. The first part of the answer was clearly responsive, and the court was not required to allow such a motion unless no part of the answer was responsive. Since "[t]he motion to strike was too broad, for it included competent as well as incompetent evidence," it was properly denied. Bryer v. P. S. Thorsen Co. of Mass. 327 Mass. 684, 687 (1951). See Commonwealth v. Zaidon, 253 Mass. 600, 602 (1925).
The club has urged on us the further argument that the answer of the expert should be struck because it "included evidence incompetent because based upon unwarranted assumptions." This ground is not now open to the club because it was not included in the grounds stated to the trial judge as the basis for the motion. "Having stated specifically the basis of . . . [its motion], the defendants, in fairness, ought not to be permitted to urge other grounds in this court." Kagan v. Levenson, 334 Mass. 100, 107 (1956). Draper v. Turner, 339 Mass. 616, 618 (1959).
[Note 5] There was testimony by the plaintiff's expert witness which tended to explain how a crack could have been visible on the anchor bolt in October and then could have been covered over and hidden by the following April. We consider later in the opinion exceptions raised by the club with respect to this testimony but as our discussion above indicates, we have concluded that even without it the jury would be permitted to find that the defective condition of the anchor bolt was hidden at the time of the plaintiff's accident in April, 1966.
[Note 6] "My opinion is that this was a defective casting, to start with; that even in October, 1965, it must have been close to the point of failure. In other words, there were sufficient cracks and voids and discontinuities in this particular area where the fracture occurred to make it a very weak material.
"I think that the man who was washing the window in October, '65, may well have opened up one of these cracks to make it visible as he put the channel onto the anchor, jerked on it, put loads on it with his body in different directions. He could open up one of these cracks to make it visible through the copper-carbonate deposit, which is a very brittle deposit.
"I think subsequent to this, further corrosion had occurred not only on the surface but now down in the opened-up crack. In other words, moisture containing these corrosive agents would seep into this crack, would corrode it, products of corrosion would expand and could well conceal the crack so that a man in April, 1966 may well not have observed it."
Silicon carbide is a unique semiconductor utilized in a variety of demanding applications where it can be exposed to extreme environments, such as high-power operation and elevated temperatures. The mechanical reliability of such devices must also be well understood to optimize device lifetime, where failure generally occurs by brittle crack growth. One means in which failure by crack growth can be partially mitigated is through crack healing. Crack healing is an interesting process where bonds can be repaired across a closed crack, and is generally assisted by electrical, thermal, and chemical means.
This study reports on in situ TEM tensile testing of both amorphous and single crystal SiC nanowires using a Hysitron PI95 TEM Picoindenter and the push-to-pull (PTP) device. The nanowires were prepared using a novel approach with an eyebrow hair as the manipulator, together with silver-filled adhesive to avoid potential FIB damage. Both types of nanowires exhibited multiple crack healing and re-fracture events. This was examined in greater detail using high-resolution TEM and molecular dynamics simulations. The mechanism of crack healing was found to be atomic diffusion, which underwent partial recrystallization and recovered a portion of the original nanowire strength. Since this was done in a vacuum, the fracture surfaces did not oxidize and the reduction in surface energy drove the healing process requiring, no external energy input. 2ff7e9595c
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