Two hundred twenty-three cases of inverted papilloma seen at this institution over a 35-year period were reviewed. The number of cases steadily increased over each 5-year period. Common presenting signs and symptoms, association with carcinoma, and results of surgical and radiographic treatment are presented. The pathologic controversy surrounding this disease is discussed, and an argument is made for including all pathologic subtypes and septal, lateral wall, or sinus cases in a common clinical grouping of inverted papilloma. Lateral rhinotomy was found to be associated with fewer recurrences and a better probability of cure than lesser procedures and is recom mended as the standard surgical therapy. Radiotherapy was found to be a useful and effective adjunct in cases associated with malignancy or for multiply recurrent and inoperable benign inverted papillomas. Lifelong follow-up is urged.KEY WORDS -inverted papilloma, nasal cavity, papilloma, paranasal sinuses.

Most highway agencies have decades of experience with hot-mix asphalt whose percentage of reclaimed asphalt pavement (RAP) has remained low to moderate because of the general perception that RAP mixtures may be more susceptible to various modes of cracking. As the RAP proportion increases, so does the potential for an increase in mixture stiffness and a decrease in resistance to cracking. Two proposed ways to increase the durability of RAP mixtures are to (a) increase the amount of virgin binder in the asphalt mixture and (b) decrease the performance grade of the virgin binder. To assess these options, 0%, 25%, and 50% RAP mixtures at optimum asphalt content were designed with a standard PG 67-22 virgin asphalt binder. These mixtures were tested to evaluate surface cracking, reflection cracking, and rutting with the use of an energy ratio, overlay tester, and asphalt pavement analyzer, respectively. These tests also were conducted on RAP mixtures with 0.25% and 0.50% higher asphalt contents and at the optimum asphalt content with the use of a softer virgin binder. In addition, the linear amplitude sweep methodology was used to assess the fatigue properties of the blended binders. The results showed that, to improve resistance to cracking, the amount of virgin asphalt should be increased by 0.1% for every 10% of RAP binder in the mixture for up to 30% RAP binder. Once the RAP binder exceeds 30%, a softer grade of asphalt should be used to increase the mixture's resistance to cracking. All mixtures should be assessed for rutting susceptibility.

No abstract

An effort is made to summarize current practices for modifying paving asphalts. The types and classes of modifiers used, or considered, for paving applications are reviewed. The applicability of the Superpave binder specification (AASHTO MP1) is reviewed critically, and the modified-asphalt characteristics that are not considered in this specification are evaluated. Conventional testing results of modified binders are compared with Superpave testing results. The results indicate that a variety of additives can be classified, on the basis of their composition and their effects on asphalts, as polymers (elastomeric and plastomeric), fillers, fibers, hydrocarbons, antistripping agents, oxidants, antioxidants, crumb rubber, and extenders. These additives vary significantly in their physical and chemical characteristics and are expected to have widely variable effects on performance-related properties of asphalts. The assumptions supporting the criteria in the Superpave binder specification may not be valid for some modified binder systems. Furthermore, the testing protocols included in the specification do not consider certain important characteristics that are typical of particular modified binders. Among these characteristics are strain dependency, thixotropy, loading-rate dependency, and time-temperature equivalency. Conventional measurements used currently by state departments of transportation such as ductility, elastic recovery, and resilience, were collected. The ranking of five modified systems on the basis of conventional and Superpave measurements was analyzed. The analysis does not indicate that the conventional test methods are consistent in their rankings, nor does it indicate that these measures add much to the information deduced from the Superpave data.

The hydraulic properties of commercial well screens were investigated to determine which screen design features affected head loss. The test program began with laboratory experiments and continued as a field‐scale experiment with the installation of a well field in the Thames Valley Gravel Aquifer. The laboratory experiments indicated that, for all practical purposes, the head loss attributable to all of the screens tested was negligible. The experimental head loss, however, did vary from screen to screen, particularly at high intake velocities, and the screens could be ranked on the basis of their hydraulic efficiencies. This efficiency hierarchy is explained tentatively in terms of the screen construction methods and slot geometry. The field experiments showed that the hydraulic performance of all well screens is independent of screen design provided that the open area of the screen is above about 10%. The field experiments also indicated that the development capacity of a screen in a gravel aquifer is not wholly dependent on screen design, but that progressive development does increase the hydraulic efficiency of a well.