ABSTRACT
The palm and date sector is one of the most important sectors in Saudi Arabia. The total number of fertile palm trees in Saudi Arabia is about 31 million. In the production of pitted dates, date molasses, date paste, and date confectionery, a considerable number of date kernels are usually discarded as waste. This study reports experimental investigations conducted to evaluate the potential of waste date kernel ash (DKA), obtained by the calcination of date pits at 800 °C, as a partial cement replacement in concrete. DKA has low silica oxide and does not qualify as a pozzolanic material. The effect of DKA partially replacing the cement and acting as a filler material in concrete was investigated, and its properties were compared with two pozzolanic materials, fly ash (FA) and natural pozzolan (NP). Twelve concrete mixes in which cement was replaced with different proportions of calcined DKA (5%, 10%, 15%, 20%, and 30%), NP (10%, 20%, and 30%), and FA (10%, 20%, and 30%) were investigated in the experimental program. The properties of DKA, FA, and NP concrete mixes were evaluated in fresh and hardened states, including the heat of hydration, mechanical characteristics, and thermal properties. The results show that replacing cement with 5% date kernel ash increases the compressive strength by 0.42%, 3.2%, and 2.5% at 3, 7, and 28 days, respectively, while the 28-day compressive strength decreases by 2.4%, 5.4%, 16.3%, and 26.69% when the cement is replaced with 10%, 15%, 20%, and 30% DKA, respectively. Date kernel ash concrete mixes with 10%, 20%, and 30% replacement levels demonstrated higher compressive and tensile strengths and lower thermal conductivity, density, and workability when compared to natural pozzolan and fly ash. DKA is a promising partial cement replacement material; nevertheless, additional research is required to assess the durability of DKA in concrete.
ABSTRACT
To evaluate predictive value of high resolution computed tomography in atticoantral disease. We conducted a prospective observational study in 49 patients suffering from atticoantral disease at tertiary referral institute. Preoperatively, all the patients underwent unenhanced high resolution computed tomography (HRCT) of temporal bone parallel to orbitomeatal line by using multislice scanner. We evaluated presence of soft tissue attenuation, ossicular erosion, facial canal erosion, dural exposure, erosion of semicircular canal, labyrinthine fistula, erosion of scutum and tegmen tympani in CT scan. HRCT is recommended in atticoantral disease with complications. This study demonstrates the predictive value of HRCT of temporal bone as a diagnostic modality in atticoantral disease. HRCT shows 100% sensitivity (Sn) of soft tissue density detected in middle ear, aditus and attic. Specificity (Sp) was more for eustechian tube area and sinus tympani. Ossicular erosions of malleus (Sn = 90.9%, Sp = 75%), incus (Sn = 93.2%, Sp = 80%), stapes (Sn = 78.8%, Sp = 68.8%) were detected. Erosion of scutum (Sn = 94.1%, Sp = 80%), tegmen (Sn = 66.7%, Sp = 100%), sinus plate (Sn = 100%, Sp = 97.9%), facial nerve canal (Sn = 75%, Sp = 100%), semicircular canal fistula (Sn = 80%, Sp = 97.7%) and cochlear promontory fistula (Sn = 50%, Sp = 97.9%) were evaluated. HRCT temporal bone helps to evaluate disease extent and involvement of surrounding structures. Hence it helps in deciding surgical approach and also prevents impending complications.
