The Phenomenon of Phonological Follow in Al-Amali Abi Ali Al-Qali’s Book (seq.356 Hijri): A Phonological Study

This research discusses the verbal follow phenomenon in Al-Amali Abi Al-Qali’s book (seq.356 Hijri). It aims to limit the examples of this phenomenon in the book, and examine it phonologically. Accordingly, the researcher adopted the analaytical descriptive approach, taking into account Al-Rawi’s letter when ordering the verbal follow-based examples, and the order they took in the book in question. The purposes behind this phonological study of verbal follow in Al-Amali’s book are to: reach the sounds which Arabs prefer in the process of following, confirm different beautiful and desirable senses, have easy and speedy pronunciation, maintain harmony between adjacent sounds, count the sounds that occur at the beginning of the follower- a disputable phonological issue between the follower and following- and spot the phonological change that occurs to the follower. Accordingly, a caution is needed to maintain harmony and homogeneity between two pronunciations to achieve the process of following. Or, the structure of the word follower is changed to match its peer followed word.The study has shown that Al-Qali was the eldest in dealing with the formal aspect of the phenomenon. He pointed to the idea of merging the last letter in the subordinate and the follower, and compared it with a stylistic, artistic, and acoustic characteristic, which is included in the innate rhetoric, i.e., assonance. By that, he has determined the most important formal acoustic features of the rhythmic complex as represented by the endings of the sequences, which have a musical rhythm.

Comparison of Declarative-Interrogative Intonation in Lampungnese

Intonation is a suprasegmental feature of language that constructs the meaning of utterances. The meaning constructed can be different from the lexical meaning and syntactical structure. This paper tried to examine the intonation system in the Lampung language, especially the acoustic characteristics which distinguish between declarative and interrogative. In this research, the researcher applied the IPO approach to collect and analyze data. Data were gathered by recording native speakers uttering declarative and interrogative sentences that were segmentally identical. Having the data, a perception test was conducted to get the best utterances for each mode as a contour prototype. Next, both prototypes were analyzed respectively using Praat software to find out each acoustic characteristic. Then, they were compared to find the suprasegmental features that characterize the acoustic features of each sentence mode. Based on the analysis, both intonations differed in the pitch of initial, final subject constituent, final complement constituent, initial predicate constituent, final pitch, peak, range of pitch, and duration of utterances. In addition, pitch of peak (H1) and slope (H2) were identified as the most influential component in the formation of a sentence model. Therefore, experiments of manipulating those acoustic features (H1 and H2) and testing them on the perception of native speakers were held to prove the identification. The result of the perception test showed that the peak significantly distinguished the mode of the sentence, the higher pitch of the peak determined the interrogative mode. While the second identification did not give any contribution in creating the meaning.

Study on Influence of Diameter on Detonation Acoustic Characteristics of Pulse Detonation Engine

The experiment system of pulse detonation engine is set up to investigate on influence of diameter on detonation acoustic characteristic. The research of detonation acoustic characteristic of pulse detonation engine for four different diameters in different angles is carried out. Results from the test show that as the PDE diameter increasing, there are increases in amplitudes of impact noise in all angles, and the growth rate of amplitude of impact noise in the 90° direction is generally greater than that in the 0° direction. The smaller PDE diameter is, the distance of most obvious directivity at 0° turning to most obvious directivity at 30° is shorter. When the distance is shorter, such as 200 mm, the duration of detonation acoustic is increasing with the increase of PDE diameter, however, when the distance is longer, such as 3000 mm, it is just the opposite. The maximum duration of detonation acoustic is appeared in 3000 mm under 30 mm PDE diameter which reaches to 1.44 ms.

Identification of Acoustic Characteristic Parameters and Improvement of Sound Absorption Performance for Porous Metal

Porous metal is widely used in the fields of sound absorption and noise reduction, and it is a critical procedure to identify acoustic characteristic parameters and to improve sound absorption performances. Based on the constructed theoretical sound absorption model and experimental data, acoustic characteristic parameters of the porous metal were identified through the cuckoo search identification algorithm, and their reliabilities were certified through comparing with these labeled parameters and further experimental validation. By adding the microperforated metal panel in front of the porous metal, a composite sound-absorbing structure was formed, which aimed to improve the sound absorption performance of the original porous metal by optimizing the parameters. Finite element simulation and a standing wave tube measurement were conducted to validate the effectiveness and practicability of the optimal composite sound-absorbing structure. Consistencies among theoretical predictions, simulation results, and experimental data proved the effectiveness of the identification and optimization method. When the target frequency ranges were 100–1000 Hz, 100–2000 Hz, 100–3000 Hz, and 100–4000 Hz. Actual average sound absorption coefficients of the optimal composite structures were 0.5154, 0.6369, 0.6770, and 0.7378, respectively, which exhibited the obvious improvements with a tiny increase in the occupied space and a small addition in weight.