Characterization of measured lightning electric fields observed in Malaysia

This paper presents a characteristic of lightning electric fields. The lightning electric fields captured by two parallel plats sensor and the characterization for preliminary breakdown pulse (PBP) and first return stroke (RS) were studied. A total of 207 data were recorded and 10 data are selected and been utilized in this paper accordingly. In PBP signal data, time before return stroke, ending time and maximum peak of PBP were analyzed. The time duration between the PBP and the occurrence of RS was obtained as 0.64 ms and 2.61 ms and then compared with results from other researchers. For RS signal data, slow front time, deviation time, RS peak, time to peak, zero crossing time and 10% to 90% rise time were evaluated meticulously and the results were discussed accordingly. Moreover, the statistical correlation between electric field zero times and corresponding rise times was studied

Unique stroke-multiplicity of positive lightning in Malaysia

This paper presents the unique characteristics of positive lightning generated vertical electric field waveforms recorded in Malaysia. The focus of the study was the waveforms due to positive lightning and their number of return strokes in a flash. A total of 172 lightning ground flash records were analysed, out of which 57 flashes contained positive lightning with a number of them having high numbers of subsequent return strokes which is somewhat unusual with observations elsewhere. The field measurements were done by using a parallel plate antenna coupled with a recording system. In contrary to the majority of positive lightning return strokes that has been recorded previously, where the average multiplicity is one, this study showed an average multiplicity of 3.86 which is almost four times higher than that is usually observed

Characterization preliminary breakdown in the measured lightning electric fields

In this study, characterization of measured electric fields due to lightning channel was done. Likewise, previous studies on this case were reviewed and discussed accordingly. Furthermore, preliminary breakdown was done in detail and it was indicated on the real measured electric fields and the results were discussed. The behavior of preliminary breakdown signal was observed. This study shows that it will be easier to design filtering of the preliminary breakdown. The result show compelling agreement with theoretical predictions and significant improvement over previous effort by Clarence and Malan, Weidman and Krider and Rakov, et al. the work presented here has profound implications for future studies of Preliminary Breakdown and may one day help solve the problem of designing protection level for Electrical Engineers. The results show that the occurrence of PBP is in between 2 to 10 milliseconds before return stroke as agreed with Clerence and Malan

Distinct position of chaotic pulse trains observed in Malaysia

This paper presents the chaotic pulse train (CPT) waveforms of the vertical electric field generated by lightning observed in Malaysia. Focusing on the position where these electric field changes occur in a number of cloud to ground (CG) flashes, these CPTs were detected in different ways of occurrences, durations, intensities and amplitudes. Seventy-six chaotic pulse trains were found in this study from a sum of 172 CG flash records from three thunderstorm days. The fast field antenna was employed to do the field measurements. As opposed to the typical occurrence of chaotic pulse trains prior to subsequent strokes as reported in the literature, this study has found chaotic pulse trains occurring in different places along the CG electric field waveforms

Distinct characteristics of cloud-to-ground lightning electric fields generated in Malaysia

Lightning generates electric fields that propagate through the vicinity of the atmosphere that have negative consequences especially to power, electronic and communications systems. Knowledge to the types of lightning and their characteristics must be acquired to fulfil the task of mitigating lightning problems. Most studies regarding the topic were done in temperate and sub-tropic regions. Thus, this study seeks to uncover better understanding of the lightning generated electric fields of cloud-to-ground lightning flashes observed in Malaysia in the tropics. Measurements of the generated fields were done using parallel plate antenna coupled with a recording system during the months of May, June and October 2013 at the premises of Universiti Putra Malaysia. The measurement site has a geographical coordinate of 2°59'19.9"N latitude and 101°43'29.8"E longitude, situated in Serdang, Selangor area. Malaysia generally has a tropical climate with maximum monsoon rain occurring from October due to southwest monsoon and intermonsoon period which affects the Selangor. The locations of some of the flashes were obtained from the Tenaga Nasional Berhad Research which is a research centre for the largest local power utility company, Tenaga Nasional Berhad using their Fault Analysis and Lightning Location System. This thesis presents the characteristics of lightning generated vertical electric field waveforms recorded in Malaysia. A total of 115 negative lightning and 57 positive lightning found with preliminary breakdown pulses, return strokes and chaotic pulse trains were present and analysed. The main findings of this study include characteristics of preliminary breakdown pulses, unusually long duration return strokes lasting more than 1 ms per stroke, occurrence of positive lightning and chaotic pulse trains in Malaysia with average durations of 335.12 μs for both negative and positive lightning combined, high multiplicity of positive lightning return strokes having an average multiplicity of 3.86, short interstroke intervals of positive lightning with an arithmetic mean of 25.03 ms, occurrence of chaotic pulse trains in positive lightning and unusual occurrences of chaotic pulse trains in terms of their placement in both types of lightning. In conclusion, the findings of the electric field generated in Malaysia were found to be distinct in many ways that adds to new knowledge from the findings previously mentioned. This is important as the kind of lightning activity affects the way in which protection systems are made

Gravity Analysis for Subsurface Characterization and Depth Estimation of Muda River Basin, Kedah, Peninsular Malaysia

Gravity survey is one of the passive geophysical techniques commonly used to delineate geological formations, especially in determining basement rock and the overlying deposit. Geologically, the study area is made up of thick quaternary alluvium deposited on top of the older basement rock. The Muda River basin constitutes, approximately, of more than 300 m of thick quaternary alluvium overlying the unknown basement rock type. Previous studies, including drilling and geo-electrical resistivity surveys, were conducted in the area but none of them managed to conclusively determine the basement rock type and depth precisely. Hence, a regional gravity survey was conducted to determine the thickness of the quaternary sediments prior to assessing the sustainability of the Muda River basin. Gravity readings were made at 347 gravity stations spaced at 3–5 km intervals using Scintrex CG-3 covering an area and a perimeter of 9000 km2 and 730 km, respectively. The gravity data were then conventionally reduced for drift, free air, latitude, Bouguer, and terrain corrections. These data were then consequently analyzed to generate Bouguer, regional and total horizontal derivative (THD) anomaly maps for qualitative and quantitative interpretations. The Bouguer gravity anomaly map shows low gravity values in the north-eastern part of the study area interpreted as representing the Main Range granitic body, while relatively higher gravity values observed in the south-western part are interpreted as representing sedimentary rocks of Semanggol and Mahang formations. Patterns observed in the THD anomaly and Euler deconvolution maps closely resembled the presence of structural features such as fault lineaments dominantly trending along NW-SE and NE-SW like the trends of topographic lineaments in the study area. Based on power spectral analysis of the gravity data, the average depth of shallow body, representing alluvium, and deep body, representing underlying rock formations, are 0.5 km and 1.2 km, respectively. The thickness of Quaternary sediment and the depth of sedimentary formation can be more precisely estimated by other geophysical techniques such as the seismic reflection survey

Giant Vesicles (GV) in colloidal system under the Optical Polarization Microscope (OPM)

This paper discusses the unprecedented microscopic findings of micellar growth in colloidal system (CS) of catalyzed piperidinolysis of ionized phenyl salicylate (PS−).The giant vesicles (GV) was observed under the optical polarization microscope (OPM) at [NaX] = 0.1 M where X = 3-isopropC6H4O−. The conditions were rationalized from pseudo-first-order rate constant, kobs of PS− of micellar phase at 31.1 × 10−3 s−1 reported in previous publication. The overall diameter of GV (57.6 μm) in CS (CTABr/NaX/H2O)-catalyzed piperidinolysis (where X = 3-isopropC6H4O) of ionized phenyl salicylate were found as giant unilamellar vesicles (GUV) and giant multilamellar vesicles (GMV). The findings were also validated by means of rheological analysis

Abstracts of the International Halal Science Conference 2023

This book presents the extended abstracts of the selected contributions to the International Halal Science Conference, held on 22-23 August 2023 by the International Institute for Halal Research and Training (INHART), IIUM, Malaysia in collaboration with Halalan Thayyiban Research Centre, University Islam Sultan Sharif (UNISSA), Brunei Darussalam. With the increasing global interest in halal products and services, this conference is timely. Conference Title:  International Halal Science ConferenceConference Acronym: IHASC23Conference Theme: Halal Industry Sustainability Through ScienceConference Date: 22-23 August 2023Conference Venue: International Islamic University (IIUM), MalaysiaConference Organizer: International Institute for Halal Research and Training (INHART), International Islamic University (IIUM), Malaysi