Пилотное исследование эффективности использования фотодиодного сенсора в качестве дозиметра

Radiation dosimetry in the health and medicine field is crucial to ensure there is no unnecessary ionizing radiation exposure to patients and personnel. While various types of semiconductor dosimeters are available, photodiode sensors are seen as a reliable and cost-effective immediate dosimeter. This study investigates the capabilities of a monolithic photodiode with an on-chip trans-impedance amplifier as a dosimeter in diagnostic radiology. A photodiode sensor covered with black insulation tape is irradiated with the diagnostic x-ray of potential in range between 40 to 90 kV with constant tube current-time product of 50 mAs at 60 cm source-to-detector distance (SDD). Exposures of different tube current at the range of 10 to 250 mA with a constant tube voltage of 70 kVp at the same setup are made. The photodiode sensor connected to the electrometer gives out readings in the millivolt (mV), and the output of the photodiode and semiconductor detector is recorded. The photodiode’s energy dependency, reproducibility, dose response, and distance dependency were evaluated as the capabilities of the photodiode to be used as a dosimeter. For energy dependency, it shows a linearity of 0.9458, while the response to increasing tube current with a constant tube voltage shows the R2 of 0.912. The photodiode shows good dependency on the tube voltage and tube current. Other than that, it also showed a linear coefficient of 0.5138 for distance dependence which is considered as a good linearity fit value for a photodiode as initial performance. However, its reproducibility is poor due to its large capacitance. This monolithic photodiode with an on-chip trans-impedance amplifier has demonstrated good results for energy dependency but poor results for reproducibility. However, the photodiode can be improvised in the future to ensure it is suitable as a dosimeter.Дозиметрия излучения в области здравоохранения и медицины имеет решающее значение для предотвращения ненужного воздействия ионизирующего излучения на пациентов и персонал. Несмотря на доступность различных типов полупроводниковых дозиметров, фотодиодные датчики считаются надежными и экономичными непосредственными дозиметрами. В этом исследовании изучаются возможности использования монолитного фотодиода со встроенным трансимпедансным усилителем в качестве дозиметра в диагностической радиологии. Фотодиодный датчик, покрытый черной изоляционной лентой, облучался диагностическим рентгеновским излучением в диапазоне напряжений на излучателе от 40 до 90 кВ с постоянной экспозицией 50 мАс с расстояния в 60 см до детектора (SDD). На одной и той же установке производятся воздействия различного тока трубки в диапазоне от 10 до 250 мА с постоянным напряжением трубки 70 кВ. Фотодиодный датчик, подключенный к электрометру, выдает показания в милливольтах (мВ), а выходной сигнал фотодиода и полупроводникового детектора записывается. Энергетическая чувствительность фотодиода, воспроизводимость, реакция на дозу и зависимость от расстояния были оценены как возможности фотодиода для использования в качестве дозиметра. Для зависимости от энергии он показывает линейность 0,9458, в то время как для реакции на увеличение тока трубки при постоянном напряжении трубки R2 равен 0,912. Фотодиод показывает хорошую зависимость от напряжения лампы и тока трубки. Помимо этого, он также показал линейный коэффициент 0,5138 для зависимости от расстояния, который считается хорошим значением при линейной подгонке для фотодиода в качестве начальных характеристик. Однако его воспроизводимость недостаточно высока из-за большой емкости. Таким образом, изучаемый монолитный фотодиод со встроенным трансимпедансным усилителем показал хорошие результаты по энергетической зависимости, но низкие результаты по воспроизводимости. Тем не менее, в будущем фотодиод может быть усовершенствован, чтобы обеспечить его пригодность в качестве дозиметра

Carbonization cbn550 effect on tensile properties of composite for marine structure application

The composites have gained commercial success, where strength, stiffness, durability and light weight are required as well as retardant capacity. Improvement has been made such new series of resin such as vinyl ester and epoxy type[1, 2]. However 95% of pleasure vessels and boats under 60 feet today are still made with polyester resin. The main consideration for most composite builders is cost, with performance and more importantly value for money often being a secondary consideration. Therefore, this study investigate the tensile - mechanical effects of mixing carbon black CBN550 with wax and non-wax type resin and manufactured according to fiber orientation of [0°] and [90°]. The 10% CBN550 exhibit highest reading for stress under [90°] fiber orientation and the lowest reading when arranged at [0°] fiber orientation. The preliminary study on CBN550 flammability has indicated the suitability for this study to pursue in. The structural composites samples of 1000 mm by 1000 mm prepared which consist of 10 of composite mats layer in combination of CSM 450 g/m2 and Woven Roving 600 g/m2. The carbon black (CB) volume fraction range from/with 0% to 20% volume fractions. Optical observation revealed the most suitable fraction of CBN550 in wax polyester resin is at 10% and non-wax polyester resin is also at 10%. The fire resistance behaviour of this CBN550 - CSM 450 g/m2 - Woven Roving 600 g/m2 composite (polyester wax) and polyester non wax was investigated previously as per[3]. This results are in line with the finding of the maximum load where the highest reading was recorded by the 10%CBN550 specimen. This study showed that the introduction of carbon black into the resin mixture helps reinforce the matrix materials. The results suggested that CBN550 mixture should attend to next level of experiment investigation such as oxygen content, TG value, microstructure and other mechanical destructive test. The CBN550 could be a suitable candidate for fire retardance application in marine composite structure

Masalah disiplin murid Islam: strategi dan penyelesaian terhadap kurikulum Pendidikan Islam

Kajian ini dilaksanakan untuk mengenal pasti jangkaan masa depan mengenai masalah disiplin murid Islam dalam aspek amalan beragama dan strategi penyelesaian dalam aspek proses pengajaran dan pembelajaran kurikulum Pendidikan Islam. Untuk menjawab objektif tersebut, data dikutip menggunakan kajian Delphi sebanyak tiga sesi pusingan. Peserta kajian adalah dalam kalangan sepuluh orang pakar dalam bidang kepimpinan sekolah. Pada sesi pusingan pertama, data dikutip menggunakan kaedah temu bual. Dapatan temu bual tersebut telah membentuk item soal selidik bagi kegunaan Delphi sesi pusingan kedua dan ketiga. Data temu bual dianalisis menggunakan pendekatan tematik. Manakala, data soal selidik menggunakan kaedah statistik deskriptif iaitu median dan Julat Antara Kuartil (JAK). Kajian ini memperoleh tahap kesepakatan pakar yang tinggi untuk menyetujui setiap item apabila skor median melebihi 4 dan JAK kurang daripada 1. Dapatan kajian menemui jangkaan masalah disiplin murid Islam dalam aspek amalan beragama dengan bilangan tema dan subtema seperti berikut iaitu akhlak sebanyak 3 item, amalan membaca al-Quran (3 item), amalan solat (3 item), kesedaran terhadap hukum hakam (5 item), aktiviti bersosial (3 item) dan penggunaan bahan tegahan (3 item). Manakala, jangkaan strategi penyelesaian kepada masalah disiplin murid Islam dalam aspek pengajaran dan pembelajaran kurikulum Pendidikan Islam dengan bilangan tema dan subtema seperti berikut iaitu akhlak sebanyak 7 item, amalan membaca al-Quran (6 item), amalan solat (5 item), kefahaman terhadap hukum hakam (5 item), aktiviti bersosial (3 item) dan penggunaan bahan tegahan (4 item). Implikasi kajian ini adalah perlunya mengambil kira pandangan individu bergelar pakar dalam bidang tertentu dalam proses pembuatan keputusan

The effect of N550 carbon black in polyester resin for fire-retardant application in marine composite

This paper presents the experimental investigation on the influence of N550 carbon black (CBN550) series in polyester resin (wax and non -wax type). The CBN550 was added into polyester resin at different weight percentages with a curing agent. The investigation is mainlyto study the effect on fire retardance application in marine composite structure. The fire-resistant structural composites samples of 1000 mm by 1000 mm prepared which consist of 10 of composite mats layer in combination of CSM 450 g/m2 and Woven Roving 600 g/m2. The carbon black (CB) volume fraction range from/with 0% to 20% volume fractions. Optical observation revealed the most suitable fraction of CBN550 in wax polyester resin is at 10% and non-wax polyester resin is also at 10%. The fire resistance behavior of this CBN550 - CSM 450 g/m2 - Woven Roving 600 g/m2 composite (polyester wax) and polyester non wax was investigated by Fire Test Procedure Code-Resolution A.653 [1]. Though smaller filler size escalates the rheological behavior and values outstandingly at initial reading compare to large particles but it slow down the curing processdue to its small particle size, large surface area and high dispersion rate. Experimental data showed the retardance level has been increased up to 56.66% in non-wax type polyester resin (10%/CBN550) and 30.14% in wax polyester resin (10%/CBN550). The improvement in fire resistance points are due to the presence of CBN550 which acts as a positive additive in both polyester resin wax and non-wax. Filling CBN550 in polyester resin also reduces the cost of theend products.The preliminary results suggested that CBN550should attend to next level of experiment investigation such as oxygen content, TG value, microstructure as well as mechanical destructive test. The CBN550 could be a suitable candidate for fire retardance application in marine composite structure.In conclusion, crystallinity of polyester resin increases with additional of CB particles

Validating The Impact of Psychological, Physical, and Social Factors On Workplace Well-Being at Construction Sites

A good workplace well-being environment can increase employee resilience, work engagement, project performance, and productivity, as well as reduce sick days. Research suggests that physical, psychological, and social factors are the underlying factors for a good workplace well-being However, the underlying factors for workplace well-being at construction sites may differ. This study aims to validate the relationships between underlying factors (i.e., physical, psychological, and social) and workplace well-being at construction sites. A questionnaire survey was developed from a list of factors influencing workplace well-being and distributed to construction professionals. The collected data was analyzed using confirmatory factor analysis (CFA) to validate the relationships between the underlying factors and workplace well-being at construction sites. The analysis revealed that physical, psychological, and social factors are also influencing workplace well-being at construction sites. Researchers and industry practitioners can use these findings to confidently establish strategies to increase workplace well-being of construction workers

Mechanical performance of roselle/sugar palm fiber hybrid reinforced polyurethane composites

The effect of sugar palm fiber (SPF) loading was studied relative to the mechanical properties of roselle (RF)/SPF/thermoplastic polyurethane (TPU) hybrid composites. RF/SPF/TPU hybrid composites were fabricated at different weight ratios (100:0, 75:25, 50:50, 25:75, and 0:100) by melt mixing and hot compression. The mechanical (tensile, flexural, and impact test) and morphological properties of tensile fractured samples were examined using a universal testing machine, impact machine, and scanning electron microscope. It was found that the hybridization of RF/SPF increased its impact strength corresponding to the increases in the SPF content of the composites. The tensile and flexural properties of the hybrid composites decreased due to poor interfacial bonding between the fiber and matrix. Scanning electron micrographs of the tensile fractured surface of the RF/SPF hybrid composites revealed fiber pullouts and poor adhesion bonding. In conclusion, the hybridization of SPF with RF/TPU composites enhanced its impact strength while decreasing the tensile and flexural strength

Validating The Impact of Psychological, Physical, and Social Factors On Workplace Well-Being at Construction Sites

A good workplace well-being environment can increase employee resilience, work engagement, project performance, and productivity, as well as reduce sick days. Research suggests that physical, psychological, and social factors are the underlying factors for a good workplace well-being However, the underlying factors for workplace well-being at construction sites may differ. This study aims to validate the relationships between underlying factors (i.e., physical, psychological, and social) and workplace well-being at construction sites. A questionnaire survey was developed from a list of factors influencing workplace well-being and distributed to construction professionals. The collected data was analyzed using confirmatory factor analysis (CFA) to validate the relationships between the underlying factors and workplace well-being at construction sites. The analysis revealed that physical, psychological, and social factors are also influencing workplace well-being at construction sites. Researchers and industry practitioners can use these findings to confidently establish strategies to increase workplace well-being of construction workers

Micromechanical Studies of 4n Gold Wire for Fine Pitch Wirebonding

This study focuses towards typical micromechanical properties such as strength, yield point, Young’s Modulus, strain, shapes of fracture end and element analysis, atomic percentage of Ca of 4N gold (Au) wire using microstructures and composition observation, micro-tensile test and depth sensing indentation technique. A series of micro-tensile test were performed with different strain rate values of 10˚-10-4 min-1 on to a 25.4 μm diameter plain gold wire. The nanoindentation with 20 mN maximum load was indented on a near fracture end of a gold wire specimen, for which this test was carried out after the micro-tensile test. The stress-strain curves were used to characterize the 4N purity gold wire. The shapes of fracture end of gold wire after micro tensile test were carried out using Scanning Electron Microscopic (SEM). The finding showed that the mechanical properties of ultra-fine gold wire was in the proportional relationship with the increment of the strain rate value. It is suggested that micromechanical behaviour gave the effect for the wirebonding process in order to characterize the wire loop control and strengthen the wire loop to avoid the wire sweep

Theoretical investigations of β-tricalcium

Beta-tri-calcium phosphate (β-TCP) materials have gained a great deal of research considerations in biomaterial area due to their excellent biocompatibility and identical chemical compositions to the natural teeth and bones. Therefore, the β-TCP compound can be used as coatings, cement and composites as well as biocompatible ceramics for medical and dental applications. Electronic and optical properties for β-TCP compound have been investigated using density functional theory (DFT). For the calculations, we used full potential linear augmented plane wave method (FPLAPW), within three types of approximations along with local density approximations (LDA), generalized gradient approximations (GGA) and Modified Becke-Johnson (mBJ) to get the effect of the exchange and correlation in our calculations to get an accurate results. The computed band gap values for (β-TCP) compound using LDA, GGA, and mBJ-GGA approximations are 5.5 eV, 5.9 eV and 6.8 eV respectively. This is also predicted that the chemical bonding in this compound is a kind of combination of covalent and ionic character that is in a line with the experimental findings. The optical parameter, static dielectric constant ε1(0) reaches the values of 3.23681 (eV) at 0 GPa for the β-TCP compound. The obtained results are of vital nature for rising the quality of the electronic and optical properties of this material, and provide more evidence to fabricate novel Beta-Tri-calcium phosphate biomaterials for medical and dental applications