Analisis Perbandingan Substitusi Slag pada Semen dan Pasir pada Campuran Beton Mutu K-225 pada PT Imip Kabupaten Morowali Provinsi Sulawesi Tengah

Kawasan industri yang dibangun oleh PT Indonesia Morowali Industrial Park (IMIP) merupakan kawasan industri terpadu berbasis pada pengelolaan nikel yang juga berisi industri turunannya yang lain yaitu stainless steel. Beton merupakan bahan bangunan yang banyak digunakan dalam membangun struktur kerja di Indonesia karena banyaknya manfaat yang diberikan seperti bahan penyusunnya mudah didapat, mudah dipasang, mampu membawa beban berat, tahan terhadap suhu tinggi, dan biaya pemeliharaan. Berbagai upaya telah dilakukan untuk membuat semen. Upaya tersebut dilakukan terhadap persyaratan pemanfaatan slag dari PT Indonesia Morowali Industrial Park. Kemudian dilanjutkan dengan mengetahui perbandingan kuat tekan pada pengolahan limbah terak (slag) dengan mensubstitusi pada semen dan pasir, pada substitusi ke semen kuat tekan tertinggi berada pada substitusi terak 15% yaitu mencapai kuat tekan 24,295 MPa atau 25,34% lebih tinggi dibanding beton normal dan akan menurun kuat tekannya ketika mendapatkan substitusi lebih dari 15% sedangkan pada substitusi ke pasir akan mendapatkan kuat tekan kuat tekan tertinggi pada substitusi ke 30%, yaitu mencapai 28,956 MPa atau 49,385 lebih tinggi dibandingkan beton normal. Pada penggunaan substitusi slag ke pasir akan bertambah kuat tekannya apabila substitusi yang digunakan lebih tinggi. Jadi penggunaan slag sebagai substitusi semen dan pasir pada beton k-225 sebaiknya digunakan pada substitusi ke pasir sehingga penggunaan limbah slag lebih banyak dan memperoleh kuat tekan yang tinggi

Effect of Chlorhexidine on Nanoleakage and Bond Durability of Two Adhesives to Dentin: An In Vitro Study

Abstract Aim: This study aimed to investigate the effect of chlorhexidine (CHX) on nanoleakage (NL) and dentin bond durability of two adhesives after water storage. Materials and Methods: Thirty-six extracted molars were divided into three groups and their buccal surfaces were reduced to expose flat dentin surfaces. In group 1 Single Bond Universal Adhesive (SBU) was used, in group 2 Peak universal Bond (PUB) was applied while in group 3 Chlorhexidine Gluconate Disinfecting Solution followed by Single Bond Universal Adhesive (CHX+SBU) was used. Application of resin composite restorations was performed in all three groups. For each bonding procedure, specimens were subdivided into three subgroups according to storage period (24 hours, three & six months). After storage, resin-dentin slabs were obtained, immersed in silver nitrate and then photo developed. NL was evaluated with scanning electron microscopy. Data were explored for normality using Kolmogorov-Smirnov and Shapiro-Wilk tests and showed parametric distribution. One-way ANOVA followed by Tukey post hoc test was used to compare between more than two groups in non-related samples. Repeated measure ANOVA test was used to compare between more than two groups in related samples. Paired sample t-test was used to compare between two groups in related samples. Two-way ANOVA was used to test the interaction between different variables. The significance level was set at P ≤ 0.05. Statistical analysis was performed with IBM® SPSS® Statistics Version 20 for Windows. Results: No statistically significant difference was detected between (SBU), (PUB) and (CHX+SBU) at 24 hours. For stored specimens, there was no statistically significant difference between (SBU) and (PUB), but a statistically significant difference occurred between both of them and (CHX+SBU). Conclusions: Chlorhexidine containing universal adhesive suppressed the occurrence of nanoleakage at the interface, while chlorhexidine as a therapeutic primer had an adverse effect. Water storage negatively affected bond durability of chlorhexidine containing and free universal adhesives by showing more nanoleakage at the interface. Keywords: Chlorhexidine; dentin bonding; nanolakage

Saudi SCD patients’ symptoms and quality of life relative to the number of ED visits

Background Individuals living with sickle cell disease (SCD) have significantly increased emergency department (ED) use compared to the general population. In Saudi Arabia, health care is free for all individuals and therefore has no bearing on increased ED visits. However, little is known about the relationship between quality of life (QoL) and frequency of acute care utilization in this patient population. Methods A cross-sectional study was conducted on 366 patients with SCD who attended the outpatient department at King Fahad Hospital, Hofuf, Saudi Arabia. Data were collected through self-administered surveys, which included: demographics, SCD-related ED visits, clinical issues, and QoL levels. We assessed the ED use by asking for the number of SCD-related ED visits within a 6-month period. Results The self-report survey of ED visits was completed by 308 SCD patients. The median number of SCD-related ED visits within a 6-month time period (IQR) was four (2-7 visits). According to the unadjusted negative binomial model, the rate of SCD-related ED visits increased by (46, 39.3, 40, and 53.5 %) for patients with fever, skin redness with itching, swelling, and blood transfusion, respectively. Poor QoL tends to increase the rate of SCD-related ED visits. Well education and poor general health positively influenced the rate of SCD-related ED visits. Well education tends to increase the rate of SCD-related ED visits by 50.2 %. The rate of SCD-related ED visits decreased by 1.4 % for every point increase in general health. Conclusion Saudi patients with sickle cell disease reported a wide range of SCD-related ED visits. It was estimated that six of 10 SCD patients had at least three ED visits within a 6-month period. Well education and poor general health resulted in an increase in the rate of SCD-related ED visits

Studi Kelayakan Finansial Pada Proyek Pembangunan Kawasan Pasar Terpadu Blimbing Kota Malang

Sebagai kota terbesar kedua setelah Surabaya, banyak pembangunan terjadi di Kota Malang seperti pembangunan hotel, apartemen, mall, dsb. Akan tetapi permasalahan yang timbul adalah apakah pembangunan yang ada tersebut sudah sesuai dengan analisa kelayakan yang ada. Oleh karena itu diperlukan adanya penelitian dan pengkajian yang seksama dan sistematis untuk menghindari keterlanjuran dalam menanam modal. Tujuan penulisan skripsi ini adalah untuk mengetahui kelayakan finansial pada proyek pembangunan Kawasan Pasar Terpadu Blimbing Kota Malang. Studi kelayakan finansial adalah penelitian tentang layak atau tidaknya suatu proyek (biasanya merupakan proyek investasi) dilaksanakan. Pertama-tama dilakukan penyusunan rencana cash flow proyek dari data-data yang ada. Kemudian dilakukan analisa kelayakan proyek dari segi finansialnya menggunakan metode Net Present Value (NPV), Internal Rate Return (IRR), Benefit Cost Ratio (BCR), dan Payback Period (PP). Lalu, dilakukan analisis sensitivitas jika terjadi kenaikan biaya dan kenaikan manfaat masing-masing sebesar 10%, 15%, 20%, 25%, dan 30%. Dari hasil analisa uji kelayakan finansial dengan metode NPV, BCR, IRR, dan PP menggunakan suku bunga 7.5% pada kondisi normal, maka proyek Pembangunan Kawasan Pasar Terpadu Blimbing Kota Malang layak untuk beroperasi. Diperoleh nilai positif dari NPV sebesar Rp. 65,345,570,925, nilai >1 dari BCR sebesar 1.3791, dan nilai IRR > suku bunga 7.5% (MARR) yaitu sebesar 11,96218%. Dari uji sensitivitas suku bunga 7.5% dengan metode NPV, BCR, IRR proyek Pembangunan Kawasan Pasar Terpadu Blimbing Kota Malang layak untuk beroperasi. Diperoleh nilai positif dari NPV sebesar Rp. 109,666,153,926 jika terjadi kenaikan biaya dan kenaikan manfaat sebesar 10%, begitu juga nilai BCR > 1 sebesar 1,3734, dan nilai IRR > suku bunga 7.5% (MARR) sebesar 13,68678%. Untuk perhitungan yang selanjutnya dengan sensitivitas sebesar 15%, 20%, 25%, dan 30% juga didapatkan hasil yang sama yaitu proyek Pembangunan Kawasan Pasar Terpadu Blimbing Kota Malang layak untuk dilaksanakan. Waktu pengembalian investasi (Payback Period) dengan menggunakan metode Simple Payback Period yaitu selama 7 tahun 1 bulan 7 hari terjadi pada tahun 2017. Dengan menggunakan metode Discounted Payback Period waktu yang diperlukan adalah 10 tahun 8 bulan 1 hari pada tahun 202

A robust control design approach for altitude control and trajectory tracking of a quadrotor

Introduction. Unmanned aerial vehicles as quadcopters, twin rotors, fixed-wing crafts, and helicopters are being used in many applications these days. Control approaches applied on the quadrotor after decoupling the model or separate altitude control and trajectory tracking have been reported in the literature. A robust linear H∞ controller has been designed for both altitude control and circular trajectory tracking at the desired altitude. Problem. The ability of the quadrotor system to hover at a certain height and track any desired trajectory makes their use in many industrial applications in both military and civil applications. Once a controller has been designed, it may not be able to maintain the desired performance in practical scenarios, i.e. in presence of wind gusts. Originality. This work presents the control strategy to ensure both altitude control and trajectory tracking using a single controller. Purpose. However, there is a need for a single controller that ensures both altitude control and trajectory tracking. Novelty. This paper presents a robust H∞ control for altitude control and trajectory tracking for a six degree of freedom of unmanned aerial vehicles quadrotor. Methodology. Multi input multi output robust H∞ controller has been proposed for the quadrotor for altitude control and tracking the desired reference. For the controller validation, a simulation environment is developed in which a 3D trajectory is tracked by the proposed control methodology. Results. Simulation results depict that the controller is efficient enough to achieve the desired objective at minimal control efforts. Practical value. To verify that the proposed approach is able to ensure stability, altitude control, and trajectory tracking under practical situations, the performance of the proposed control is tested in presence of wind gusts. The ability of the controller to cater to the disturbances within fractions of seconds and maintaining both transient and steady-state performance proves the effectiveness of the controller.Вступ. Безпілотні літальні апарати, такі як квадрокоптери, двороторні апарати, апарати з нерухомими крилами та гелікоптери сьогодні використовуються у багатьох сферах застосування. У літературі повідомляється про підходи до керування, застосовані на квадрокоптері після від’єднання моделі або окремого контролю висоти та відстеження траєкторії. Надійний лінійний регулятор H∞ був розроблений як для контролю висоти, так і для відстеження кругової траєкторії на потрібній висоті. Проблема. Здатність квадрокоптерної системи зависати на певній висоті та відстежувати будь-яку бажану траєкторію робить їх застосування можливим у багатьох сферах як у військових, так і в цивільних цілях. Розроблений контролер може не підтримувати бажані характеристики у реальних умовах, тобто за наявності поривів вітру. Оригінальність. У цій роботі представлена стратегія керування, яка забезпечує як контроль висоти, так і відстеження траєкторії за допомогою одного контролера. Мета. Однак існує потреба в єдиному контролері, який забезпечує як контроль висоти, так і відстеження траєкторії. Новизна. У цій статті представлено надійний регулятор H∞ для контролю висоти та відстеження траєкторії для шести ступенів свободи безпілотних літальних апаратів. Методологія. Для квадрокоптера запропоновано багатовхідний багатовихідний надійний контролер H∞ для контролю висоти та відстеження бажаного курсу. Для перевірки контролера розробляється середовище моделювання, в якому тривимірна траєкторія відстежується за запропонованою методологією керування. Результати. Результати моделювання показують, що контролер є досить ефективним для досягнення бажаної мети при мінімальних зусиллях контролю. Практична цінність. Щоб переконатися, що запропонований підхід здатний забезпечити стабільність, контроль висоти та відстеження траєкторії в реальних ситуаціях, параметри запропонованого контролю перевіряються за наявності поривів вітру. Здатність контролера усувати порушення протягом кількох секунд і підтримувати як перехідні, так і стабільні показники доводить ефективність контролера

Catalytic Performance of Calcium-Lanthanum co-doped Ceria (Ce0.85-xLa0.15CaxO2-δ) in Partial Oxidation of Methane

In this study, Ce0.85-xLa0.15CaxO2-δ was synthesized using sol-gel combustion method and appliedfor partial oxidation of methane (POM). The physicochemical properties of catalyst were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and thermogravimetric analysis (TGA). Material shows a pure cubical structure and is highly stable up to 850 °C. The performance testing indicated the conversion of CH4 is 65% and selectivity of H2 and CO are 28% and 8%, respectively. The performance indicated the catalyst has a potential to be used for partial oxidation of methane on a larger scale. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Ergogenic, anti-diabetic and antioxidant attributes of selected Malaysian herbs: characterisation of flavonoids and correlation of functional activities

In the present work, aqueous ethanolic (60% ethanol) extracts from selected Malaysian herbs including Murraya koenigii L. Spreng, Lawsonia inermis L., Cosmos caudatus Kunth, Piper betle L., and P. sarmentosum Roxb. were evaluated for their ergogenic, anti-diabetic and antioxidant potentials. Results showed that the analysed herbs had ergogenic property and were able to activate 5'AMP-activated protein kinase (AMPK) in a concentration dependant manner. The highest AMPK activation was exhibited by M. koenigii extract which showed no significant (p > 0.05) difference with green tea (positive control). For anti-diabetic potential, the highest α-glucosidase inhibition was exhibited by M. koenigii extract with IC50 of 43.35 ± 7.5 μg/mL, which was higher than acarbose (positive control). The determinations of free radical scavenging activity and total phenolics content (TPC) indicated that the analysed herbs had good antioxidant activity. However, C. caudatus extract showed superior antioxidant activity with IC50 against free radical and TPC of 21.12 ± 3.20 μg/mL and 221.61 ± 7.49 mg GAE/g, respectively. RP-HPLC analysis established the presence of flavonoids in the herbs wherein L. inermis contained the highest flavonoid (catechin, epicatechin, naringin and rutin) content (668.87 mg/kg of extract). Correlations between the analyses were conducted, and revealed incoherent trends. Overall, M. koenigii was noted to be the most potent herb for enhancement of AMPK activity and α-glucosidase inhibition but exhibited moderate antioxidant activity. These results revealed that the selected herbs could be potential sources of natural ergogenic and anti-diabetic/antioxidant agents due to their rich profile of phenolics. Further analysis in vivo should be carried out to further elucidate the mechanism of actions of these herbs as ergogenic aids and anti-diabetic/antioxidant agents

Risk assessment for the spread of Serratia marcescens within dental-unit waterline systems using Vermamoeba vermiformis

Vermamoeba vermiformis is associated with the biofilm ecology of dental-unit waterlines (DUWLs). This study investigated whether V. vermiformis is able to act as a vector for potentially pathogenic bacteria and so aid their dispersal within DUWL systems. Clinical dental water was initially examined for Legionella species by inoculating it onto Legionella selective-medium plates. The molecular identity/profile of the glassy colonies obtained indicated none of these isolates were Legionella species. During this work bacterial colonies were identified as a non-pigmented Serratia marcescens. As the water was from a clinical DUWL which had been treated with Alpron™ this prompted the question as to whether S. marcescens had developed resistance to the biocide. Exposure to Alpron™ indicated that this dental biocide was effective, under laboratory conditions, against S. marcescens at up to 1x108 colony forming units/millilitre (cfu/ml). V. vermiformis was cultured for eight weeks on cells of S. marcescens and Escherichia coli. Subsequent electron microscopy showed that V. vermiformis grew equally well on S. marcescens and E. coli (p = 0.0001). Failure to detect the presence of S. marcescens within the encysted amoebae suggests that V. vermiformis is unlikely to act as a vector supporting the growth of this newly isolated, nosocomial bacterium

Mimo antenna system for modern 5g handheld devices with healthcare and high rate delivery

In this work, a new prototype of the eight-element MIMO antenna system for 5G communications, internet of things, and networks has been proposed. This system is based on an H-shaped monopole antenna system that offers 200 MHz bandwidth ranges between 3.4-3.6 GHz, and the isolation between any two elements is well below -12 dB without using any decoupling structure. The proposed system is designed on a commercially available 0.8 mm-thick FR4 substrate. One side of the chassis is used to place the radiating elements, while the copper from the other side is being removed to avoid short-circuiting with other components and devices. This also enables space for other systems, sub-systems, and components. A prototype is fabricated and excellent agreement is observed between the experimental and the computed results. It was found that ECC is 0.2 for any two radiating elements which is consistent with the desirable standards, and channel capacity is 38 bps/Hz which is 2.9 times higher than 4 x 4 MIMO configuration. In addition, single hand mode and dual hand mode analysis are conducted to understand the operation of the system under such operations and to identify losses and/or changes in the key performance parameters. Based on the results, the proposed antenna system will find its applications in modern 5G handheld devices and internet of things with healthcare and high rate delivery. Besides that, its design simplicity will make it applicable for mass production to be used in industrial demands