Performance Investigation of O-Ring Vacuum Membrane Distillation Module for Water Desalination

A new O-ring flat sheet membrane module design was used to investigate the performance of Vacuum Membrane Distillation (VMD) for water desalination using two commercial polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF) flat sheet hydrophobic membranes. The design of the membrane module proved its applicability for achieving a high heat transfer coefficient of the order of 103 (W/m2 K) and a high Reynolds number (Re). VMD experiments were conducted to measure the heat and mass transfer coefficients within the membrane module. The effects of the process parameters, such as the feed temperature, feed flow rate, vacuum degree, and feed concentration, on the permeate flux have been investigated. The feed temperature, feed flow rate, and vacuum degree play an important role in enhancing the performance of the VMD process; therefore, optimizing all of these parameters is the best way to achieve a high permeate flux. The PTFE membrane showed better performance than the PVDF membrane in VMD desalination. The obtained water flux is relatively high compared to that reported in the literature, reaching 43.8 and 52.6 (kg/m2 h) for PVDF and PTFE, respectively. The salt rejection of NaCl was higher than 99% for both membranes

In Silico Modelling to Assess the Electrical and Thermal Disturbance Provoked by a Metal Intracoronary Stent during Epicardial Pulsed Electric Field Ablation

[EN] Background: Pulsed Electric Field (PEF) ablation has been recently proposed to ablate cardiac ganglionic plexi (GP) aimed to treat atrial fibrillation. The effect of metal intracoronary stents in the vicinity of the ablation electrode has not been yet assessed. Methods: A 2D numerical model was developed accounting for the different tissues involved in PEF ablation with an irrigated ablation device. A coronary artery (with and without a metal intracoronary stent) was considered near the ablation source (0.25 and 1 mm separation). The 1000 V/cm threshold was used to estimate the PEF-zone¿. Results: The presence of the coronary artery (with or without stent) distorts the E-field distribution, creating hot spots (higher E-field values) in the front and rear of the artery, and cold spots (lower E-field values) on the sides of the artery. The value of the E-field inside the coronary artery is very low (~200 V/cm), and almost zero with a metal stent. Despite this distortion, thePEF-zone contour is almost identical with and without artery/stent, remaining almost completely confined within the fat layer in any case. The mentioned hot spots of E-field translate into a moderate temperature increase (<48 _C) in the area between the artery and electrode. These thermal side effects are similar for pulse intervals of 10 and 100 _s. Conclusions: The presence of a metal intracoronary stent near the ablation device during PEF ablation simply `amplifies¿ the E-field distortion already caused by the presence of the vessel. This distortion may involve moderate heating (<48 _C) in the tissue between the artery and ablation electrode without associate Background: Pulsed Electric Field (PEF) ablation has been recently proposed to ablate cardiac ganglionic plexi (GP) aimed to treat atrial fibrillation. The effect of metal intracoronary stents in the vicinity of the ablation electrode has not been yet assessed. Methods: A 2D numerical model was developed accounting for the different tissues involved in PEF ablation with an irrigated ablation device. A coronary artery (with and without a metal intracoronary stent) was considered near the ablation source (0.25 and 1 mm separation). The 1000 V/cm threshold was used to estimate the `PEF-zone¿. Results: The presence of the coronary artery (with or without stent) distorts the E-field distribution, creating hot spots (higher E-field values) in the front and rear of the artery, and cold spots (lower E-field values) on the sides of the artery. The value of the E-field inside the coronary artery is very low (~200 V/cm), and almost zero with a metal stent. Despite this distortion, the PEF-zone contour is almost identical with and without artery/stent, remaining almost completely confined within the fat layer in any case. The mentioned hot spots of E-field translate into a moderate temperature increase (<48 _C) in the area between the artery and electrode. These thermal side effects are similar for pulse intervals of 10 and 100 _s. Conclusions: The presence of a metal intracoronary stent near the ablation device during PEF ablation simply `amplifies¿ the E-field distortion already caused by the presence of the vessel. This distortion may involve moderate heating (<48 _C) in the tissue between the artery and ablation electrode without associated thermal damage. d thermal damage.This research was funded by Government of Ireland, Disruptive Technology Innovation Fund (DTIF), grant number DT20180123, and Spanish MCIN/AEI/10.13039/501100011033, grant RTI2018-094357-B-C21.González-Suárez, A.; Pérez, JJ.; O Brien, B.; Elahi, A. (2022). In Silico Modelling to Assess the Electrical and Thermal Disturbance Provoked by a Metal Intracoronary Stent during Epicardial Pulsed Electric Field Ablation. Journal of Cardiovascular Development and Disease. 9(12):1-11. https://doi.org/10.3390/jcdd912045811191

The influence of managerial communication skills on project risk management practices in the Libyan oil and gas industry

With the world’s population continuing to grow, global energy needs are growing. Hydrocarbons are the key contributors to meet these energy demands, according to the latest possible estimates. However, the oil and gas sector faces considerable risks since they are massive, complicated and technologically challenging, including many stakeholders. The article demonstrates that many oil & gas companies’ projects collapse due to inadequate risk control practices. Project risk assessment is an operative tool for development and controlling cost, time, and attaining the technical performance of the oil and gas project. Oil and gas industry is also faced with several challenges, threatening to overrun projects, expense and low-quality delivery. As a result, oil and gas projects must be completed on schedule, budget and at the highest quality; therefore, risk assessment activities are an integral aspect of the oil & gas decision-making mechanism in assessing progress or loss of oil & gas projects. In line with this need, this study objective is to recognise managerial skills in Libya’s oil & gas projects and a methodological structure for applying risk management concepts in oil & gas projects to enhance their efficiency. The paper attempted to conserve, characterise and analyse evidence for this research through a systemic literature review. This system will support project stakeholders in the planning process and help produce high-quality projects, in which time and costs are closely monitored

Selective Coronary Angiography Following Cardiac Arrest

Sudden cardiac arrest is a major cause of death predominantly caused by ventricular tachyarrhythmia in patients with coronary artery disease. Despite advancements in resuscitation care, the rate of survival after cardiac arrest remains low. There is a growing body of observational data suggesting early coronary angiography reduces delay to revascularization and may improve outcomes. Most survivors present comatose, and neurologic outcome is uncertain; therefore it is often challenging to identify patients who will benefit from early coronary angiography. Several variables and risk scores that predict a favorable neurologic outcome have been identified. The rationale and current evidence for early angiography are reviewed, and a suggested approach to the selection of patients is presented

TRANSPLANTASI KARANG BATU BERCABANG DI PERAIRAN TANJUNG PAPUTUNGAN

The formation of coral reefs is a long and complex process. The process of forming coral reefs begins with the attachment of various lime-producing biota on a hard substrate. Coral reefs take quite a long time to recover and are highly dependent on water conditions. Until now, pressures caused by human activities such as pollution from land and destructive fisheries practices have been considered a major threat to coral reefs. Efforts to overcome damage to coral reef ecosystems can be done by developing coral transplantation techniques. In response to this, the research wiil apply the method of artificial reefs from concrete blocks as a container for the installation of colonies of Acropora formosa spesies and Porites cylindrica spesies. A total of 75 branched coral colonies were transplanted in the waters of 75 branched coral colonies were transplanted in the waters of the Paputungan cape 39 colonies of branched growth forms of Acropora form and 36 colonies of branched grotwth forms of Porites cylindrica spesies were transplanted in artificial reef units. Data collection in the field in the form colonies that were successfully transplanted into artificial reef units totaling 6 units will be documented using cameras from each block taken perpendicular pictures and photographing colonies from earch artificial reef unit. The results of the shoot were then analyzed using software of the Image-J application. At the end of the observation process, it was found that the highest resistence of transplane colonies was 97.2 % where there were 35 surviving colonies and 1 dead colony out of a total of 36 colonies transplanted by Porites cylindrica spesies. Meanwhile, observations found that the lowest resistnce of transplant colonies that survived and 13 colonies that died out of a total of 39 colonies transplanted by acropora formosa spesies. Acropora formosa has a relatively fast increase compared to Porites cylindrica spesies. The highest accretion was dominated by the 18.05 mm fragment-size Acropora formosa spesies at the end of the sixth lunar observation.Keywords: Restoration, transplantation, Branching Coral, Tanjung Paputungan, North Minahasa ABSTRAKTerbentuknya terumbu karang merupakan suatu proses yang lama dan kompleks. Proses terbentuknya terumbu karang dimulai dengan penempelan berbagai biota penghasil kapur pada substrat yang keras. Terumbu karang membutuhkan waktu yang cukup lama untuk pulih kembali dan sangat tergantung dari kondisi perairan. Hingga kini, tekanan yang disebabkan oleh kegiatan manusia seperti pencemaran dari daratan dan praktek perikanan yang merusak telah dianggap sebagai ancaman utama untuk terumbu karang. Upaya penanggulangan kerusakan ekosistem terumbu karang dapat dilakukan dengan menggembangkan teknik transplantasi karang (coral transplantation). Menanggapi hal tersebut, maka dalam penelitian kali akan menerapkan metode terumbu buatan dari blok beton sebagai wadah untuk pemasangan koloni spesies Acropora formosa dan spesies Porites cylindrica. Sebanyak 75 koloni karang bercabang yang di transplantasi di perairan tanjung Paputungan 39 koloni bentuk pertumbuhan bercabang spesies Acropora formosa dan 36 koloni bentuk pertumbuhan bercabang spesies Porites cylindrica ditransplantasikan pada unit terumbu buatan. Pengambilan data dilapangan berupa Koloni yang berhasil di transplantasi ke unit terumbu buatan berjumlah 6 unit akan didokumentasikan menggunakan kamera dari tiap-tiap blok di ambil gambar tegak lurus dan memotret koloni dari masing-masing unit terumbu buatan. Hasil pemotretan tersebut selanjutnya dianalisa menggunakan sofware atau aplikasi Image-J. Akhir proses pengamatan ditemukan bahwa ketahanan koloni transplan tertinggi yaitu 97,2 % dimana terdapat 35 koloni yang bertahan hidup dan 1 koloni yang mati dari total 36 koloni yang di transplantasi spesies Porites cylindrica. Sedangkan pengamatan ditemukan bahwa ketahanan koloni transplan terendah yaitu 66,6 % dimana terdapat 26 koloni yang bertahan hidup dan 13 koloni yang mati dari total 39 koloni yang di transplantasi spesies Acropora formosa. Acropora formosa mempunyai pertambahan relatif cepat di bandingkan janis Porites cylindrica. Pertambahan paling tinggi didominasi oleh spesies Acropora formosa ukuran fragmen 18,05 mm di akhir pengamatan bulan keenam.Kata Kunci: Restorasi, Transplantasi, Karang bercabang, Tanjung Paputungan, Minahasa Utar

PENGARUH LOGAM BERAT TIMBAL TERHADAP PERTUMBUHAN ALGA Halimeda opuntia YANG DIKULTUR DALAM WADAH TERKONTROL

Heavy metal is a very dangerous pollutant waste for it cannot be destroyed (non-degradable) and over time it will accumulate in the ocean. This study aims to determine the lead content in sediment, water and algal thallus as well as to determine the algae growth that has been treated with lead. The research method used was a completely randomized design (CRD) which consisted of 3 treatments, using different treatments for each sample. The highest metal content obtained in the sediment was 5,124 ppm, in the water was 0.120 ppm, and in the algae thallus was 4,816 ppm respectively. The results showed that Halimeda opuntia algae can grow even in an environment contaminated with lead heavy metal and can become a bioremediation agent by absorbing lead heavy metal. Keywords: Halimeda opuntia, Lead Heavy Metal, Algae Culture, Bioremediation             Logam berat merupakan salah satu limbah pencemar yang sangat berbahaya karena tidak dapat dihancurkan (non degradable) dan dapat terakumulasi di perairan laut. Penelitian ini bertujuan untuk mengetahui kandungan timbal pada sedimen, air dan thallus alga yang dikultur serta mengetahui pertumbuhan alga yang telah diberi perlakuan timbal. Metode penelitian mengunakan metode Rancangan Acak Lengkap (RAL) yang terdiri dari 3 perlakuan, dengan menggunakan perlakuan yang berbeda pada tiap sampel dan kontrol. Kandungan logam tertinggi yang didapatkan pada sedimen yaitu sebesar 5,124 ppm, pada air sebesar 0,120 ppm, dan pada thallus alga sebesar 4,816 ppm. Hasil yang diperoleh yaitu alga Halimeda opuntia dapat bertumbuh walaupun dalam lingkungan yang tercemar logam berat timbal serta mampu menjadi agen bioremediasi dengan menyerap logam berat timbal. Kata kunci: Halimeda opuntia, Logam BeratTimbal, Kultur Alga, Bioremedias