Puisi: Salahkah Teknologi dan Internet?

Dahulu, era 90-an

Aku masih di bangku sekolah

Seringkali disajikan dengan kata-kata berbunyi…

“Maklumat di hujung jari”

“Langit terbuka ,bersediakah kita?”

Entah apakah itu?

Zaman itu, yang kaya saja mampu memiliki telefon bimbit dan komputer…

Dahulu, awal tahun 2000

Internet ‘dial up’ 1515 yang mahal tapi perlahan diperkenalkan TM

Nokia 3310 mula menggegar tanahairku

Zaman itu, ramai orang mampu memilikinya

Hari ini, teknologi itu semakin berkembang canggih

Telefon bimbit menjadi telefon pintar

Komputer menjadi ‘notebook’ malah ‘ultrabook’

Hari ini, semua orang memiliki teknologi ini

Namun, sayang seribu kali sayang

Nilai kemanusiaan semakin hilang

Budi bahasa kian pudar

Fitnah dan tohmahan berleluasa

Benarkah salah teknologi dan internet?

Adakah kita, manusia kini dikuasai oleh teknologi dan internet?

Bukankah manusia yang mencipta teknologi ini?

Mengapa kita pula yang hilang kemanusiaan?

Ditulis oleh;

Siti Sara binti Rais

Introduction to IPv6

Size of IPv4 is 32-bits only, while IPv6 is 128-bits and it is represented in hexadecimal numbers in the form of X.X.X.X.X.X.X.X which X consists of 16-bit value. Example expression of IPv6 is 2000:0000:1234:ABCD:0000:0000:FACE:00006. This can be written as 2000:0:1234:ABCD:0:0:FACE:0006 or simplified to 2000::1234:ABCD:::FACE:6. If we find the address is 2000::A, it is also can be written as 2000:0:0:0:0:0:0:000A.

            Let’s take a look at this example of CIDR X:X:X:X:X:X:X:X/64. It means that the network is 64-bit, and we can calculate like Figure 1, and hence we get N.N.N.N.H.H.H.H. IPv6 does not have broadcast and network address translation (NAT). However, similar to IPv4, IPv6 has unicast and multicast. IPv6 is faster because of no broadcast. It can access anywhere, and everyone gets public IP. The differences between IPv4 and IPv6 are summarized in Table 1. We will discuss further the range of global unicast, link-local and multicast in the next volume.

Figure 1 CIDR in IPv6

Table 1 IPv4 vs IPv6

IPv4	IPv6
32-bit (decimal)	128-bit (hexadecimal)
Public IP	Global unicast 2000::/3
Private IP	Link local FE80::/10
Loopback 127.0.0.0 => 127.255.255.255	::1
Multicast 224-239	Multicast FF00::/8

IPv6 can be anycast i.e. one to nearest. Same IPv6 can be assigned to many hosts. Refer to the Figure 2, if we are in Malaysia and we do not have the server in Malaysia, we can anycast to the nearest, and it is Singapore server.

Figure 2 IPv6 anycast

Reference: CCNAX Training Materials

Written by SIti Sara Rais

Living for Work. Is It Worth It?

image source: accolo.com

Written by Nur Idawati Md Enzai

Long gone the days where a normal job revolves around 9-5 working time. Constant availability for communication, no thanks to Internet, has made the situation becomes worse. In the good old days, if you are on leave, you really could rest and don’t have to think about work. As technology has enabled us to become contactable 24-7, our bosses and colleagues could endlessly shove job after job under our very nose day and night. This could seriously affect the work life balance negatively.

Most European countries have been seriously implementing healthy work-life balance after realizing its importance. Australia and New Zealand have also jumped into the bandwagon by giving a particular attention on the work-life balance. Shorter working weeks and hours have been adopted as it is believed to help the staffs wellbeing and happiness [1]. Fun fact, even though working hours have been shortened, these countries still thrive economically. Having experienced living in Australia for a few years, I personally witnessed most Australians working really hard during the day, resting with family and friends at night, spending time with family and friends during weekends. Even the shopping malls are closed early during the weekends. A friend’s husband was told off by his boss for working on a weekend. “Don’t you have a family?” his boss asked. A university official even jokingly told the graduate students, “I don’t want to see you Asian scholars at the university on weekends.”

Asian countries are especially guilty when it comes to working long hours. Japan has always been known for long working hours and little to none vacation. True, it is a developed country, and yet the suicide rates are among the highest. Cases of death due to overwork has become quite common as well. Therefore, the government of Japan has been seriously looking into this problem, even though back in the 70s and 80s there was apparent denial that death could be caused by overwork. However, the relationship between overwork and death has been accepted by Japanese corporate lawyers and government officials [2].

I believe that the reason Asian countries tend to have more working hours, could be due to culture of saving face and hierarchy. Leaving early while the others are still at work may make an Asian feeling guilty even though he/she has finished work.  Asians are generally taught to keep their opinions to themselves to avoid conflict, compared to a Westerner who typically doesn’t care what the others think. I remember, a friend from China once told me that on Chinese New Year, some of them don’t even go back to their hometown. Chinese New Year which is supposed to be their number one celebration is not even in their priorities. It makes me afraid to imagine their working style.   

Being citizens of a Muslim majority country, Malaysian Muslims should know better that this worldly life is not the only life to be encountered. Indeed, Islam teaches us to work diligently in order to earn halal income and support the family. But not to the extent of neglecting family, friends and social responsibilities.

Surah Al-An’am verse 96 clearly indicates: “He causes the dawn to break; and He has made the night for rest, and the sun and the moon for reckoning; this is an arrangement of the Mighty, the Knowing.”

Benefits of good work life balance include: increase in productivity and motivation, reducing truancy, as well as gaining loyalty from staffs. The risks for physical and mental health can also be minimized [3].  Of course, long working hours are unavoidable especially for certain sectors such as healthcare, technical support and security. But for normal regular jobs, efficiency and common sense are the key. For instance, simple documentation works could definitely wait till morning. There's no need to discuss about work after working hours if it is not urgent. Working long hours should be the exception, not the rule. It’s about time that number of working hours should not dictate productivity; rather flexibility and ample time for family, friends and other self-improvement activities must be encouraged. This may sound easier said than done, but it is not impossible. Start with yourself, be an advocate for work life balance by being an exemplary employee and respect others' private time. Insya Allah the positivity can be spread and the others will follow suit.

[1].  https://thriveglobal.com/stories/work-life-balance-how-do-different-countries-approach-the-working-day/

[2].  https://apjjf.org/-Samuel-J--Timinsky/5283/article.pdf

[3].https://www.hrzone.com/community/blogs/valeriemanilarecruitment/offering-work-life-balance-to-improve-productivity

Esport FKE: Mobile Legends dan Counter Strike Global Offensives (CSGO)

Oleh: Mohd Amir Hamzah Ab. Ghani, Dr. Ilham Rustam, Fadhli Dzul Hilmi Mohd Fauzi, Abdul Hafiz Kassim, Dr Mohamad Yusof Mat Zin.

Hari sukan UiTM Cawangan Terengganu (UiTMCT) yang dianjurkan bersama kelab pensyarah Fakulti Kejuruteraan Elektrik (FKE), Kelab EESA (Electrical Engineering Student Association) dan unit Hal Ehwal Pelajar (HEP) pada 10 October sehingga 19 October 2019 pertama kali mempertandingkan sukan elektronik atau lebih dikenali sebagai esport. Sukan yang dipertandingkan kali ini hanya dua sahaja iaitu Mobile Legend (ML) dan Counter Strike Global Offensive (CSGO). Sukan ML bermula pada 15 October 2019 pada hari Selasa manakala CSGO berlangsung selama 2 hari iaitu pada 18 October dan 19 October 2019.

Sukan ML yang berlangsung mendapat penyertaan seramai 120 orang iaitu sebanyak 24 kumpulan daripada pelajar UiTM Cawangan Terengganu Kampus Dungun, Kampus Kuala Terengganu, Kampus Bukit Besi  dan juga pelajar  Sekolah Menengah Kebangsaan Tengku Intan Zaharah. Pengurus acara diketuai oleh Mohd Amir Hamzah Ab. Ghani dan dibantu oleh pelajar FKE yang juga ahli EESA seramai 12 orang. Para peserta mula berkumpul di Dewan Aspirasi (DA) sejak dari pukul 7.30 pagi dan taklimat bermula pada 8.30 pagi kerana memberi laluan kepada perasmian Hari Sukan Negara dan pelepasan atlit lumba basikal Weather The Storm yang berlangsung pada hari yang sama.

Perlawanan peringkat kumpulan pada sesi pagi bermula jam 9 pagi berlangsung serentak sebanyak 8 perlawanan dan dipertontonkan di skrin besar DA menerusi projektor. Manakala perlawanan separuh akhir dan akhir berlangsung pada sesi petang bermula jam 2 petang. Perlawanan akhir diantara pasukan Team Joki dan Team Public dimana kedua-dua pasukan adalah wakil daripada pelajar UiTMCT Kampus Dungun dimenangi oleh pasukan Team Public. Johan membawa pulang pingat Emas, sijil dan juga hadiah wang tunai. Pingat Perak dimenangi oleh pasukan Team Joki dan Pingat Gangsa dimenangi oleh pasukan Google.

Sukan CSGO pula berlangsung di Makmal blok 14b2 dan 14b3 pada hari Jumaat dan Sabtu. CSGO mendapat penyertaan sebanyak 12 kumpulan daripada pelajar UiTMCT Kampus Dungun, Kampus Bukit Besi dan Kampus Kuala Terengganu. Jumlah penyertaan seramai 60 peserta dimana 1 kumpulan hanya dibenarkan 5 peserta sahaja. Pengurus acara diketuai oleh Dr.Ilham Rustam dan dibantu oleh Mohd Amir Hamzah Ab. Ghani serta urusetia pelajar EESA seramai 10 orang.

Perlawanan peringkat kumpulan berlangsung pada hari pertama bermula jam 8.30 pagi untuk sesi taklimat dan 9 pagi sehingga 12.30 petang untuk memberi laluan solat Jumaat. Perlawanan bersambung pada jam 3 petang dan tamat jam 6 petang. Hari kedua bermula dengan masalah teknikal dimana perlawanan separuh akhir yang dijadualkan berlangsung jam 9 pagi terpaksa di tunda ke sesi petang pada jam 2. Ketiadaan elektrik disebabkan oleh penyelenggaraan menganggu susun atur perlawanan sehinggakan perlawanan akhir terpaksa berlangsung sehingga jam 7 malam. Perlawanan akhir di antara pasukan Rodong, wakil dari UiTMCT Kampus Dungun dengan pasukan Azure, wakil dari UiTMCT Kampus Kuala Terengganu. Johan dimenangi oleh pasukan Azure dan membawa pulang pingat Emas, sijil dan wang tunai. Pingat Perak dimenangi oleh pasukan Rodong dan Pingat Gangsa dimenangi oleh pasukan Glorious Death.

The Untold Story in the Management of Diabetes Mellitus

Written by: Dr. Nur Syukriah Ab Rahman

Diabetes mellitus (DM) is one of the most important metabolic disease that hit the globe in the present millennium. It has been listed as one of the five leading cause of deaths and approximately six death per minute are associated to DM complications [1]. The report from National Health and Morbidity Surveys shown that there is an increasing trend in the recorded prevalence of DM for the past decades and surprisingly the overall prevalence of DM has been increased by more than doubled from 1996 to 2015 in Malaysia [2].

The earliest history recorded in the treatments of DM involved the use of plants. Metformin is one of the oral diabetic drug that is widely prescribed by the medical practitioner nowadays which is originated from the use of Galega officinalis (G. officinalis) Linn as herbal medicine in primitive Europe [3]. G. officinalis is a perennial herb with blue, white or purple flowers which is commonly found in most temperate regions and grows over three feet high.

Herbal medicine is one of the subcategories of complementary and alternative medicinal (CAM) therapies. Most of the people favor CAM over conventional therapies due to unsatisfied outcomes such as adverse side effects and higher treatment cost. Synacinn^TM  is a polyherbal formulations that consist of five herbal medicine including Cinnamomun zeylanicum, Curcuma xanthorrhiza, Syzygium polyanthum, Orthosiphon stamineus and Andrographis paniculata and has been standardized against catechin, curcumin, gallic acid, rosmarinic acid and andrographolide respectively. It is believed that each herbal present in Synacinn^TM could act through intelligent network that could produce synergistic effects to remediate DM conditions. In addition, the existing literatures and testimonials suggest promising venue for Synacinn^TM to be scientifically validated and developed as an alternative drug in the management of DM.

The scientific research on the development of Synacinn^TM as herbal medicine in the management of DM is still in progress and a group of researchers from UMT and UTM have put their blood and tears on this development. As for now, Synacinn^TM is already available on the market for example Shoppe, Lazada or can be directly purchased from NatureMedic Laboratories Sdn Bhd. It is hoped that we one fine day we found the cure for this disease.

References:

[1] Li, H., Wu, X., Davey, A. K., & Wang, J. (2011). Antihyperglycemic Effects of Baicalin on Streptozotocin–Nicotinamide Induced Diabetic Rats. Phytotherapy Research, 25(2), 189–194.

[2] Tee, E.-S., & Yap, R. W. K. (2017). Type 2 Diabetes Mellitus in Malaysia: Current Trends and Risk Factors. European Journal of Clinical Nutrition, 71(7), 844–849. https://doi.org/10.1038/ejcn.2017.44

[3] Bailey, C. J., & Day, C. (1989). Traditional Plant Medicines as Treatments for Diabetes. Diabetes Care, 12(8), 553–564. https://doi.org/10.2337/diacare.12.8.553

Mental Health Awareness

Written by Fathiah Zakaria

Mental illness has become one of the prevailing health problem nowadays. Mental illness happens to people from all walks of lives, professionals, students, parents and children. Among prevention and intervention methods available are counselling, therapeutic assessment (physiatrist), circle time and support group. DSM-5 is a Diagnostic and Statistical Manual of Mental Disorders, published by the American Psychiatric Association (APA). DSM-5 serves as the guidelines for psychiatric diagnosis and also treatment recommendations. Among types of mental disorder listed in DSM-5 are Anxiety Disorder, Autism Spectrum, Personality Disorder, Major Depressive Disorder, Social Communication Disorder and etc. [1]. In developed countries like United States, the treatment cost for mental disorder is covered by medical insurance.

There are numbers of Government entities, NGO and private practices that provide services related to mental health in Malaysia such as MENTARI Malaysia, Mental Illness Awareness & Support Association (MIASA), Relate Malaysia, Malaysian Mental Health Association and etc. In fact, most of the Government entities provides in-house counsellor and psychologist. If you feel you are having unstable emotional, changing in mental state condition, there is no harm of finding professional help. Counselling would be one of effective methods to deal with this condition. Counselling provides a safe space to talk about thoughts and feelings, subjected to counsellor’s ethics and confidentiality. It allows someone to talk with a professional who can help to work on specific issues that they are facing with. Try to find registered counsellor with notation (KB,PA) – “Kaunselor Berdaftar dan Perakuan Amalan” after their name, because they are registered with Lembaga Kaunselor Malaysia [2]. In the condition where further treatment and medical assessment is needed, counsellor will refer the clients to the psychiatrist.

World Health Organization (WHO) defined mental health as “a state of well-being in which every individual realizes his or her own potential, can cope with the normal stresses of life, can work productively and fruitfully, and is able to make a contribution to her or his community” [3]. Let’s check on our mental state condition. Positive mental well-being results in blissful community and prosperous country. Remember that “loving ourselves works miracle in our lives”.

[1] “DSM-5” Accessed on: 1 November, 2019. [Online]. Available: https://www.psychiatry.org/psychiatrists/practice/dsm/educational-resources/dsm-5-fact-sheets

[2] “Lembaga Kaunselor Malaysia” Accessed on: 1 November, 2019. [Online]. Available: https://www.lkm.gov.my/

[3] “Mental Illness Definition” Accessed on: 1 November, 2019. [Online]. Available: https://relate.com.my/

Physics Law in washing machine design

Written by Siti Aishah Che Kar and Syila Izawana Ismail

Nowadays, washing machine is one of the must-have household equipments. But how does the smart machine spin and drain all the water from our clothes? Or what is actually happening during the spinning process? Here comes the scientific explanation. Centrifuge is the word or term that is used to describe the whole process. You can do a very simple experiment at home to understand the centrifuge phenomenon. Take wet clothes and turn the clothes while holding them. You can see the excess water sparking out from the wet clothes. Actually the clothes spin in circle because you force it but the water trapped in clothes retains to move in straight line. Thus the water will fly out from the wet clothes and automatically the clothes will be drier than before. [1]

Thus this concept is applied in the washing machine process. After the rinsing process, the washing machine will be in drain mode automatically where a pump is used to drain all the excess water. Then, the spin mode will take over. In top loader washing machine, the agitator which is a large plastic at the bottom of the drum will spin while in the front loader washing machine, the drum itself will spin. The drum is actually like a big basin that holds our clothes. Usually each washing machine contains two drums which are the inner drum and the outer drum. The clothes are forced to move in circle because the inner drum is spinning but the excess water in clothes still goes straight, turning into water drop. The water drop is small enough to pass through the drum’s tiny holes into the outer drum. This phenomenon is actually relevant to the Isaac’s most famous laws of motion. The First Law of motion states, “A body at rest will remain at rest, and a body in motion will remain in motion unless it is acted upon by an external force.” This simply means that things cannot start, stop, or change direction all by themselves. It takes some force acting on them from the outside to cause such a change [2].

The centrifuge concept is well used in many applications especially in science laboratory as centrifuges to separate things like component in blood or any substances in liquid form. The blood sample will be spin at high speed using centrifuge to separate the blood cell such as plasma and red blood cells. NASA also uses centrifuge concept for testing their astronauts and pilots in psychology test by using human centrifuges to test whether the astronauts are fit for the space ship [3].

References:

[1] http://www.explainthatstuff.com/centrifuges.html

[2] https://www.livescience.com/46558-laws-of-motion.html

[3] https://en.wikipedia.org/wiki/Astronaut_training

Kembara Ilmu bersama Ustaz Abdul Somad

Oleh : Wan Ahmad Khusairi Wan Chek, Fadhli Dzul Hilmi Mohd Fauzi, Dr. Baktiar Musa (Fakulti Kejuruteraan Elektrik), En Tajulurus Mohammad ( Fakulti Pengurusan Hotel)

15 Febuari 2019 merupakan hari pertama kami berempat memulakan satu ekspedisi bermotosikal bagi mengikuti perjalanan penceramah terkenal dari seberang iaitu Ustaz Abdul Somad (UAS) yang menjelajah Malaysia menerusi siri ceramah beliau. Memandangkan ceramah beliau bermula di negeri Kelantan, maka destinasi pertama konvoi kami menuju ke negeri Cik Siti Wan Kembang. Konvoi biasanya sinonim dengan kembara berkumpulan yang menggunakan motorsikal berkuasa tinggi, namun kami sedikit berbeza kerana menggunakan motorsikal dari kategori moped.

Tepat jam 830 pagi, kami mula berkumpul di perkarangan stesen minyak Petronas (hadapan SM Sains Dungun) untuk acara pelepasan. Walaupun hanya berempat, namun semangat berkonvoi tetap membara dan berkobar-kobar. Bagi Wan dan Fadhli, ini merupakan pengalaman konvoi pertama yang disertai. Setelah selesai membaca doa bagi memulakan perjalanan, maka deruan enjin motoraikal mula bergema dan perjalanan konvoi kami pun bermula.

Perhentian pertama kami adalah di sekitar daerah Marang kerana kami semua ‘skip’ makan pagi bersama keluarga. Chief de Mission kami, En Tajul mencadangkan untuk berhenti menjamu selera di kedai nasi dagang 30 tahun. Saya akui itu merupakan pertama kali saya mengetahui akan kewujudan kedai nasi dagang tersebut. Menarik nama panggilan kedai it’s. Sesudah selesai menjamu selera, konvoi diteruskan.

Dalam jam 1.00 tengahari, kami sampai di Kuala Besut. Kami behenti sekejap untuk makan tengah hari. Kami memilih untuk makan nasi ayam di sebuah kedai yang terletak berhampiran pasar pagi Kuala Besut. Harga nasi ayam di situ agak murah dan yang penting mengenyangkan kami. Alhamdulillah, syukur.

Perjalanan direntasi dan kami sampai di rumah penginapan di Kota Bharu sekitar jam 3.30 petang. Penginapan yang di tempah oleh En Tajul agak selesa dan selamat kerana berpagar. Setelah berehat dan menyegarkan badan, kami terus bergerak menuju ke Stadium Sultan Mohamad ke - 4 untuk menyertai ceramah Ustaz Abdol Somad (UAS). Kami keluar awal kerana memang menjangkakan kesesakkan berlaku memandangkan ribuan orang yang memenuhi stadium tersebut.

Kami sampai di sekitar perkarangan agak awal, namun kawasan stadium sudah pun sangat meriah dipenuhi dengan orang ramai yang berpusu-pusu. Juga terdapat pelbagai gerai jualan. Menantikan program bermula, kami mengambil kesempatan untuk menjamu selera rerlebih dahulu. Sebaik sahaja masuk waktu Maghrib, kami semua menunaikan solat Maghrib secara berjemaah di padang stadium tersebut. Setelah selesai menunaikan solat kami bergegas mencari lokasi yang strategik untuk mendengar ceramah dari Ustaz Abdol Somad.

Usai ceramah, kami singgah untuk minum malam di sebuah kedai berhampiran Wakaf Che Yeh. Di situ, kami perbincangan tentang aturacara perjalanan untuk keesokan harinya. Mengikut jadual, destinasi UAS yang seterusnya adalah kuliah subuh di Pasir Puteh dan seterusnya di Perak. Setelah selesai  minum malam kami pun pulang ke rumah penginapan kami untuk melelapkan mata.

Systematic Guideline for Safety Assessment based on Process Information

Written by: Muhammad Firdaus Husin

In chemical engineering, one of the targets of the process design is the creation or modification of flow diagrams capable of manufacturing the desired chemical. It is also essential to consider safety aspects when designing any new process or in the case of retrofitting. As a result, several methods have been introduced for safety assessment during process design phase [1]. To date, there are lacks of guideline in selecting an appropriate method for him/her based data availability, target of assessment and budget constraints. To fill in this gap, a heuristic framework are designed for assisting users in conducting safety assessment during chemical process design.

Figure 1 shows a summary of designing framework for process safety assessment in chemical process design methods and their strategies for minimization of hazards or risks which are based on inherent safer design (ISD) keywords [2]. For all methods, the calculated index or risk values and hazards will be compared with the respective benchmark. If the value of calculated index or risk is not acceptable, four ISD keywords (minimization, substitution, moderation and simplification) are taken-over to reduce or eliminate the hazard as much as possible. Finally, the re-assessment of hazards can be performed until the index values and all hazards are at acceptable range. The frameworks shall serve as a great help for engineers to select appropriate method for safety assessment based on the availability of process information during the chemical process design. Instead of assessing the safety level of process design phase, this framework can also be used to analyse the root of the safety problems and recommend the possible solutions.

References

 [1] Khan, F. I. and Abbasi, S. A. (1998c). Techniques and methodologies for risk analysis in chemical process industries. Journal of Loss Prevention in the Process Industries, 11(4), 261-277.

[2] Kletz, T. A. (1991). Plant Design for Safety : User-friendly Approach.

Pulsed lasers: Q-switched and Mode-locked techniques

Written by: Dr Baktiar Musa, Suziana Omar, Ir. Dr. Zulzilawati Jusoh and Norizan Ahmed

This article tries to explain about our research on Q-switched and mode-locked lasers. We begin with the definition of laser first, LASER is actually an acronym for Light Amplification by Stimulated Emission of Radiation. Historically, the first laser was realized in 1960 at Hughes Research Laboratories by Theodore H. Maiman following the theoretical work by Charles Hard Townes and Arthur Leonard Schawlow [1].

In order to understand how pulsed lasers work, we need to revisit our fundamental knowledge in physics. But explaining all those fundamentals can be tiresome, so here we just focused on differentiating pulsed laser and continuous wave (CW). CW refers to a laser that is continuously pumped and continuously emits light. The emission can occur in a single resonator mode or on multiple modes. An example of CW laser is CO₂, where initially the gas is ionized to the threshold level and then by using pulse width modulation (PWM), the laser output can be controlled. For comparison, CO₂ molecules readily lase at 10.6 µm, while neodymium-based crystals (like YAG or vanadate) produce wavelengths in the range between 1047 and 1064 nm. Each laser wavelength is associated with a linewidth, which depends on several factors: the gain bandwidth of the lasing medium and the design of the optical resonator [2]. On the other hand, a pulsed laser operates in such a way that all of its energy is dumped out in a single pulse which normally lasts from picoseconds to few nanoseconds. After that the laser output goes to zero. Again, the pulse appears at the output. This switching is done by Q switch.

Two commonly used techniques employed in producing pulsed lasers are Q-switching and mode-locking. A Q-switched laser is a laser to which the technique of active or passive Q switching is applied, so that it emits energetic pulses [3]. Typical applications of such lasers are material processing (e.g. cutting, drilling, laser marking), pumping nonlinear frequency conversion devices, range finding, and remote sensing. Q-switching technique allows the production of light pulses with extremely high (gigawatt) peak power, much higher than would be produced by the same laser if it were operating in a CW mode. Using mode-locking technique, the laser output will be pulses of light of extremely short duration, on the order of picoseconds (10⁻¹² s) or femtoseconds (10⁻¹⁵ s). Here, the laser resonator contains some kind of mode locking device – either an active element (an optical modulator) or a nonlinear passive element (a saturable absorber), which causes the formation of an ultrashort pulse circulating in the laser resonator [4]. In terms of repetition rates and pulsed durations, Q-switched lasers showed lower values compared to ones produced by using mode-locking technique.  Depending on the applications, sometimes the techniques are used together to produce pulsed lasers.

For generation of pulsed laser, a passive mode-lockers are preferred due to their simpler configuration and thus far, a variety type of saturable absorber (SA) have been proposed [3-6]. Our research focused on finding and exploring new materials that are suitable as saturable absorbers. Previously, carbon materials such as carbon nanotubes (CNTs) and graphene show promising performances as saturable absorber to achieve mode-locking in fiber lasers [5, 6]. It offers characteristics such as ultrafast recovery time and capable to achieve broadband operation. Recently, numerous novel 2D materials such as topological insulators [8,9], transition metal dichalcogenide (TMD), black phosphorus, MXene, bismuthene, metal-organic frame-works, and perovskite have demonstrated broad-band optical nonlinearities [7]. The properties of these saturable absorbers will be discussed in the next article.

1.     https://en.wikipedia.org/wiki/Laser

2.     https://www.photonics.com/Articles/Lasers_Understanding_the_Basics/a25161

3.     https://www.rp-photonics.com/q_switched_lasers.html

4.     https://www.rp-photonics.com/mode_locking.html

5.     Luo Z, Liu C, Huang Y, Wu D, Wu J, Xu H, Cai Z, Lin Z, Sun L and Weng J.  IEEE Journal of Selected Topics in Quantum Electronics 20 1-8 (2014)

6.     Bao Q, Zhang H, Wang Y, Ni Z, Yan Y, Shen Z X, Loh K P and Tang D Y.  Advanced Functional Materials 19 3077-83 (2009)

Li, L., Lv, R., Chen, Z. et al. Nanoscale Res Lett 14, 59 (2019)

Colour Development of Green Coffee Bean during Batch Roasting in Fluidized Bed Roaster

(By: Mohamad Taib Miskon & Nurul ‘Uyun Ahmad)

“While enjoying a cup of an aromatic, astonishing, hot and refreshing coffee drink.”

Roasting has been one of the most important step in a coffee production as it transforms the tasteless green coffee bean into a delicious cup of Joe. It is an act of introducing an amount of heat to a batch of green coffee bean to trigger complex chemical reaction [1] as well as colour and physical change [2]. There are various types of coffee roasting methods such as using the traditional hot pan, drum roaster and fluidized bed or hot air roaster.

This article presented the colour development of green Ethiopian coffee bean during roasting in a Fresh Roast SR500 coffee roaster with Artisan Roaster Scope. Figure 1.0 depicted the colour changes of the bean over temperature progression during the roasting process. The process took about 15 minutes and it can be divided into six key stages;

Stage 1: Drying (at minutes: 0 – 2.15)

The roasting process started with the bean temperature at 33°C and it endured the drying phase for about 2.15 minutes as the beans’ colour changed from green to yellow. During this stage, the beans were absorbing heat from the hot air or also known as an endothermic process. 

Stage 2: Yellowing (at minutes: 2.15 – 6.33)

At this stage, more water was removed from the bean and the bean colour was changing from yellow to brown. The size of the bean was also expanding rapidly due to the build-up of gas pressure inside the bean [3].

Stage 3: First Crack (at minutes: 6.33 minutes)

The first crack was determined by the audible popping sound, indicating the beginning of the beans’ exothermic reaction.

Stage 4: Roast development (at minutes: 6.33-9.09)

At this stage, the beans’ flavour and sweetness started to develop [4] and the process continued for about 3 minutes.

Stage 5: Second Crack (at minutes: 9.27)

The second crack occurred at minutes of 9.27 and the heater was turned off shortly after to allow the execution of the cooling phase.

At this stage, the bean experienced the second crack whereby the oil’s bean were encapsulated to the surface of the bean. The bean produced was less acidic, smoky yet aromatic, and the authentic flavour has developed.

Stage 6: Cooling (at minutes: 9.36-15.00)

The bean must be cooled quickly to stop the roasting process.

[1]       A. N. Gloess et al., “Evidence of Different Flavour Formation Dynamics By Roasting Coffee From Different Origins: On-Line Analysis With PTR-ToF-MS,” Int. J. Mass Spectrom., vol. 365–366, pp. 324–337, 2014.

[2]       J. Daniel Bustos-Vanegas et al., “Developing Predictive Models For Determining Physical Properties of Coffee Beans During The Roasting Process Kinetic Charcoal Cooling: Computer Simulation and Technological Applications View Project Harvest Process View Project Developing Predictive Models For Determining Physical Properties Of Coffee Beans During The Roasting Process,” Ind. Crop. Prod., vol. 112, pp. 839–845, 2018.

[3]       R. Eggers and A. Pietsch, “Technology I: Roasting,” Coffee Recent Dev., pp. 90–107, 2008.

[4]       L. Poisson, I. Blank, A. Dunkel, and T. Hofmann, The Chemistry of Roasting-Decoding Flavor Formation. Elsevier Inc., 2017.