Displaying publications 21 - 40 of 2561 in total

Abstract:
Sort:
  1. Zaiton Harun
    The Alur Lebey fault zone, which is paralled to part of Sungai Lebey, is exposed along the East-West Highway at km 221.5 to Kota Bharu. The outcrop is about 155 m wide on the east and 105 m wide on the west side of the road. Fault morphology can be recognised from the faceted hill spurs along the valley. The fault zone has been interpreted as a lithological contact between metavolcanic in the west and metaclastic in the east. The northern extension of the fault was interpreted as the contact between silicous pelite in the west, and chert and siliceous pelite in the east. Even though left lateral motion is exhibited within the zone, evidences of right lateral motion were also observed. On Landsat 3 image, a lineament in the direction of 355° representing the Alur Lebey fault zone could be traced for some 55 km from the East-West Highway to the middle of east Pattani River in Thailand. The outcrop at the East-West Highway comprises medium indurated mylonite containing lenses of quartz and tuff. Other than asymmetric lenses, quartz also occurs in the form of a comma, and pinch-and-swell structures. These forms of clasts are used to determine the sense of movements along the fault. In general, steeply to vertically dipping mylonite strikes towards the north. Fault planes with horizontal senses of motion cut the foliotion at an acute angle. Some of these fault planes are parallel to the foliation. There are also reverse fault planes with medium to gentle dips to the west. General motions of the fault were tOwards the east southeast. The mylonite foliation which strikes north contains evidences of both left and right lateral motions, whereas the northwest striking foliation exhibits left lateral motion. Several fault-associated folds plunging towards the north northwest, south southwest and east were observed in the fault zone. The combination of field observations and structural analysis are used to arrive at the interpretation on the history of the fault zone. Four systems of compressions (maximum principal stresses) can be deduced from the study. these are the north-northeast, east-southeast, east-southeast, and the youngest north-northeast directions. The oldest deformation is characterised by dextral movement along the mylonite zone. the zone contains asymmetric lenses of tuff and quartz striking 355° to 05°. The sinistral movement along mylonite fooliation striking 354° and 326° is the evidence of the east-southest compressive stress system. Both deformation episodes could represent aseismic faultings under fairly high confining pressure. However the recurrance of the east-southest stress system could have caused the sinistral movement along the northwest and north striking fault planes, the reverse faulting on south to southwest planes and the resulting drag folds. The dextral movement along the north and northwest planes is the youngest deformation episode. The final two episodes could represent brittle deformation resulting from the shallow position of the rock body at least along that particular fault segment.
    Zon sesar Alur Lebey yang selari dengan sebahagian Sungai Lebey, tersingkap di km 221.5 dari Kota Bharu di lebuhraya Timur-Barat. Panjang singkapan keratan di timur jalan di sekitar 155m, manakala di barat jalan pula 105m. Morfologi sesar ditunjukkan oleh barisan susuh bukit beifaset di sepanjang lembah. Di lapangan dan di peta geologi, sesar ini ditafsirkan sebagai sempadan di antara metavolkano di baratnya dan metaklas di timurnya. Lanjutannya ke utara ditafsirkan bahawa sesar tersebut memotong sepanjang sempadan di antara pelit bersilika di barat dan rijang serta pelit bersilika di timur. Sungguhpun gerakan mendatar ke kiri terpamer dalam milonit, namun pergerakan mendatar ke kanan boleh dicerap dalam zon tersebut. Dalam area Lansat 3 bertarikh 10 Januari 1979 lineamen berjurus 355° yang mewakili zon sesar Alur Lebey dapat dikesan sepanjang 55 Ian dari Lebuhraya Timur-Barat hingga ke pertengahan bahagian timur Sungai Pattani di Thailand. Singkapan sesar tersebut terdiri daripada milonit separuh terluluhawa yang mengandungi kekanta kuarza dan tuf. Selain berbentuk kekanta, kuarza juga berbentuk koma, dan ramping-dan-ampul. Klas yang berbentuk tersebut digunakan untuk menentukan hala pergerakan dalam zon sesar. Umumnya milonit menjurus ke utara dengan kemiringannya euram hingga tegak. Satah-satah sesar mendatar memo tong foliasi milonit pada sudut tirus atauJdan ada pula yang selari dengannya. Selain sesar mendatar terdapat pula sesar songsang yang kemiringannya landai hingga sederhana ke barat. Gerakan umumnya menyongsang ke timur-tenggara. Foliasi milonit yang menjurus ke utara mengandungi tanda-tanda pergerakan ke kiri dan ke kanan, manakala foliasi yang menjurus ke baratlaut mengandungi hanya pergerakan mendatar ke kiri. Sebilangan lipatan yang berkait-rapat dengan sesar menunjam ke utara-baratlaut, selatan-baratdaya dan ke arah timur dieerap di dalam zon sesar tersebut. Gabungan eerapan lapangan dan analisis struktur akhirnya sampai kepada pentafsiran sejarah canggaan yang berlaku di dalam zon sesar tersebut. Empat sistem tegasan boleh disimpulkan. Sistem tegasan maksimum (mampatan) tersebut ialah .utara-timurlaut, timur­tenggara, dan yang termuda utara-timurlaut. Canggaan tertua dicirikan oleh pergerakan dekstral di sepanjang zon milonit yang mengandungi kekanta tuf dan kuarza yang asimetri berjurus 355° hingga 05°. Pergerakan sinistral di sepanjang milonit yang berjurus 354° dan 326° merupakan bukti daripada sistem tegasan timur-tenggara. kedua-dua episod canggaan mungkin mewakili penyesaran aseismos yang berlaku dalam sekitaran tekanan mengepung yang tinggi. Namun demikian perulangan tindakan sistem tegasan timur-tenggara menyebabkan pergerakan sinistral di sepanjang satah sesar berjurus baratlaut dan utara, penyesaran songsang di atas satah berjurus selatan hingga baratdaya dan lipatan seret. Pergerakan dekstral di sepanjang satah berjurus utara dan baratdaya merupakan episod canggaan yang termuda. Dua episod yang terakhir mungkin mewakili canggan rapuh akibat daripada kedudukan cetek jasad batuan sekurang-kurangnya di sepanjang segmen sesar tersebut.
  2. Syed Sheikh Almashoor
    The Bok Bak fault is a northwest-directed sinistral fault in northwest Peninsular Malaysia whose location was, by late 1980's, quite established. A postulated extension of 450 kilometres to the north-northwest has never been substantiated, but instead, speculated upon. The postulated extension in north Kedah, if there was any, had escaped detection of several mapping exercises, including modern approaches. The weak topography of the area and thick unconsolidated superficial deposits, apparently, are responsible for clouding the sensitivities of the modern methods. However, the conventional approach adopted in this study led to a successful discovery and definition of 82 kilometres of the Bok Bak fault in north Kedah and Perlis up to the Perlis (Malaysia)/Thailand boundary. It is in a dextral six-kilometre offset position with the established counterpart to its south. One significant fault­signature identified is a set of strike ridges which exhibit a left-lateral drag arrangement. Other fault-signatures include, fault planes and breccia, a sharp formational boundary, a spring locality, a lake, two linear rivers, a distorted river's course and a bent watershed line. One fault signature indicates that it is a wrench fault. With a zone of width 800 metres approximately and a total length of 215 kilometres, it is now established that the Bok Bak fault is a major fault in Peninsular Malaysia. Two pairs of correlatable rock units on opposite sides of the fault provide the first ever reliable displacement amount of about 10 km. It is discovered that the limestone hills (mogotes) running from north to central Perlis are not entirely of Chuping Formation. The last hill at the southernmost end (Bukit Ngulang) belongs to Setul Limestone Formation. The formational boundary between these hills, as implied by superficial fault-related features, is a fault contact; and is interpreted as a reliable signature of the Bok Bak fault. Based on similarities in hill-orientation, lithology and fossil contents, the Kodiang limestone mogotes in north Kedah are believed to be the continuation of the Chuping Limestone of central Perlis, but are now dispositioned by the Bok Bak fault.
    Sesar Bok Bak ialah sesar ke kiri mengarah ke baratlaut yang terletak di baratlaut Semenanjung Malaysia. Pada akhir tahun lapan puluhan lokasinya sudah termaklum. Unjurannya yang sejauh 450 km ke arah utara-baratdaya hanyalah satu spekulasi dan tidak pernah dibuktikan. Unjurannya yang diandaikan di utara Kedah tidak dapat dikesan walau pun beberapa pemetaan telah dibuat, termasuk yang menggunakan pendekatan moden. Topografi kawasan yang lemah dan permukaan bumi yang diselimuti oleh bahan tak terkonsolidasi yang tebal dipercayai telah melemahkan kepekaan kaedah moden. Walau bagaimanapun pendekatan konvensional yang diguna dalam kajian ini berjaya mengesan sepanjang 82 km sesar Bok Bak di utara Kedah dan Perlis hingga ke sempadan Perlis/Thailand. Sesar yang baru dikesan ini terganjak ke kanan sejauh 6 km daripada bahagian sesar yang sudah termaklum di selatan. Satu tanda sesar yang penting yang dikenal pasti adalah satu set permatang jurus yang mempamerkan susunan seret ke kiri. Tanda-tanda sesar lain termasuk satah-satah sesar dan breksia, sempadan formasi yang tajam, satu lokaliti mata air, satu tasik, sungai-sungai lurus, sebahagian sungai yang tererot, dan garis legeh yang bengkok. Satu tanda sesar menunjukkan sesar ini adalah jenis mendatar. Dengan zon berkelebaran 800 meter dan kepanjangan sejauh 215 km, terbuktilah bahawa sesar Bok Bak adalah satu sesar major di Semenanjung Malaysia. Dua pasang unit batuan yang boleh dikorelasi dan yang terletak di sisi timur dan barat sesar, pertama kali membenarkan nilai alihan ke atas sesar dianggarkan, iaitu sebanyak 10 km. Kajian juga mendapati bahawa bukit-bukit batu kapur (mogot) yang berbaris daripada utara ke tengah Perlis bukan kesemuanya batuan Formasi Chuping. Bukit yang terselatan sekali (Bukit Ngulang) ternyata komponen Formasi Setul. Fitur-fitur di permukaan membayangkan bahawa sempadan formasi antara bukit-bukit tersebut ialah sempadan sesar; dan sempadan ini dianggap sebagai tanda sesar Bok Bak yang menyakinkan. Berdasarkan kesamaan pada orientasi bukit-bukit, litologi dan kandungan fosil, mogot-mogot Batu Kapur Kodiang di utara Kedah dipercayai adalah sambungan kepada Batu Kapur Chuping di tengah Perlis, tetapi sekarang telah teralih oleh sesar Bok Bak.
  3. Abdul Razak Daud, Azleen Mohd. Zain, Azali Muhamad
    A single wall single image x-ray radiographic technique was adopted to investigate thickness variation of steel specimens caused by uniform corrosion. The ability of the 100 kV-160 kV x-rays to produce a meaningful film density for steel was also investigated. The thickness contour maps of corroded steel plates were found matching with the x-ray film density contour maps of the plates. The results confirm that x-ray radiography can be used to detect the thickness reduction of steel caused by uniform corrosion.
    Bagi mengesan perubahan ketebalan keluli akibat kakisan seragam maka radiografi sinar-x teknik imej tunggal dinding tunggal telah digunakan. Kemampuan sinar-x 100 kV-160 kV menghasilkan ketumpatan filem yang sesuai untuk keluli telah juga dikaji. Peta kontur ketebalan bagi spesimen kepingan keluli yang telah mengalami kakisan seragam didapati sepadan dengan peta kontur ketumpatan filem radiografi sinar-x bagi spesimen tersebut. Kajian ini menunjukkan radiografi sinar-x boleh digunakan bagi mengesan penipisan keluli akibat kakisan seragam.
  4. Sahibin Abdul Rahim
    A preliminary study on the concentration and distribution of heavy metals (Cd, Co, Cr, Cu, Ni, Pb and Zn) was carried out for the whole of Ranau District. Topsoil samples (0-15 cm depth) were collected randomly in accordance with the distribution of soil associations in the area. It was found that only three of the heavy metals (Ni, Cr, and Cu) were present above the threshold of toxicity level, whilst the others were below this level. These higher levels of heavy metal concentration were most likely associated with the mining activities in the headwater of the study area and also to the occurrence of serpentinite parent material. The area affected is confined only to the northern part of the study area.
    Kajian awal bagi menentukan taburan dan kepekatan logam-logam berat (Cd, Co, Cr, Cu, Ni, Pb dan Zn) telah dijalankan bagi seluruh daerah Ranau. Sample tanah atas (kedalaman 0-15 cm) telah dikutip secara rawak bergantung kepada taburan asosiasi tanah di kawasan tersebut. Didapati bahawa hanya tiga daripada logam berat ini (Ni, Cr dan Cu) melebihi had keracunan, sementara yang lain berada di bawah paras keracunan. Kepekatan logam berat yang tinggi di dalam sampel kajian' dapat dikaitkan dengan aktiviti pelombongan tembaga di kawasan punca air dan juga dengan batuan serpentinit yang menjadi bahan induk tanah. Kawasan yang terlibat terhad di bahagian utara kawasan kajian sahaja.
  5. Ahmad Nazlin Yusoff, Mustaffa Hj. Abdullah, Sahrin Hj. Ahmab, Ng L
    Sampels of Mnx-zMgzZn1-xFe2O4 ferrites, with x = 0.5, 0 < z < 0.5; x = 0.6, 0 < z 0.6 and x = 0.7, 0 < z < 0.7, were prepared by solid state reaction. For all samples, magnetization as a function of applied magnetic field was measured at room temperature (TR) and several temperatures above TR but below the Neel temperature (TN); while magnetic hysteresis was obtained at TR and 373 K using a vibrating sample magnetometer (VSM). Electrical resistivity at TR was measured by a two terminal method. The three series of Mn-Mg-Zn ferrite indicate a maximum ,agnetization at certain substitution of Mg. TN increased with the increase of Mg content while resistivity varied in the opposite manner. The variation of magnetization is interpreted as due to Mg started to replace the Mn at the tetrahedral sites (A) so that the resultant magnetic moment increased. However further substitution occurred at the octahedral sites (B), thus lowering the magnetic moment. A small coercivity indicates that the samples are soft ferrites with a small energy loss. A reduction in the electrical resistivity with Mg content probably due to an increase in the mobility of charge hopping between the Fe2+ and Fe3+ ions and also between Mn2+ and Mn3+ ions.
    Sampel ferit Mnx-zMgzZn1-xFe2O4 dengan x = 0.5, 0 < z < 0.5; x = 0.6, 0 < z 0.6 dan x = 0.7, 0 < z < 0.7, disediakan dengan tindak balas keadaan pepejal. Pengukuran pemagnetan sebagai fungsi medan magnet dilakukan pada suhu bilik (TR) dan suhu-suhu yang lebih tinggi tetapi di bawah suhu Neel bilik (TR) dan suhu-suhu yang lebih tinggi tetapi di bawah suhu Neel (TN) serta histerisis magnet pada suhu bilik dan 373 K diperolehi untuk semua sampel menggunakan magnetometer sampel bergetar (VSM). Kerintangan elektrik pada suhu bilik diperolehi dengan kaedah dua terminal. Ketiga-tiga siri ferit Mn-Mg-Zn itu masing-masing menunjukkan suatu pemagnetan maksimum pada suatu kadar penggantian Mn oleh Mg. TN meningkat dengan kandungan Mg tetapi kerintangan elektrik berubah sebaliknya. Perubahan pemagnetan seperti yang tersebut disebabkan Mg mula menggantikan Mn pada tapak tetrahedron (A) menyebabkan momen magnet paduan meningkat. Penambahan Mg seterusnya menyebabkan Mn pada tapak oktahedron pula diganti, sehingga momen magnet paduan mengurang. Koersiviti yang kecil menunjukkan sampel bersifat magnet lembut dengan kehilangan tenaga yang sangat kecil. Pengurangan kerintangan dengan penambahan Mg mungkin disebabkan oleh peningkatan kelincahan pembawa cas yang melompat di antara ion-ion Fe2+ dan Fe3+ dan juga di antara Mn2+ dan Mn3+.
  6. Amran B. Ab. Majid, Mohd Zahari Abdullah, Zaharuddin Ahmad
    The determination technique for U (238U, 235U, 234U) and Th (232Th, 230Th, 228Th) isotopes using alpha spectrometry was developed. The developed technique involved digestion, dissolution, coprecipitation, solvent extraction and electrodeposition methods. The NBS River Sediment and Rocky Flats Soil Standard Reference Materials were analysed to determine the accuracy of the technique. A good accuracy and high percentage recovery of the carrier (70 - 90%) indicated that the developed technique was suitable for U and Th isotopes determination. The technique was used to determine the U and Th concentration in monazite, xenotime and zircon samples. The results showed that the U and Th total concentrations were in the range of 21.03 to 171.25 Bq/g and 27.48 to 242.87 Bq/g respectively.
    Kaedah penguraian, pemelarutan, pemendakan bersama, ekstraksi pelarut dan pemendapan elektrik telah dikaji dan digunakan untuk mendapatkan suatu teknik yang terbaik dalam penentuan isotop uranium 234U, 235U & 238U) dan torium 228Th, 230Th & 232Th) menggunakan sistem spektrometri alfa. Kepekatan isotop U dan Th dalam bahan rujukan piawai River Sediment dan Rocky Flats Soil (NBS) telah dianalisis untuk menentukan kejituan teknik yang dibangunkan. Kajian ini mendapati kepekatan isotop yang diperolehi adalah menghampiri nilai teraku (sijil) dan peratus perolehan semula pembawa yang besar (70-90%). Ini menunjukkan teknik yang dibangunkan sesuai digunakan untuk penentuan isotop uranium dan torium. Seterusnya teknik yang dibangunkan telah digunakan untuk menentukan kandungan uranium dan torium dalam sampel monazit, xenotim dan zirkon tempatan. Kepekatan jumlah isotop uranium yang diperolehi didapati berada dalam julat 21.03 - 171.25 Bq/g manakala kepekatan jumlah isotop torium pula terletak antara 27.48 - 242.87 Bq/g.
  7. Abu Bakar Salleh, Razak C.N.A., Samad M.Y.A., Ampon K., Yunus W.M.Z.W., Basri M.
    Lipase from a newly isolated strain of Rhizopus rhizopodifonnis was partially purified and characterized. By acetone fractionation, the enzyme was purified to about 2.8 fold, with 62.5% recovery and with specific activity of 3.2 U/mg. By gel filtration through Sephadex G-100, the enzyme was further purified to 9.7 fold and had a specific activity of 11.1 U/mg. By polyacrylamide gel electrophoresis, five protein bands were observed after acetone fractionation, white two protein bands were observed after the preparation was passed through Sephadex G-100. It has a pH optimum at 6.0 and a temperature optimum at 45°C. The enzyme is most stable at pH 7.0 and temperature of 50°C. The enzyme has a preference for short chain triglycerides and can also hydrolyse some methyl esters. The lipase is specific for 1,3 positions.
    Lipase daripada satu stren Rhizopus rhizopodifonnis yang baru dipencilkan telah diseparatulen dan diciri. Melalui fraksi asiton, enzim telah ditulen lebih kurang 2.8 ganda, dengan pengutipan 62.5% dan aktiviti spesifik 3.2 U/mg. Dengan penurasan gel melalui Sephadex G-l00, enzim ditulenkan lagi hingga 9.7 ganda dengan aktiviti spesifik mencapai 11.1 U/mg. Dengan elektroforesis gel poliakritamida, 5 jalur protein didapati selepas fraksi asetone, sementara 2 jalur protein dilihati selepas penurasan gel Sephadex G-10. Enzim ini mempunyai pH optimum pada pH 6.0 dan suhu optimumnya ialah 45°C Enzim ini paling stabit pada pH 7.0 dan suhu 50°C Enzim mempunyai kepilihan pada trigliserida rantai pendek dan dapat menghidrolisiskan beberapa ester metit. Lipase ini spesifik pada posisi 1,3.
  8. Mohd Idris Jayes
    The discretization of the second-order linear self-adjoint ellliptic partial differential equation problem subject to periodic boundary conditions results in a system of linear equations of the form Mu = s, where M is a block cyclic tridiagonal square matric. In this paper, the relationship between the spectral radius and overrelaxation factor for the problem is derived.
    Pendiskretan masalah persamaan pembeza separa (PPS) eliptik swadampingan linear peringkat kedua menghasilkan satu sistem persamaan linear bentuk Mu = s, dengan M merupakan satu matriks segiempatsama tiga pepenjuru berkitar blok. Dalam kertas ini, hubungan di antara jejari spektrum dan faktor pengenduran berlebihan untuk masalah itu akan dirumuskan.
  9. Kamarulzaman bin Ibrahim
    An integral art of the Bayesian approach which is not present in the classical approach is the prior distribution. Different researchers may have different level of prior knowledge regarding the parameter of interest before seeing the data. Sometimes different prior distributions can result in different decisions, as such investigations have to be careful in making the choice of the prior distribution. In this paper, we compare results from the Bayesian analyses based on three possible choices of the prior distributions, which are uniform prior, lognormal prior and an improper prior, in the evaluation of the effectiveness of mini-roundabouts. Data from five before and after studies into the effect of mini-roundabouts when replacing priority junctions are used. The effects of the different prior distributions are distinguishable from the analysis of an anamolous 'desk-drawer' study. The uniform and improper prior pull the estimated treatment effect away from one more than the lognormal prior. The results based on lognormal prior depict a less worst scenario of the ineffectiveness of mini-roundabouts and this may correspond to the deficiency in engineering design at only a few sites. Consequently, it is more appropriate to use the lognormal prior in the analysis of mini-roundabouts as a road safety measure.
    Satu ciri yang penting dalam kaedah Bayesian yang tidak ada dalam kaedah klasik ialah taburan prior. Sebelum melihat data, mungkin setiap penyelidik mempunyai tahap pengetahuan prior yang berbeza berkenaan sesuatu parameter yang ingin dikaji. Kadang-kala taburan prior yang berlainan boleh menghasilkan keputusan yang berlainan. Oleh itu, pengkaji perlu berhati-hati dalam memilih taburan prior. Dalam kertas-kerja ini, kami bandingkan keputusan dari analisis Bayesian berdasarkan tiga pilihan taburan prior yang menasabah iaitu prior seragam, prior lognormal dan prior tak wajar untuk menilai keberkesanan bulatan mini. Data dari kajian-kajian sebelum dan selepas terhadap kesan mengantikan persimpangan dengan bulatan mini digunakan. Kesan taburan prior yang berlainan dapat dibezakan berasaskan keputusan analisis terhadap satu kajian 'laci-meja' yang ganjil. Prior seragam dan prior fak wajar felah menyebabkan anggaran nilai kesan rawatan melebihi satu lebih dari prior lognormal. Keputusan berasaskan prior lognormal ini menunjukkan senario yang kurang teruk tentang kurang berkesannya bulatan mini dan mungkin ini boleh dikaitkan dengan rekabentuk kejuruteraan yang tidak baik di beberapa tempat sahaja. Dengan itu, prior lognormal adalah lebih sesuai digunakan untuk menilai bulatan mini sebagai langkah keselamatan jalanraya.
  10. Nor Azah Mohamad Ali, Ibrahim Jantan, Sri Nurestri Abd. Malek, Zuriati Zakaria
    The chemical compositions of the leaf and bark oils of Xylopia caudata were examined by co-chromatography with authentic samples on a polar capillary column (PEG 20M) and a non polar capillary column (SE-30), GC/MS and further comparison with Kovats Retention Index. The essential oils were mainly made up of monoterpenoids. The major components in both oils were β-pinene, α-pinene, limonene and a-terpineol which collectively represented 90% and 69% of the leaf and bark oils respectively.
    Kandungan kimia minyak pati daun dan kulit kayu Xylopia caudata telah dikaji secara ko-kromatografi dengan sampel tulen di atas turus rerambut polar (PEG 20M) dan turus rerambut kurang polar (SE-30), KG/SJ dan perbandingan dengan Indeks Penahanan Kovats. Sebahagian besar minyak pati tersebut terdiri daripada sebatian monoterpenoid. Komponen utama yang terdapat dalam kedua-dua minyak pati tersebut adalah β-pinena, α-pinena, limonena dan a-terpineol yang mewakili 90% dan 69% daripada minyak pati daun dan kulit kayu masing-masing.
  11. Fasihuddin B.A., Laily B. Din, Zuriati Zakaria
    Three compounds were isolated and characterized from the roots of Goniothalamus woodii. Based on their spectroscopic data, the compounds were identified as goniothalamin, 5-acetoxygoniothalamin and goniotriol.
    Tiga sebatian telah dipisahkan dan dicamkan daripada akar Goniothalamus woodii. Berdasarkan dari data spektroskopi, sebatian telah dikenalpasti sebagai goniotalamin, 5-asetoksigoniotalamin dan goniotriol.
  12. Kamal Roslan Mohamed, Che Aziz Ali
    This study is based on a LANDSAT imagery of 1989, topographic maps and aerial photographs. Several stages of the delta's development have been identified based on the shape and the position of the former delta lobes and channels. The older delta complex shows a cuspate shape and a series of beach ridges in the south marks the position of the former shore lines. There is a clear distinction between the former delta complex and the present day complex. The former lobe shows a characteristic of a wave dominated delta system whilst the present complex is more of a fluvival-dominated type. The change in the delta type is believed to have been caused by the change of physiographic processes in the delta area as well as in the inland area. In the inland area, the Kelantan River has changed its course several times that were followed by delta-lobe switching. At the same time the river mouths migrate progressively towards the northwest. The Kemasin River mouth is the oldest river mouth detected from satellite's imagery and aerial photographs. The rivermouth then migrated to the north and forms the present day Kuala Pak Amat before it migrated further northwest to Pengkalan Datu. The migration of river mouth has led to the change of the deltaic processes. Earlier when the river mouth and the delta complex were located in the south they were subjected to direct wave action. At present most of the delta complex is subjected to the northwesterly longshore currents which have produced a series of sand spits. The presence of the sandspits which are sheltering the river mouth from wave action has led to more current and stream domination on the delta. Some older river channels which form dried­ up channels and dying streams can be clearly observed in the satellite imagery. There are also some remnant river channels which form elongated lakes and ox-bow lakes. Shapes and locations of the older river systems reveal that the main stream has changed its behavior from a meandering stream to a straight channel river system several times in its history. In the coastal areas, we have traced several older shorelines which had prograded progressively towards the sea. The progradation of shorelines is marked by a series of beach ridges which are parallel to the present day shoreline. The beach ridge can be traced up to 10 km inland from the present day beach line. Several topographic highs (Gunung Panchor and Bukit Marak) are believed to represent small hills or near shore islands during the beginning of the progradation.
    Kajian ini dilakukan berdasarkan imej LANDSAT TM tahun 1989, dan dibantu oleh peta topografi serta gambar udara. Beberapa peringkat pembentukan dan perkembangan Delta Kelantan ditafsirkan daripada bentuk dan kedudukan alur-alur dan permatang pantai kuno. Delta lebih tua berbentuk juring ("cuspate") dan beting-beting pasir di bahagian selatannya menandakan arah garis pantai terdahulu. Delta yang lebih tua ini lebih mencirikan delta kuasaan ombak, berbeza dengan delta yang sedang terbentuk sekarang. Perubahan daripada delta kuasaan ombak kepada delta kuasaan sungai terjadi akibat perubahan-perubahan di bahagian daratan dan pesisir pantai. Di bahagian daratan, imej LANDSAT TM menunjukkan Sungai Kelantan telah menukar arah aliran beberapa kali dan ini mengakibatkan perubahan kedudukan muara. Imej yang diperolehi juga menunjukkan terdapat banyak alur-alur sungai tua yang luas tetapi mempunyai aliran yang kecil, ataupun alur-alur yang kering. Selain itu terdapat juga beberapa tasik memanjang dan tasik ladam, hasil tinggalan sungai lampau. Daripada bentuk dan kedudukan alur-alur sungai tua ini, dapat ditafsirkan sungai utama telah berubah berbentuk dari berliku menjadi lurus beberapa kali. Di bahagian pantai pula telah dikesan garis pantai telah berkembang secara progressif ke arah laut (progradasi). Perkembangan garis pantai ditandai oleh permatang pantai yang berkedudukan hampir selari dengan garis pantai sekarang. Permatang pasir ini boleh dikesan hingga 10 km daripada garis pantai sekarang. Pada peringkat awal pembentukan Delta Kelantan, bukit Gunung Panchor (pekan Gunung) dan Bukit Marak merupakan sebuah pulau atau bukit di pesisir pantai sementara kedudukan bandar Kota Bharu masih terletak di laut. Pada masa yang sama muara sungai berhijrah secara berperingkat-peringkat ke arah baratlaut. Muara terawal yang dapat dikesan merupakan muara Sungai Kemasin dan kemudian menghijrah ke muara Pengkalan Datu. Sebelum berubah kepada kedudukan sekarang, muara Sungai Kelantan telah berhijrah daripada Pengkalan Datu ke Kuala Pak Amat. Perubahan kedudukan muara menyebabkan tindakan proses fizikal (rambatan ombak, angin dan arus pantai) berbeza daripada sebelumnya. Pada masa ini sebahagian besar daripada bahagian luar kompleks delta dipengaruhi oleh aliran pesisir pantai yang menghasilkan pembentukan anak tanjung pasir (sand spit) di bahagian pinggir delta. Kehadiran anak tanjung pasir secara langsung melindung kompleks delta daripada tindakan ombak dan menyebabkan pengaruh luahan sungai dan pasang surut lebih dominan di bahagian dalam kompleks.
  13. Kamal Roslan Mohamed
    The Semantan Formation which is Middle to Upper Triassic age, comprises a rapidly alternating sequence of carbonaceous shale, siltstone and rhyolite tuff with a few lenses of chert, conglomerate and recrystallised limestone. The shale and tuff make up the bulk of the sequence. Jaafar Ahmad (1976) was introduced the formation name of the rock sequence in Karak-Temerloh area, but the similar sequence (in term of lithology, paleontology and structural pattern) found in the other areas were given different names. After an extensive study, the following formations or part of them, may be include in the Semantan Formation; Raub Series (Scrivenor 1911); Calcareous Formation (Richardson 1939); Calcareous Series (Richardson 1947); Younger arenaceous Series (Alexander 1956); Raub Group (Alexander 1959); Jengka Pass Formation (Ichikawa et al. 1966); Kerdau Formation (Burton 1973a); part of Jelai Formation (Burton 1973a); Gemas Formation (Lum 1977); Jurong Formation (Burton 1973a); Pahang Volcanic Series (Hutchison 1973c).
    Formasi Semantan merupakan jujukan batuan sedimen yang berusia Trias Tengah - Akhir di Jalur Tengah Semenanjung Malaysia. Jujukan ini terdiri daripada selang lapis batuan syal berkarbon, batu lodak, dan batu pasir yang kebanyakannya bertuf, serta terdapat kekanta konglomerat, batu kapur dan rijang dalam selang lapis ini. Syal adalah unit yang paling dominan dalam formasi ini. Jaafar Ahmad (1976) menamakan jujukan ini untuk kawasan Karak - Temerloh, tetapi jujukan yang serupa (dari segi litologi, paleontologi dan gaya struktur) juga ditemui di kawasan lain, tetapi dipanggil dengan nama lain. Dari hasil kajian menyeluruh yang telah dijalankan, didapati nama-nama unit batuan berikut atau sebahagian daripadanya mungkin merupakan penamaan yang serupa untuk Formasi Semantan, iaitu Siri Raub (Scrivenor 1911), Formasi Berkapur (Richardson 1939), Siri Berkapur (Richardson 1947), Siri Arenit Muda (Alexander 1958), sebahagian Kumpulan Raub (Alexander 1959), Formasi Jengka Pass (Ichikawa et al. 1966), Formasi Kerdau (Burton 1973a), sebahagian Formasi Jelai (Burton 1973a), Formasi Gemas (Lum 1977), Formasi Jurong (Burton 1973a) dan Siri Volkano Pahang (Hutchison 1973).
  14. Basir Jasin
    Chemical compositions, and radiolarian content of several Late Paleozoic and Mesozoic chert samples have been studied. The occurrence of radiolaria in the chert permits dating of the rock more accurate. The age of the Kubang Pasu chert is Early Carboniferous. The age of the Kodiang chert is Carnian­Norian, Late Triassic. The age of the Semanggol chert ranges from Late Permian to Middle Triassic. The cherts from Ulu Kelantan and Jengka area I are dated as Early Permian and late Permian respectively. Three lithologic I associations are recognised; 1) chert-limestone association represents a subsidence association which is found at the Kodiang Formation, 2) chertclastic association represents continental margin chert association which is very common in Peninsular Malaysia. It is found in the Semanggol Formation, Kubang Pasu Formation, and the chert from Ulu Kelantan, and 3) chertpyroclastic association which represents island-arc association is found in the chert at the Jengka area, Pahang.
    Beberapa contoh rijang berusia Paleozoic Akhir dan Mesozoik telah dikaji kandungan kimia, dan radiolaria. Kewujudan radiolaria dalam bantuan rijang telah membolehkan penentuan usia yang lebih jitu terhadap lapisan rijang di beberapa formasi batuan di Semenanjung Malaysia. Rijang Formasi Kubang Pasu berusia Karbon Awal. Rijang Formasi Kodiang berusia Karnian Norian, Trias Akhir. Rijang Formasi Semanggol berusia Perm Akhir hingga Trias Tengah. Rijang di kawasan Ulu Kelantan berusia Perm Bawah. Rijang di kawasan Jengka, Pahang berusia Perm Akhir. Tiga sekutuan batuan rijang telah dikenalpasti; 1) sekutuan rijang-batu kapur atau dikenali sebagai sekutuan ambelesan yang didapati di Formasi Kodiang, 2) sekutuan rijang­batuan klastik atau dikenali sebagai sekutuan rijang pinggir benua, sekutuan ini banyak ditemui di Semenanjung Malaysia terutama dalam Formasi Semanggol, Formasi Kubang Pasu dan rijang di Ulu Kelantan dan 3) sekutuan rijang-piroklastik atau dikenali sebagai sekutuan arka-kepulauan didapati pada batuan rijang di kawasan Jengka, Pahang.
  15. Tan BK
    Some 20 basalt soil samples from the Kuantan area were analysed for their physico-chemical properties. The physical properties of the soils analysed are: relative density, water content, the Atterberg Limits, grain size distribution, and compaction properties. The chemical properties analysed involved the pore fluids chemistry, whereby the pore fluids of the soils were first extracted using the "Saturation Extract" method and then subsequently analysed for pH, conductivity, cations (Na+, K+, Ca2+, Mg2+)concentrations, and anions (SO42-, Cl-, CO32-, HCO3-) concentrations. The results show the following characteristics for the basalt soils: relative density is high with most values> 2.7; water content is generally high with Wo > 30% indicating high adsorption of water; liquid limits can attain high values in excess of 50%; grain size comprises the whole range from G (grave) to C (clay), but is predominantly fine-grained (M/C); the fines fractions of the soils are classified under ML-MH soils, ie silts with low-high plasticity. Surprisingly, the compacted maximum dry densities show rather low values ranging from 1.22-160 g/cm3 in spite of the fact that basalt soils generally make good embankment fill materials. The low gdmak values could be atrributed to the rather high optimum moisture contents of the soils (Wopt = 29.0-47.5%). Results for the pore fluids chemistry indicate the following: pH is on the acidic side « 7); conductivity is low, reflecting the low cations contents of the pore fluids; cations Na+, K+, Mg2+, Ca2+ are generally low in concentrations, with K+, Ca2+ & Mg2+ all having values of < 5ppm. Interestingly enough, there appears to be a distinct predominance of Na+ concentrations. As such, the ratios of monovalent cations (Na+ + K+) versus divalent cations (Ca2+ + Mg2+) show high values ranging from 3-17, with a few values being in excess of 100, thus indicating the high dispersivity of the basalt soils. Anions Cl-, CO32- and HCO3- were not detected, while SO42- shows considerable values of 35-122 NTU. Although in the field the soil profile shows 3 distinct layer or horizonations having colours ranging from (top to bottom) dark brown, red, to purple, it would appear from the test results obtained that the physico-chemical properties of the soil samples taken from these 3 horizons do not show any siginificant differences or variations from one another, contrary to expectations. Moreover, some of the physico­chemical properties of the basalt soils taken from the same layer/horizon also appear to plot in 2 distinct clusters - the reasons for this are not entirely clear.
    Sebanyak 20 sampel tanah basalt dari kawasan Kuantan telah diuji sifat fiziko-kimia tanah tersebut. Sifat fizik tanah yang diuji ialah: ketumpatan relatif, kandungan air. Had Atterberg, taburan saiz butiran, dan sifat pemadatan. Sifat kimia yang diuji pula melibatkan kimia air liang. Air liang tanah diekstrak dahulu dengan kaedah "Ekstrak Tepuan" dan kemudiannya diuji pH, kekonduksian, konsentrasi kation (Na+, K+, Ca2+, Mg2+) dan anion (SO42-, Cl-, CO32-, HCO3-). Hasil kajian menunjukkan ciri-ciri tanah basalt sepertimana yang berikut: ketumpatan relatif tinggi, dengan kebanyakan nilai > 2.7; kandungan air secara umumnya tinggi dengan Wo > 30%, ini menunjukkan penjerapan air yang tinggi; had cecair boleh mencapai nilai yang tinggi yang melebihi 50%; saiz butiran tertabur luas an tara saiz kelikir (G) hingga saiz lempung (C), namun demikian saiz dominan adalah halus (M/C); fraksi tanah halus dikelaskan sebagai tanah ML-MH, iaitu lodak dengan keplastikan rendah-tinggi. Yang agak mengejutkan ialah nilai ketumpatan kering maksimum tanah terpadat yang agak rendah, bersela antara 1.22-1.60g/cm3, walaupun tanah basalt diketahui umum sebagai bahan tambakan yang baik. Nilai gdmak yang rendah itu boleh disebabkan kandungan air optimum yang tinggi (Wopt = 29.0-47.5%). Keputusan untuk kimia air liang menunjukkan perkara yang berikut: PH terletak pada sebelah asid (< 7); kekonduksian rendah, membayangkan kandungan kation yang rendah; kepekatan kation Na+, K+, Mg2+, Ca2+, secara umumnya adalah rendah, dengan K+, Ca2+ dan Mg2+ mempamerkan nilai < 5bpj. Seperkara yang agak menarik ialah kedominanan kepekatan Na+ yang jelas. Dengan itu, nisbah kation monovalensi (Na+ + K+) lawan dwivalensi (Ca2+ + Mg2+) menunjukkan nilai yang tinggi yang berjulat antara 3-17, dengan beberapa nilai yang melebihi 100, maka ia menunjukkan potensi penyerakan tanah basalt yang tinggi. Anion Cl-, CO32- dan HCO3- tidak dikesan, manakala SO42- memaparkan nilai yang agak tinggi, iaitu 35-122 NTU. Walaupun di lapangan prolil tanah basalt memperlihatkan 3 lapisan atau horizon yang jelas, dengan warna yang berubah (atas ke bawah) daripada coklat tua, merah hingga ungu, hasil kajian sifat fiziko-kimia sampel tanah yang telah diambil dari 3 horizon itu tidak menunjukkan perbezaan atau variasi yang penting, iaitu lain daripada jangkaan. Tambahan pula, beberapa sifat fiziko­kimia tanah basalt yang telah diambil dari lapisan yang sama terplot pada dua kelompok yang jelas - penerangan untuk perkara ini tidak begitu jelas.
  16. Zaleha M.I., Osman A., Iskandar Z.A., Zainuddin B., Mohd. Ali M., Khalid B.A.K.
    Sains Malaysiana, 1996;25(2):51-58.
    Goitre prevalence and mental performance were determined amongst the Aborigines in Sinderut, a remote rural area in Pahang. A total of 196 subjects aged 4 to 60 years old were selected for study. Goitre status was determined by an experienced endocrinologist using classification suggested by World Health Organization; while mental performance was measured using Raven's test (Oxford Psychologists Press). Blood specimen was also taken for thyroxine (T4) and thyroid stimulating hormone (TSH) measurement. It was found that goitre prevalence was 26.5% (52/196); with visible goitre prevalence of 42.3% (22152). The overall mean of goitre volume was 21.4 ± 19.1 ml (range: 3.0 - 90.8 ml), while the prevalence of mental performance for the percentile value of more than 5.0 was 26.5% (range: 5.0 - 50.0). Mean thyroxine levels was 75.4 ± 19.3 nmol/L (range: 19.9 - 138.1 nmol/ L) while mean levels of thyroid stimulating hormone was 4.9 ± 3.2 mU/L (range: 0.4 - 18.9 mU/L). There was no significant correlation between hormone levels and mental performance score (Pearson Correlation; T4 : r=-0.002, p=0.9736; TSH : r=0.10, p=0.1843). goitre volume and mental performance score (Pearson Correlation; r=-0.02, p=0.8395). Goitre prevalence of more than 20% in this area indicates a moderate endemia, while mental performance showed a low thinking level in the Aborigines particularly those who lived in remote areas.
  17. Kaur S, Kulikowski J
    This study was conducted to see if slow test presentations of 1 Hz was detected by the chromatic system and higher rates of flicker of 25 Hz, 33 Hz and 40 Hz were detected by the pure flicker system at lower and higher background luminances. Spectral sensitivity measurements were carried out using a 1.2 degree test spot presented at a rate of 1 Hz, 25 Hz, 33 Hz and 40 Hz on a white background. The background luminance used were 100 td, 250 td, 500 td, 750 td, 1000 td, 2500 td and 4000 td. The study showed that the detection of a 1 Hz test is possible by 2 mechanisms, the chromatic system at high background luminance and the achromatic and chromatic systems at low background luminance. In the case 25 Hz, it is not entirely detected by the 'pure flicker system' and the transient achromatic system might contribute in its detection. Flicker rates of 33 Hz and higher are detected by the pure flicker system.
    Kajian ini dilakukan untuk melihat sama ada presentasi ujian secara perlahan iaitu 1 Hz dikesan oleh sistem kromatik dan ketipan pada kadar yang tinggi, iaitu 25 Hz, 33 Hz dan 40 Hz dikesan oleh sistem ketipan yang tutin pada luminans latar belakang rendah dan tinggi. Pengukuran sensitiviti spektral telah dijalankan dengan menggunakan satu cahaya ujian bulat berukuran 1.2 darjah yang dipersembahkan pada kadar 1 Hz, 25 Hz, 33 Hz dan 40 Hz pada latar belakang putih. Luminans latar belakang yang telah digunakan adalah 100 td, 250 td, 500 td, 750 td, 1000 td dan 4000 td. Kajian ini menunjukkan yang pengesanan ujian 1 Hz adalah melalui 2 mekanisma, mungkin sistem kromatik pada luminans latar belakang yang tinggi dan sistem akromatik dan kromatik pada luminans latar belakang yang rendah. Bagi 25 Hz pula, ia tidak secara keseluruhannya dikesan oleh sistem kelipan yang tutin dan mungkin sistem akromatik transien yang terlibat dalam pengesanannya. kadar ketipan 33 Hz dan lebih darinya adalah dikesan oleh sistem ketipan yang tulin.
  18. Ong BL
    Sains Malaysiana, 1996;25(3):13-18.
    A retrospective study of the incidence of Giant Papillary Conjunctivitis (GPC) seen in the Optometry clinic in Universiti Kebangsaan Malaysia from 1989 to 1994 was carried out. In the period of the 6 years, 37 contact wearers were diagnosed to have GPC. Of the 37 patients, 21 were Malays (57%), 12 were Chinese (32%) and the remaining 4 patients were Indians (11%). 18 or 48% of those with GPC were soft lens wearers, 46% of the wearers (17 patients) were rigid gas permeable lens wearers and 1 of the patients seen was a hard (PMMA) wearer (3%) and the other one was a disposable lens wearer (3%). Thirty patients were female (81%) and 7 (19%) were male. The age range of those with GPC were between 9 to 60 years old.
    Study site: Optometry clinic, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
  19. Ahamad Shabir Saari
    By using sequences of linear maps on C*-algebras, we consider sets known as Korovkin sets, i.e. sets of the form
    {a ε Asd/фn(a) → фo(a), фn(a2)→ фo (a2) = фo (a)2} In this paper we prove that if {фn} is a sequence of weak Kadison maps and '→' means norm, strong or weak convergence, then the Korovkin sets are JC-algebras. Furthermore if we assume that {фn} is a sequence of Schwarz maps or anti-Schwarz maps respectively, then the Korovkin sets become reversible JC-algebras.
    Dengan menggunakan beberapa jenis jujukan pemetaan linear {фn} atas aljabar-C*, kita pertimbangkan set yang dikenali sebagai set Korovkin, i.i. set berbentuk {a ε Asd/фn(a) → фo(a), фn(a2)→ фo (a2) = фo (a)2} Dalam kertas ini ditunjukkan bahawa jika {фn} adalah jujukan pemetaan Kadison lemah dan penumpuan '→' menandakan penumpuan norma, kuat atau lemah, maka set Korovkin adalah aljabar-JC. Dengan andaian yang lebih kuat, i.i. {фn} masing-masing jujukan Schwarz atau anti-Schwarz, ditunjukkan bahawa set Korovkin merupakan aljabar-JC berbalik.
  20. Abdul Hamid Othman, Ibrahim Baba, Yang Farina Abdul Aziz, Norman Awang
    Several triphenylphosphinosilver (I) complexes, viz. bis [acetatotriphenylphosphineargentum (I)], I, lactatotris (triphenylphosphine) argentum (I), II, N, N-diethanoldithiocarbamatobis (triphenylphosphine) silver (I), III, and N­ethanol, N-methyldithiocarbamatobis (triphenylphosphine) silver (I), IV, have been prepared. Apart from characterization by spectroscopic methods, the structures of I-III, have been characterised by single-crystal x-ray diffraction methods. I crystallized as a dimer with a 4-coordinate geometry around the silver atom, while the lactate complex is a monomer with a five-coordinate silver atom. In the four-coordinate complex III, the Ag - S bond distances are 2.6822 (13) and 2.5991 (12) Å indicating different modes of bonding to the dithiocarbamate ligands.
    Beberapa kompleks trifenilfosfinoargentum telah disintesis, iaitu bis [asetatotrifenilfosfinargentum (I)], I, laktatotris (trifenilfosfin) argentum (I), II dietanolditiokarbamatobis (trifenilfosfin) argentum (I), III dan metiletanolditiokarbamatobis (trifenilfosfin) argentum (I), IV. Selain daripada pencirian dengan kaedqh spektroskopi, struktur kompleks I-III telah ditentukan dengan kaedah pembelauan sinar-X hablur tunggal. Kompleks asetat terhablur sebagai dimer dengan argentum menunjukkan geomertri 4-koordinat, sementara kompleks laktat adalah monomer dengan argentum berkoordinatan lima. Dalam kompleks dietanolditiokarbamat argentum berkoordinatan empat dengan panjang ikatan Ag - S, 2.6822 (13) dan 2.5991 (12) Ã… menunjukkan dua mod pengikatan yang berbeza dengan ditiokarbamat.
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links