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Abstrak :
Ruang Terbuka Hijau (RTH) aktual tahun 1999 yang luasnya mencapai 41% dari Iuas wilayah Jakarta, mempunyai kandungan biomassa hijau 330.556 ton. Kondisi ini hanya mampu mendukung sekitar dua per tiga penduduknya. Berkurangnya ruang terbuka hijau maka daya dukung untuk memenuhi kebutuhan udara bersih bagi penduduk menurun pula. Hal ini akan memberikan dampak negatif yakni penurunan kualitas lingkungan hidup di wilayah tersebut. Hal ini diperkuat dengan penelitian yang menginformasikan terjadinya penurunan Iuas RTH 13 DAS yang melalui Jakarta dari tahun 1970 - 2000 di seluruh wilayahnya, dari Iuas RTH tahun 1970 yakni 52.179.33 ha berubah menjadi 15.117.77 ha pada tahun 2000. Dalam paparan di BPLHD DKI Jakarta dinyatakan bahwa meningkatnya luas bangunan beton, plesteran da aspal ± 18.798,5 ha atau + 28,7% Iuas daratan Jakarta, hingga menyebabkan tingginya laju limpasan air hujan dan laju tingkat erosi 152,7 ton/ha/tahun pada wilayah kikisan, serta meluasnya wilayah endapan sebagai akibat hasil sedimentasi yang berpengaruh, bahkan memberikan dampak terhadap semakin meluasnya wilayah genangan musiman ± 5.640 ha atau 8,6% dari luas daratan Jakarta. Dengan meningkatnya bangunan berdinding kaca f 4.061 ha atau 6,25 % dari luas daratan Jakarta, menyebabkan meningkatnya kutub-kutub panas kota, yaitu dari suhu udara rata-rata dari 28°C menjadi 29,1°C. Berdasarkan latar belakang tersebut di atas, tampak bahwa telah terjadi kerusakan lingkungan. Secara mendasar kondisi lingkungan hidup terus menurun di kawasan perkotaan, dikarenakan terus menurunnya luas daerah terbuka, sehingga menurunkan daya dukung lingkungan (fungsi ekologi vegetasi) Kota Jakarta. Berkaitan dengan permasalahan di atas, yaitu perubahan penggunaan tanah menyebabkan menurunnya daya dukung lingkungan, tujuan penelitian ini adalah Pertama, mengetahui hubungan antara jenis penggunaan tanah dan perubahannya dengan daya dukung lingkungan di wilayah Kota Jakarta. Kedua, mengetahui kapasitas daya dukung lingkungan di wilayah Kota Jakarta. Ketiga, mengetahui kaitan antara manusia dengan perubahan penggunaan tanah dan daya dukung di wilayah Kota Jakarta. Pendekatan penelitian dilakukan secara kuantitatif dengan menggunakan metode expostfactoyang dibahas secara deskriptif analitis. Data yang digunakan berupa data table dan peta yang diambil dari instansi terkait. Daya dukung yang diteliti hanya fungsi ekologis vegetasi yakni memperbaiki suhu (ameliorasi iklim) dan penyerap air hujan (hidrologis). Kesimpulan yang dapat ditarik dari penelitian ini adalah: Pertama, suhu dan air larian dipengaruhi oleh jenis penggunaan tanah, yaitu: (a) perbedaan jenis penggunaan tanah menyebabkan perbedaan suhu yang terjadi. Lokasi sekitar Kantor Walikota Jakarta Barat memiliki suhu paling rendah dari lokasi lainnya. Wilayah Kota Jakarta Timur tahun 2003 memiliki suhu paling rendah dari Jakarta Pusat dan Kota Jakarta Selatan. (b) perbedaan jenis penggunaan tanah menyebabkan perbedaan air larian. Lokasi Kantor Walikota Jakarta Barat persentase air larian lebih sedikit dari lokasi lainnya. Wilayah Kota Jakarta Timur air larian lebih sedikit dari Wilayah Kota Jakarta Pusat dan Selatan. Hal ini menunjukkan bahwa luasan vegetasi punya peran dalam perbedaan suhu dan air larian sebagal daya dukung lingkungan hidup dalam hal fungsi ekologis, maka terlihat kaitan antara penggunaan tanah dengan daya dukung lingkungan hidup. Kedua, perubahan penggunanan tanah menyebabkan penurunan Iuasan vegetasi yang berakibat dengan berubahnya suhu dan kemampuan untuk meresapkan air, sehingga air larian menjadi meningkat. Tahun 1940 penggunaan tanah terbangun dan terbuka proporsinya adalah 20 : 80, sedangkan tahun 2003 penggunaan tanah terbangun dan terbuka proporsinya adalah 74 : 26, hal ini menyebabkan: (a) Jakarta pada tahun 1940 suhu masih dibawah angka 27°C (suhu nyaman) yakni 26,48°C, sedangkan pada tahun 2003 suhu sudah melebihi suhu nyaman yakni suhu mencapai angka 31,48°C. (b) Persentase air larian pada tahun 1940 adalah 22% dari volume hujan setahun, sedangkan tahun 2003 telah mencapal 60.38% dari volume ar hujan setahun. Hal ini menunjukkan bahwa perubahan penggunaan tanah menyebabkan penurunan luasan vegetasi, yang mengakibatkan perubahan daya dukung lingkungan hidup dalam hai fungsi ekologis, sehingga suhu dan air larian meningkat. Hal ini menunjukkan adanya kaitan antara perubahan penggunaan dan penurunan daya dukung Iingkurigan hidup di wilayah Jakarta. Ketiga, kapasitas daya dukung Jakarta tahun 1940 masih melebihi 100% sedangkan tahun 2003 menurun 86,76% untuk memperbaiki suhu (ikiim), sedangkan kapasitas daya dukung menyerap air hujan tahun 1940 masih 100% sedangkan tahun 2003 menurun menjadi 66,25% setahun, untuk proporsi penggunaan tanah terbangun dengan terbuka 76 : 24 pada tahun 2003. Berdasarkan hal ini maka pada tahun 2010 sesuai dengan Rencana Umum Tata Ruang Jakarta proporsi penggunaan tanah terbangun dengan terbuka 87 : 13 dapat diprediksikan suhu menjadi lebih panas dan air larian meningkat yang menjadi potensi banjir akan semakin meluas. Keempat, manusia tidak hanya jumiahnya yang mempengaruhi perubahan penggunaan tanah, melainkan aktivitas yang membutuhkan ruang. Tahun 1940 jenis pekerjaan adalah lebih banyak petani sehingga luasan lahan pertanian (sawah, ladang, kebun, tambak) masih luas. Tahun 2003 luasan permukiman lebih luas dari lahan pertanian. Hal ini menggambarkan profesi petani tergantikan dengan profesi non petani (pegawai, jasa, di!). (b) perubahan penggunaan tanah memberikan dampak pada penurunan daya dukung lingkungan yakni kenaikan suhu dan menyebabkan banjir yang berkibat timbuinya biaya perbaikan dan biaya pengobatan. Berdasarkan hasii peneiitian ini maka beberapa saran yang diajukan adalah sebagai berikut: Pertama, pemerintah hares melakukan pemantauan perubahan penggunaan tanah dan mempertahankan luasan vegetasi yang masih ada serta meningkatkan kualitasnya, agar tercipta strata tajuk yang Iengkap dan rapat agar fungsi ekologinya meningkat. Kedua, pemerintah dan masyarakat perlu meningkatkan kuantitas luasan vegetasi dengan cara membuat tanaman rambat dengan jaring di dinding (rumah, perkantoran atau pertokoan) atau membuat pot tanaman yang diletakkan vertikal di sepanjang dinding, yang disesuaikan dengan jenis tanaman dan estetika. Ketiga, memperbesar kuantitas air hujan yang terserap ke dalam tanah dengan memberlakukan secara ketat pelaksanaan sumur resapan di rumah perkantoran dan pertokoan, sehingga dapat menjadi asupan air tanah agar tidak terjadi dampak banjir di musim hujan dan kekurangan air di musim kemarau. Keempat, membangun sumur resapan dan saluran air di sepanjang jalan, baik jalan utama maupun jalan lokal, sebagai tempat limpasan air saat hujan, serta membuat saluran air tersebut juga berfungsi sebagai sarana resapan air dengan tidak membuat bagian dasamya kedap air.

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In the year of 1999, existing green area in Jakarta reached 41% of the total area, and it contains 330.556 tons of green biomass. This condition only could support two-third of its population. With the lack of green area, it makes the carrying capacity to fulfill the need of clean air for the population also decreasing. This situation gives a negative impact on the environment, and it was strengthened by Tambunan's research in 2005 which described on decreasing green area of 13 watersheds which passed trough Jakarta from 52.179,33 hectares in the year 1970 becoming 15.117,77 hectares in 2000. The increasing area of concrete buildings, cements, and asphalt surface in Jakarta ± 18.798,5 Ha or ± 28,7% of Jakarta causes the high surface run off and erosion in the area or 152,7 tons/ha/year, also creating a vast sedimentation area and effecting on the wide spreading of inundation area ± 5.640 hectare or 8,6% of Jakarta. This meant the increasing number of glass buildings ± 4.061 hectare or 6,25 % of Jakarta causes the increasing of the city temperature from 28°C to 29,1°C. Based on the background, it looks like there has been an environmental damage. Basically, the conditions of the environment in the cities are always descending because of the decreasing of the open area and also causing the deteriorating of environment carrying capacity (vegetation ecological function). Related to the problems that certain land use changes cause the descending of environment carrying capacity, the purposes of this research are: (1) To observe the relationship between land use with its changes and the environment carrying capacity in Jakarta City. (2) To observe the environment carrying capacity in Jakarta City. (3) To observe the relationship between human being and land use change and the carrying capacity in Jakarta City.Quantitative approach of this research is carried out by using the ex post facto method and analyzed by descriptive analytic method. The data that being used are tabular data and spatial (maps) data taken from related institutions. Several conclusions of this research can be withdrawn: First, run off and temperature influenced by type of land use, that is: (a) the type of land use affecting the temperature condition of the area. Location around West Jakarta City Hall office has the lowest temperature than other location. Temperatures in East Jakarta are lower than Central and South Jakarta. (b) Difference of type East Jakarta are lower than Central and South Jakarta. (b) Difference of type land use cause difference run off. Location around West Jakarta City Hall has the lowest run off than other location. Run off in East Jakarta are lower than Central and South Jakarta. This matter indicate that vegetation area have a role in run off differentiation and temperature as environmental carrying capacity in the case of ecological function, it shown that there is a relationship between land use and environmental carrying capacity. Second, land use changes cause the decreasing of vegetation area and gives impact on the increasing temperature and run off. In 1940 the proportion of build up and open area was 20 : 80, while in 2003 the proportion of build up and open area are 74 : 26, this matter cause: (a) Jakarta in 1940 temperature still below 27°C (balmy temperature) which is 26,48°C, while in 2003 temperature have exceeded balmy temperature namely tired temperature of 31,48°C. (b) Percentage run off in 1940 is 22% of one year rain volume, while in 2003 has reached 60.38% of one year rain volume. This indicate that the changing of land use cause the changing of vegetation area, and environmental carrying capacity, resulting on the increasing of temperature and run off. It shown that there is a relationship between the changing of land use and carrying capacity. Third, In 1940 carrying capacity still over 100% and in 2003 carrying capacity become 86,76% to get the ideal temperature and carrying capacity for water absorption still 100% and in 2003 carrying capacity for water absorption become 66,25% to get the ideal water absorption, those condition for proportion of build up and open area of 74 : 26. Base on those conditions in 2010 the proportion of build up and open area are 87 : 13, this mean the temperature and run off will be higher. Fourth, the human being also can affect the environments by their occupation and quantities: (a) the occupation on 1940 most of the farmer's causes the agriculture area (paddy field, plantation, and fishpond) still vast. In 2003 the settlement area more than the agriculture area. (b) land use changes cause the decreasing carrying capacity which is the high temperatures and flood, causing the government and people's spent more money for healthy and maintenance cost. Several recommendations are: First, the government has to conduct monitoring of usage of land use and maintain the green area and also upgrade the quality, to create a complete and closed vegetations canopy, so it will increase the ecological function. Second, Government and society should improve amount of green area in their homes and office. Third, to create a large amount of water that can be absorb by soil, by creating an absorption well in house and office in order to mitigate the effect of flood and a water supply in the dry season. Fourth, to create abso;ption well and aqueduct alongside the main road and also local road; as place for run off, and also make the aqueduct also function as a medium for absorption without making its base waterproof.

Abstrak :
Sejalan dengan penambahan jumlah populasi di Jakarta kebutuhan akan perumahan ikut bertambah Salah satu tipe perumahan yang diminati khususnya oleh masyarakat berpenghasilan tinggi adalah Townhouse Saat ini Townhouse berkembang cepat di Selatan Jakarta yang merupakan daerah resapan air Ini bisa berdampak pada peningkatan potensi banjir di area lain Jakarta Rencana tata ruang yang telah dibuat oleh pemerintah juga tidak dapat mendukung terciptanya keseimbangan alam yang dibutuhkan oleh masyarakat luas Penelitian ini di tujukan untuk menemukan keberadaan Townhouse di Jakarta dan kesesuaianya dengan kondisi Jakarta selatan sebagai daerah resapan air serta pemahaman pihak pengembang dan penghuni Townhouse mengenai dampak pembangunanya terhadap lingkungan Jakarta Analisa yang di buat menggunakan metode kualitatif yang terdiri dari observasi wawancara dan studi literatur Hasilnya menunjukan bahwa dalam jangka pendek pengembangan Townhouse sesuia dengan kebutuhan masyarakat Namun jangka panjang dapat berdampak negatif bagi kualitas kehidupan masyarakat Jakarta. ......In line with the increase of population number in Jakarta , the need for housing increases as well. One of the housing types which preferred particularly by the community of high-income group is the townhouse. Nowadays townhouses are developing rapidly in South Jakarta wich is a water absorption area. This could have an impact on increasing the potential of flooding in other areas in Jakarta. Spatial Plan area made by the Government also does not support the creation of natural balance needs to be maintained for the sake of life of wider community. This research is aimed to find out the existence of Townhouses in South Jakarta and their appropriateness with the regional condition of South Jakarta as water absorption and the developers? and townhouses? residents understanding concerning the impact of townhouse constructions to Jakarta?s city environment.The analysis undertaken in this study using qualitative methods which consists of observation, interview and documentary study. The results showed in the short term the townhouse development is still appropriate to meet the needs of the home society.But for the long term can have negative impact for the quality of public life in Jakarta

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Istilah ?Ramah Lingkungan? untuk kulit dapat diartikan sebagai kulit tersamak yang bebas krom. Hampir 80% penyamakan saat ini menggunakan krom, karena kemudahan dalam proses dan keunggulan dalam sifat-sifat fisis kulit samaknya. Namun saat ini masyarakat menghendaki suatu produk yang ramah lingkungan. Bahan penyamak nabati dapat dikatakan sebagai bahan penyamak ramah lingkungan sebab limbah produknya mudah terdegradasi. Salah satu kelemahan dalam penggunaan samak nabati adalah kemampuan penyerapan airnya yang tinggi. Pada penelitian ini digunakan bahan water repellent yang mempunyai sifat untuk menekan kemampuan penyerapan air. Maksud dari penelitian adalah untuk mengetahui pengaruh dari water repellent pada penyerapan air, sifat-sifat fisis dan morfologi kulit yang disamak dengan bahan penyamak nabati. Penelitian dilakukan dengan memvariasi jumlah water repellent dari 5; 7,5; 10; 12,5 dan 15%. Sifat-sifat fisis yang didapatkan kemudian dibandingkan dengan analisis sidik ragam dengan taraf kepercayaan 95%. Hasil penelitian menunjukkan adanya penurunan dalam sifat penyerapan airnya walaupun tidak signifikan dari 77,6% menjadi 65,39%, penurunan kuat sobek dari 41,64 menjadi 20,05 kg/cm, kuat tarik dari 227,10 menjadi 163,53 kg/cm2 dan kemuluran dari 57,11 menjadi 49,68% masing-masing untuk water repellent berturut-turut 5 dan 15%, kuat bengkuk dan WVA tidak ada perubahan yang signifikan, sedangkan untuk WVP maksimum terjadi pada penggunaan water repellent 12,5%. Hasil SEM menunjukkn adanya lapisan tipis pada serat kulit yang dapat menghambat penyerapan air. ......The term of eco-friendly leather can be interpreted as chrome-free tanned leather. Recently, almost 80% of leather is tanned using chrome tanning agent because of the ease in processing and excellence of the physical properties. Nevertheless, people nowadays want an eco-friendly leather product. Vegetable tanning materials can be said as eco-friendly tanning material because their waste degrades easily. One of the weaknesses in the use of vegetable tanning is a high water absorption capability. In this research used a water repellent material that has the properties to suppress the ability of water absorption. The purpose of the research was to determine the effect of water repellent on physical properties and morphology of leather tanned by vegetable tanning materials. Because one of the weaknesses in the vegetable tanning is its high water absorption capability, in this research, water repellent was used and varied by 5; 7.5; 10; 12.5; and 15% . Physical properties obtained were compared with analysis of variance with the significance level of 95%. The water repellent increased from 5% to 15%. The results showed a decrease in water absorption capability from 77.6% to 65.39%, tearing strength from 41.64 to 20.05 kg/cm, tensile strength from 227.10 to 163.53 kg/cm2, and elongation at break from 57.11 to 49.68%, strong swelling and WVA have no significant changes, while for WVP, the maximum use of water repellent at 12.5%. SEM results indicate the presence of a thin layer on the leather fiber that can inhibit the absorption of water.

Abstrak :
Structural adhesives have been widely used to join metal to metal, and metal to composite in automotive and aircraft structures. However, the adhesive is susceptible to water absorption from the surrounding environment and this affects the mechanical properties of the adhesive, leading to reduction in the performance of the structure. This paper investigated the water absorption and desorption behaviour of FM 73M structural adhesive film and its effect on the tensile properties. The adhesive was immersed in deionised water at a temperature of 50oC. A gravimetric method was carried out to obtain the water uptake. Dog bone specimens were used to investigate the residual tensile strength of the adhesive. Finite element modelling was performed to model the spatial moisture distribution in the adhesive and the residual tensile strength after having absorbed water. It was found that the water absorption of FM 73M deviated from Fick's second law, however the desorption behaviour followed Fick's second law. The tensile properties of the adhesive (the tensile strength and the elastic modulus) tend to decrease with the increase of water content and they are recovered after desorption at the same temperature as the absorption. The residual tensile strength was predicted using a continuum damage approach combined with environmental degradation. Good agreement has been found between the predicted and the experimental results.

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ABSTRAK
Pembangkit listrik Tenaga Uap (PLTU) berbahan bakar batubara merupakan sumber utama produksi abu batubara. Abu batubara yang dikumpulkan di bagian bawah tungku (boiler) disebut coal bottom ash dan abu tebang sisa pembakaran disebut coal fly ash. Di negara Indonesia pemanfaatan bottom ash dan fly ash pada umumnya masih sebatas material penimbun di area landfill dikarenakan terlalu rendahnya nilai dari material tersebut. Tujuan dari riset ini adalah untuk mengungkit nilai dari pemanfaatan material bottom ash dan fly ash sebagai bahan pencampur produk industri konstruksi. Desain eksperimen dilakukan terhadap produk paving block dengan menggunakan berbagai komposisi pencampuran bottom ash dan fly ash dengan mengaplikasikan design eksperimen orthogonal array, untuk kemudian dilakukan uji kelayakan teknis yaitu uji kuat tekan, uji penyerapan air, dan uji abrasi guna memenuhi persyaratan standar SNI (Standar Nasional Indonesia). Pengujian kuat tekan paving block dilakukan pada umur 7 hari, 14 hari, dan 28 hari untuk mendapatkan hasil terbaik

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ABSTRACT
The coal-fired thermal power plant is the main source of coal ash production. Coal ash collected at the bottom of the furnace (boiler) is called coal bottom ash and fly ash remaining combustion called coal fly ash. In Indonesia, the utilization of bottom ash and fly ash generally is still limited to landfill material due to the value of the material too low. The objective of this research is to leverage the value of the utilization of bottom ash and fly ash materials as a mixer of construction industry products. Design of experiment (DoE) was conducted on paving block product using various experimental factors such as composition of sand, cement, bottom ash, fly ash, and submersion time of product. This Design of experiment (DoE) applied orthogonal array methods to finding the best mixed compositions that affect the quality of the end result. After it, the proof was performed with a compressive strength test, water absorption test and abrasion test to meet the standard requirements. Testing of compressive strength of paving block was done at 7 days, 14 days and 28 days to get the best result

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ABSTRAK
Teknik refrijerasi dengan penyerapan, yang menggunakan energi kalor yang rendah dan mampu menghasilkan pengkondisian udara serta efek refrijerasi, mendapatkan perhatian besar sebagai bagian dari teknologi konversi energi. Teknologi refrijerasi dengan penyerapan mencakup teknologi absorpsi dan teknologi adsorpsi. Naskah ini mempresentasikan desain terbaru chiller adsorpsi silica gel/air yang dikembangkan di Departemen Teknik Mesin, Universitas Indonesia. Konfigurasi chiller terdiri dari dua ruang penyerapan, dengan menggunakan rectangular finned-tube heat exchanger sebagai adsorber, kondenser and evaporator. Chiller diuji pada kondisi temperatur hot water inlet/cooling water inlet sebesar 65/30 C. Heat dan mass recovery diadopsi dalam eksperimen untuk meningkatkan kapasitas pendinginan masing-masing dengan waktu 40 dan 20 detik. Waktu siklus pendinginan pada 800,700,600 dan 500 detik untuk menghasilkan waktu optimal yang berkaitan dengan performa. Nilai rata-rata COP, SCP dan kapasitas pendinginan dihitung untuk mendapatkan performa chiller secara keseluruhan masing-masing 0,6 kW; 0,7 kW/kg dan 3 kW.Kata kunci: chiller adsorpsi; heat recovery; mass recovery; performa; penyerapan; silica gel/air

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ABSTRACT
Sorption refrigeration, which is driven by the lowgrade heat and provides the air conditioning and refrigeration effect, is paid more and more attention as one of the energy conversion technologies. Sorption technology includes absorption and adsorption technology. This paper presented a new design of silica gel water adsorption chiller which is developed in Mechanical Engineering Department, University of Indonesia. The chiller design configuration is composed of two sorption chamber, with compact rectangular finned tube heat exchanger as adsorber, condenser and evaporator. The chiller is tested under typical condition for hot water inlet cooling water inlet 65 30 C, respectively. Heat and mass recovery were adopted in experiment to increase the cooling capacity time are 40 and 20 s, respectively. The cooling time were 800,700,600 and 500 s to obtain the optimum cooling time related to the performance. Average value of COP, SCP and cooling power were calculated to obtain overall performance of the chiller are 0.6 kW 0.7 kW kg and 3 kW, respectively.Keywords adsorption chiller heat recovery mass recovery performance silica gel water sorption

Abstrak :
Oil palm empty fruit bunch (OPEFB) is one of the waste products of oil palm plantations and has not been optimally used in Riau Province, Sumatera, Indonesia. OPEFB is reduced by incineration, which causes pollution problems. However, the combustion of OPEFB generates ash, which is rich in potassium. Moreover, OPEFB fiber has good strength, low cost, low density, and biodegradability, and it can be used as composite reinforcement. However, the natural fibers in composites have poor compatibility with the matrix and relatively high moisture absorption. Hydrolysis of OPEFB ash creates a base solution that can be utilized in an alkaline treatment process to increase the mechanical properties of natural composites. The aim of this study was to investigate the effect of various extracts of OPEFB ash on the tensile strength, flexural strength, and water absorption of an OPEFB fiber-polypropylene composite. The experimental design used was the Response Surface Method-Central Composite Design (RSM-CCD). The results showed that the tensile strength increased with an increase of fiber length and concentration of the OPEFB ash extract solution, but tensile strength decreased with a longer soaking time. Flexural strength increased with an increase in fiber length but decreased with an increase in the concentration of the OPEFB ash extract solution and longer soaking time. Water absorption increased with lower and higher concentrations of OPEFB ash extract solution and fiber length and with shorter and longer soaking times. The highest tensile strength (20.100 MPa) was achieved at 5%wt alkaline concentration, 36 h soaking time, and 3 cm fiber length. The highest flexural strength (30.216 MPa) was achieved at 5%wt alkaline concentration, 12 h soaking time, and 3 cm fiber length. The lowest water absorption (0.324%) was achieved at 10%wt alkaline concentration, 24 h soaking time, and 2 cm fiber length.

Abstrak :
Oil palm empty fruit bunch (OPEFB) is one of the waste products of oil palm plantations and has not been optimally used in Riau Province, Sumatera, Indonesia. OPEFB is reduced by incineration, which causes pollution problems. However, the combustion of OPEFB generates ash, which is rich in potassium. Moreover, OPEFB fiber has good strength, low cost, low density, and biodegradability, and it can be used as composite reinforcement. However, the natural fibers in composites have poor compatibility with the matrix and relatively high moisture absorption. Hydrolysis of OPEFB ash creates a base solution that can be utilized in an alkaline treatment process to increase the mechanical properties of natural composites. The aim of this study was to investigate the effect of various extracts of OPEFB ash on the tensile strength, flexural strength, and water absorption of an OPEFB fiber-polypropylene composite. The experimental design used was the Response Surface Method-Central Composite Design (RSM-CCD). The results showed that the tensile strength increased with an increase of fiber length and concentration of the OPEFB ash extract solution, but tensile strength decreased with a longer soaking time. Flexural strength increased with an increase in fiber length but decreased with an increase in the concentration of the OPEFB ash extract solution and longer soaking time. Water absorption increased with lower and higher concentrations of OPEFB ash extract solution and fiber length and with shorter and longer soaking times. The highest tensile strength (20.100 MPa) was achieved at 5%wt alkaline concentration, 36 h soaking time, and 3 cm fiber length. The highest flexural strength (30.216 MPa) was achieved at 5%wt alkaline concentration, 12 h soaking time, and 3 cm fiber length. The lowest water absorption (0.324%) was achieved at 10%wt alkaline concentration, 24 h soaking time, and 2 cm fiber length.

Abstrak :
Lime is among the binding agents used in binding masonry units, such as brick, in many historical buildings around the world. Its physical strength, mechanical strength, and durability properties, as well as its raw material composition, can play substantial roles in the structural behavior of historic buildings. The production technologies may also differ according to their specific use in the structural layout. Hence, the characteristics of lime mortars are of interest in the assessment of the structural characteristics of historic buildings. In addition, the determination of characteristics of lime mortars is also important for the production of intervention mortars to be used in the restoration of historic buildings. This research focused on the effects of egg white on lime mortar’s physical and mechanical properties. Five mixes were prepared by maintaining a constant lime–sand–water ratio of 1:2:0.035. As the binder material, the control mixture comprised only lime putty, while various percentages of egg white in the range of 2–10% were used to prepare the remaining mixtures. An experiment was then performed with different percentages of egg white to examine the lime mortar’s axial compressive and flexural strength, as well as the water absorption. The results indicated that the compressive and flexural strength of the lime mortar increased with the increasing percentage of egg white added into lime mortar until the mixture reached 6% egg white. The addition of 8% and 10% egg white made the compressive and flexural strength start to decrease. Lime mortar that contains 6% egg white had the highest compressive and flexural strength compared to the other mix design groups. The axial compressive strength and bending strength of lime mortar can also be influenced by the air pores.

Abstrak :
ABSTRAK
komposit berpenguat serat alam dapat menjadi alternatif untuk menggantikan komposit berpenguat serat sintetis yang kurang ramah terhadap lingkungan. Serat dari tumbuhan kenaf adalah salah satu serat alam yang dapat dimanfaatkan sebagai pengganti penguat serat sintesis pada komposit. Tujuan dari penelitian ini adalah untuk mengetahui kuat lentur, daya serap air, dan kadar air pada komposit polipropilena berpenguat serat kenaf dengan variasi fraksi berat serat sesuai dengan SNI 01-4449-2006. Serat kenaf diberi perlakuan alkali sebelum digunakan sebagai penguat dengan cara direndam dalam larutan NaOH 5%. Komposit polipropilena/serat kenaf kemudian difabrikasi dengan mesin hot press. Fraksi berat serat yang digunakan pada penelitian adalah 30 wt%, 40 wt%, 50 wt%, dan sampel polipropilena murni juga difabrikasi sebagai pembanding. Komposit yang difabrikasi disebut sebagai papan serat dengan kerapatan tinggi menurut SNI karena memiliki nilai densitas 1,08 g/cc. Kuat lentur, daya serap air, dan kadar air terbaik dimiliki oleh komposit polipropilena/serat kenaf 30wt% dengan nilai masing-masing (4,77 ± 1,00) MPa, (3,61 ± 1,77) % dan (1,12 ± 0,34)%; dan nilai-nilai ini memenuhi Standard Nasional Indonesia (SNI) tentang papan serat.

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ABSTRACT
Natural fiber reinforced composites can be an alternative to replace composites with synthetic fibers reinforcement that are less environmentally friendly. Kenaf fiber which is obtained from kenaf plant is one of natural fibers that can be used as a reinforcement in composites. The purpose of this research was to determine the flexural strength, water absorbent, and water content of polypropylene/kenaf fiber composites with variations of fiber weight fraction according to SNI 01-4449-2006. Kenaf fiber was treated by alkaline treatment before being used as a reinforcement by immersing kenaf fiver in NaOH 5% solution. Polypropylene/kenaf fiber composites were fabricated with compression moulding method using a hot press machine. Fiber weight fractions used in this research were 30 wt%, 40 wt%, 50 wt%, and pristine polypropylene samples were also fabricated as a comparison. Based on SNI, the fabricated composites was called Papan Serat Kerapatan Tinggi (PSKT) because the density value was 1,08 g/cc. The flexural strength, minimum water absorption and water content were found in polypropylene/kenaf fiber composite 30wt% with the value of (4,77 ± 1,00) MPa, (3,61 ± 1,77) % and (1,12 ± 0,34)% respectively and these values met the Fiber Board Indonesian National Standard (SNI).